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/*
 * Copyright (c) 1999, 2014, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
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 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package javax.imageio;

import java.awt.Point;
import java.awt.Rectangle;
import java.awt.image.BufferedImage;
import java.awt.image.Raster;
import java.awt.image.RenderedImage;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.MissingResourceException;
import java.util.ResourceBundle;
import java.util.Set;
import javax.imageio.spi.ImageReaderSpi;
import javax.imageio.event.IIOReadWarningListener;
import javax.imageio.event.IIOReadProgressListener;
import javax.imageio.event.IIOReadUpdateListener;
import javax.imageio.metadata.IIOMetadata;
import javax.imageio.metadata.IIOMetadataFormatImpl;
import javax.imageio.stream.ImageInputStream;


An abstract superclass for parsing and decoding of images.  This
class must be subclassed by classes that read in images in the
context of the Java Image I/O framework.

 ImageReader objects are normally instantiated by the service provider interface (SPI) class for the specific format. Service provider classes (e.g., instances of ImageReaderSpi) are registered with the IIORegistry, which uses them for format recognition and presentation of available format readers and writers. 
 When an input source is set (using the setInput method), it may be marked as "seek forward only". This setting means that images contained within the input source will only be read in order, possibly allowing the reader to avoid caching portions of the input containing data associated with images that have been read previously. 
See Also:
/**
 * An abstract superclass for parsing and decoding of images.  This
 * class must be subclassed by classes that read in images in the
 * context of the Java Image I/O framework.
 *
 * <p> {@code ImageReader} objects are normally instantiated by
 * the service provider interface (SPI) class for the specific format.
 * Service provider classes (e.g., instances of
 * {@code ImageReaderSpi}) are registered with the
 * {@code IIORegistry}, which uses them for format recognition
 * and presentation of available format readers and writers.
 *
 * <p> When an input source is set (using the {@code setInput}
 * method), it may be marked as "seek forward only".  This setting
 * means that images contained within the input source will only be
 * read in order, possibly allowing the reader to avoid caching
 * portions of the input containing data associated with images that
 * have been read previously.
 *
 * @see ImageWriter
 * @see javax.imageio.spi.IIORegistry
 * @see javax.imageio.spi.ImageReaderSpi
 *
 */
public abstract class ImageReader {

    
The ImageReaderSpi that instantiated this object, or null if its identity is not known or none exists. By default it is initialized to null. 
/**
     * The {@code ImageReaderSpi} that instantiated this object,
     * or {@code null} if its identity is not known or none
     * exists.  By default it is initialized to {@code null}.
     */
    protected ImageReaderSpi originatingProvider;

    
The ImageInputStream or other Object by setInput and retrieved by getInput. By default it is initialized to null. 
/**
     * The {@code ImageInputStream} or other
     * {@code Object} by {@code setInput} and retrieved
     * by {@code getInput}.  By default it is initialized to
     * {@code null}.
     */
    protected Object input = null;

    
true if the current input source has been marked as allowing only forward seeking by setInput. By default, the value is false. 
See Also:
/**
     * {@code true} if the current input source has been marked
     * as allowing only forward seeking by {@code setInput}.  By
     * default, the value is {@code false}.
     *
     * @see #minIndex
     * @see #setInput
     */
    protected boolean seekForwardOnly = false;

    
true if the current input source has been marked as allowing metadata to be ignored by setInput. By default, the value is false. 
See Also:
/**
     * {@code true} if the current input source has been marked
     * as allowing metadata to be ignored by {@code setInput}.
     * By default, the value is {@code false}.
     *
     * @see #setInput
     */
    protected boolean ignoreMetadata = false;

    
The smallest valid index for reading, initially 0. When seekForwardOnly is true, various methods may throw an IndexOutOfBoundsException on an attempt to access data associate with an image having a lower index. 
See Also:
/**
     * The smallest valid index for reading, initially 0.  When
     * {@code seekForwardOnly} is {@code true}, various methods
     * may throw an {@code IndexOutOfBoundsException} on an
     * attempt to access data associate with an image having a lower
     * index.
     *
     * @see #seekForwardOnly
     * @see #setInput
     */
    protected int minIndex = 0;

    
An array of Locales which may be used to localize warning messages, or null if localization is not supported. 
/**
     * An array of {@code Locale}s which may be used to localize
     * warning messages, or {@code null} if localization is not
     * supported.
     */
    protected Locale[] availableLocales = null;

    
The current Locale to be used for localization, or null if none has been set. 
/**
     * The current {@code Locale} to be used for localization, or
     * {@code null} if none has been set.
     */
    protected Locale locale = null;

    
A List of currently registered IIOReadWarningListeners, initialized by default to null, which is synonymous with an empty List. 
/**
     * A {@code List} of currently registered
     * {@code IIOReadWarningListener}s, initialized by default to
     * {@code null}, which is synonymous with an empty
     * {@code List}.
     */
    protected List<IIOReadWarningListener> warningListeners = null;

    
A List of the Locales associated with each currently registered IIOReadWarningListener, initialized by default to null, which is synonymous with an empty List. 
/**
     * A {@code List} of the {@code Locale}s associated with
     * each currently registered {@code IIOReadWarningListener},
     * initialized by default to {@code null}, which is
     * synonymous with an empty {@code List}.
     */
    protected List<Locale> warningLocales = null;

    
A List of currently registered IIOReadProgressListeners, initialized by default to null, which is synonymous with an empty List. 
/**
     * A {@code List} of currently registered
     * {@code IIOReadProgressListener}s, initialized by default
     * to {@code null}, which is synonymous with an empty
     * {@code List}.
     */
    protected List<IIOReadProgressListener> progressListeners = null;

    
A List of currently registered IIOReadUpdateListeners, initialized by default to null, which is synonymous with an empty List. 
/**
     * A {@code List} of currently registered
     * {@code IIOReadUpdateListener}s, initialized by default to
     * {@code null}, which is synonymous with an empty
     * {@code List}.
     */
    protected List<IIOReadUpdateListener> updateListeners = null;

    
If true, the current read operation should be aborted. 
/**
     * If {@code true}, the current read operation should be
     * aborted.
     */
    private boolean abortFlag = false;

    
Constructs an ImageReader and sets its originatingProvider field to the supplied value. 
 Subclasses that make use of extensions should provide a constructor with signature (ImageReaderSpi,Object) in order to retrieve the extension object. If the extension object is unsuitable, an IllegalArgumentException should be thrown. 
Params:
  • originatingProvider – the ImageReaderSpi that is invoking this constructor, or null.
/**
     * Constructs an {@code ImageReader} and sets its
     * {@code originatingProvider} field to the supplied value.
     *
     * <p> Subclasses that make use of extensions should provide a
     * constructor with signature {@code (ImageReaderSpi,Object)}
     * in order to retrieve the extension object.  If
     * the extension object is unsuitable, an
     * {@code IllegalArgumentException} should be thrown.
     *
     * @param originatingProvider the {@code ImageReaderSpi} that is
     * invoking this constructor, or {@code null}.
     */
    protected ImageReader(ImageReaderSpi originatingProvider) {
        this.originatingProvider = originatingProvider;
    }

    
Returns a String identifying the format of the input source. 
 The default implementation returns originatingProvider.getFormatNames()[0]. Implementations that may not have an originating service provider, or which desire a different naming policy should override this method. 
Throws:
  • IOException – if an error occurs reading the
information from the input source.
Returns:the format name, as a String.
/**
     * Returns a {@code String} identifying the format of the
     * input source.
     *
     * <p> The default implementation returns
     * {@code originatingProvider.getFormatNames()[0]}.
     * Implementations that may not have an originating service
     * provider, or which desire a different naming policy should
     * override this method.
     *
     * @exception IOException if an error occurs reading the
     * information from the input source.
     *
     * @return the format name, as a {@code String}.
     */
    public String getFormatName() throws IOException {
        return originatingProvider.getFormatNames()[0];
    }

    
Returns the ImageReaderSpi that was passed in on the constructor. Note that this value may be null. 
See Also:
Returns:an ImageReaderSpi, or null.
/**
     * Returns the {@code ImageReaderSpi} that was passed in on
     * the constructor.  Note that this value may be {@code null}.
     *
     * @return an {@code ImageReaderSpi}, or {@code null}.
     *
     * @see ImageReaderSpi
     */
    public ImageReaderSpi getOriginatingProvider() {
        return originatingProvider;
    }

    
Sets the input source to use to the given ImageInputStream or other Object. The input source must be set before any of the query or read methods are used. If input is null, any currently set input source will be removed. In any case, the value of minIndex will be initialized to 0. 
 The seekForwardOnly parameter controls whether the value returned by getMinIndex will be increased as each image (or thumbnail, or image metadata) is read. If seekForwardOnly is true, then a call to read(index) will throw an IndexOutOfBoundsException if index < this.minIndex; otherwise, the value of minIndex will be set to index. If seekForwardOnly is false, the value of minIndex will remain 0 regardless of any read operations. 
 The ignoreMetadata parameter, if set to true, allows the reader to disregard any metadata encountered during the read. Subsequent calls to the getStreamMetadata and getImageMetadata methods may return null, and an IIOImage returned from readAll may return null from their getMetadata method. Setting this parameter may allow the reader to work more efficiently. The reader may choose to disregard this setting and return metadata normally. 
 Subclasses should take care to remove any cached
information based on the previous stream, such as header
information or partially decoded image data.

 Use of a general Object other than an ImageInputStream is intended for readers that interact directly with a capture device or imaging protocol. The set of legal classes is advertised by the reader's service provider's getInputTypes method; most readers will return a single-element array containing only ImageInputStream.class to indicate that they accept only an ImageInputStream. 
 The default implementation checks the input argument against the list returned by originatingProvider.getInputTypes() and fails if the argument is not an instance of one of the classes in the list. If the originating provider is set to null, the input is accepted only if it is an ImageInputStream. 
Params:
  • input – the ImageInputStream or other Object to use for future decoding.
  • seekForwardOnly – if true, images and metadata may only be read in ascending order from this input source.
  • ignoreMetadata – if true, metadata may be ignored during reads.
Throws:
  • IllegalArgumentException – if input is not an instance of one of the classes returned by the originating service provider's getInputTypes method, or is not an ImageInputStream.
See Also:
/**
     * Sets the input source to use to the given
     * {@code ImageInputStream} or other {@code Object}.
     * The input source must be set before any of the query or read
     * methods are used.  If {@code input} is {@code null},
     * any currently set input source will be removed.  In any case,
     * the value of {@code minIndex} will be initialized to 0.
     *
     * <p> The {@code seekForwardOnly} parameter controls whether
     * the value returned by {@code getMinIndex} will be
     * increased as each image (or thumbnail, or image metadata) is
     * read.  If {@code seekForwardOnly} is true, then a call to
     * {@code read(index)} will throw an
     * {@code IndexOutOfBoundsException} if {@code index < this.minIndex};
     * otherwise, the value of
     * {@code minIndex} will be set to {@code index}.  If
     * {@code seekForwardOnly} is {@code false}, the value of
     * {@code minIndex} will remain 0 regardless of any read
     * operations.
     *
     * <p> The {@code ignoreMetadata} parameter, if set to
     * {@code true}, allows the reader to disregard any metadata
     * encountered during the read.  Subsequent calls to the
     * {@code getStreamMetadata} and
     * {@code getImageMetadata} methods may return
     * {@code null}, and an {@code IIOImage} returned from
     * {@code readAll} may return {@code null} from their
     * {@code getMetadata} method.  Setting this parameter may
     * allow the reader to work more efficiently.  The reader may
     * choose to disregard this setting and return metadata normally.
     *
     * <p> Subclasses should take care to remove any cached
     * information based on the previous stream, such as header
     * information or partially decoded image data.
     *
     * <p> Use of a general {@code Object} other than an
     * {@code ImageInputStream} is intended for readers that
     * interact directly with a capture device or imaging protocol.
     * The set of legal classes is advertised by the reader's service
     * provider's {@code getInputTypes} method; most readers
     * will return a single-element array containing only
     * {@code ImageInputStream.class} to indicate that they
     * accept only an {@code ImageInputStream}.
     *
     * <p> The default implementation checks the {@code input}
     * argument against the list returned by
     * {@code originatingProvider.getInputTypes()} and fails
     * if the argument is not an instance of one of the classes
     * in the list.  If the originating provider is set to
     * {@code null}, the input is accepted only if it is an
     * {@code ImageInputStream}.
     *
     * @param input the {@code ImageInputStream} or other
     * {@code Object} to use for future decoding.
     * @param seekForwardOnly if {@code true}, images and metadata
     * may only be read in ascending order from this input source.
     * @param ignoreMetadata if {@code true}, metadata
     * may be ignored during reads.
     *
     * @exception IllegalArgumentException if {@code input} is
     * not an instance of one of the classes returned by the
     * originating service provider's {@code getInputTypes}
     * method, or is not an {@code ImageInputStream}.
     *
     * @see ImageInputStream
     * @see #getInput
     * @see javax.imageio.spi.ImageReaderSpi#getInputTypes
     */
    public void setInput(Object input,
                         boolean seekForwardOnly,
                         boolean ignoreMetadata) {
        if (input != null) {
            boolean found = false;
            if (originatingProvider != null) {
                Class<?>[] classes = originatingProvider.getInputTypes();
                for (int i = 0; i < classes.length; i++) {
                    if (classes[i].isInstance(input)) {
                        found = true;
                        break;
                    }
                }
            } else {
                if (input instanceof ImageInputStream) {
                    found = true;
                }
            }
            if (!found) {
                throw new IllegalArgumentException("Incorrect input type!");
            }

            this.seekForwardOnly = seekForwardOnly;
            this.ignoreMetadata = ignoreMetadata;
            this.minIndex = 0;
        }

        this.input = input;
    }

    
Sets the input source to use to the given ImageInputStream or other Object. The input source must be set before any of the query or read methods are used. If input is null, any currently set input source will be removed. In any case, the value of minIndex will be initialized to 0. 
 The seekForwardOnly parameter controls whether the value returned by getMinIndex will be increased as each image (or thumbnail, or image metadata) is read. If seekForwardOnly is true, then a call to read(index) will throw an IndexOutOfBoundsException if index < this.minIndex; otherwise, the value of minIndex will be set to index. If seekForwardOnly is false, the value of minIndex will remain 0 regardless of any read operations. 
 This method is equivalent to setInput(input, seekForwardOnly, false). 
Params:
  • input – the ImageInputStream or other Object to use for future decoding.
  • seekForwardOnly – if true, images and metadata may only be read in ascending order from this input source.
Throws:
  • IllegalArgumentException – if input is not an instance of one of the classes returned by the originating service provider's getInputTypes method, or is not an ImageInputStream.
See Also:
/**
     * Sets the input source to use to the given
     * {@code ImageInputStream} or other {@code Object}.
     * The input source must be set before any of the query or read
     * methods are used.  If {@code input} is {@code null},
     * any currently set input source will be removed.  In any case,
     * the value of {@code minIndex} will be initialized to 0.
     *
     * <p> The {@code seekForwardOnly} parameter controls whether
     * the value returned by {@code getMinIndex} will be
     * increased as each image (or thumbnail, or image metadata) is
     * read.  If {@code seekForwardOnly} is true, then a call to
     * {@code read(index)} will throw an
     * {@code IndexOutOfBoundsException} if {@code index < this.minIndex};
     * otherwise, the value of
     * {@code minIndex} will be set to {@code index}.  If
     * {@code seekForwardOnly} is {@code false}, the value of
     * {@code minIndex} will remain 0 regardless of any read
     * operations.
     *
     * <p> This method is equivalent to
     * {@code setInput(input, seekForwardOnly, false)}.
     *
     * @param input the {@code ImageInputStream} or other
     * {@code Object} to use for future decoding.
     * @param seekForwardOnly if {@code true}, images and metadata
     * may only be read in ascending order from this input source.
     *
     * @exception IllegalArgumentException if {@code input} is
     * not an instance of one of the classes returned by the
     * originating service provider's {@code getInputTypes}
     * method, or is not an {@code ImageInputStream}.
     *
     * @see #getInput
     */
    public void setInput(Object input,
                         boolean seekForwardOnly) {
        setInput(input, seekForwardOnly, false);
    }

    
Sets the input source to use to the given ImageInputStream or other Object. The input source must be set before any of the query or read methods are used. If input is null, any currently set input source will be removed. In any case, the value of minIndex will be initialized to 0. 
 This method is equivalent to setInput(input, false, false). 
Params:
  • input – the ImageInputStream or other Object to use for future decoding.
Throws:
  • IllegalArgumentException – if input is not an instance of one of the classes returned by the originating service provider's getInputTypes method, or is not an ImageInputStream.
See Also:
/**
     * Sets the input source to use to the given
     * {@code ImageInputStream} or other {@code Object}.
     * The input source must be set before any of the query or read
     * methods are used.  If {@code input} is {@code null},
     * any currently set input source will be removed.  In any case,
     * the value of {@code minIndex} will be initialized to 0.
     *
     * <p> This method is equivalent to
     * {@code setInput(input, false, false)}.
     *
     * @param input the {@code ImageInputStream} or other
     * {@code Object} to use for future decoding.
     *
     * @exception IllegalArgumentException if {@code input} is
     * not an instance of one of the classes returned by the
     * originating service provider's {@code getInputTypes}
     * method, or is not an {@code ImageInputStream}.
     *
     * @see #getInput
     */
    public void setInput(Object input) {
        setInput(input, false, false);
    }

    
Returns the ImageInputStream or other Object previously set as the input source. If the input source has not been set, null is returned. 
See Also:
Returns:the Object that will be used for future decoding, or null.
/**
     * Returns the {@code ImageInputStream} or other
     * {@code Object} previously set as the input source.  If the
     * input source has not been set, {@code null} is returned.
     *
     * @return the {@code Object} that will be used for future
     * decoding, or {@code null}.
     *
     * @see ImageInputStream
     * @see #setInput
     */
    public Object getInput() {
        return input;
    }

    
Returns true if the current input source has been marked as seek forward only by passing true as the seekForwardOnly argument to the setInput method. 
See Also:
Returns:true if the input source is seek forward only.
/**
     * Returns {@code true} if the current input source has been
     * marked as seek forward only by passing {@code true} as the
     * {@code seekForwardOnly} argument to the
     * {@code setInput} method.
     *
     * @return {@code true} if the input source is seek forward
     * only.
     *
     * @see #setInput
     */
    public boolean isSeekForwardOnly() {
        return seekForwardOnly;
    }

    
Returns true if the current input source has been marked as allowing metadata to be ignored by passing true as the ignoreMetadata argument to the setInput method. 
See Also:
Returns:true if the metadata may be ignored.
/**
     * Returns {@code true} if the current input source has been
     * marked as allowing metadata to be ignored by passing
     * {@code true} as the {@code ignoreMetadata} argument
     * to the {@code setInput} method.
     *
     * @return {@code true} if the metadata may be ignored.
     *
     * @see #setInput
     */
    public boolean isIgnoringMetadata() {
        return ignoreMetadata;
    }

    
Returns the lowest valid index for reading an image, thumbnail, or image metadata. If seekForwardOnly() is false, this value will typically remain 0, indicating that random access is possible. Otherwise, it will contain the value of the most recently accessed index, and increase in a monotonic fashion. 
Returns:the minimum legal index for reading.
/**
     * Returns the lowest valid index for reading an image, thumbnail,
     * or image metadata.  If {@code seekForwardOnly()} is
     * {@code false}, this value will typically remain 0,
     * indicating that random access is possible.  Otherwise, it will
     * contain the value of the most recently accessed index, and
     * increase in a monotonic fashion.
     *
     * @return the minimum legal index for reading.
     */
    public int getMinIndex() {
        return minIndex;
    }

    // Localization

    
Returns an array of Locales that may be used to localize warning listeners and compression settings. A return value of null indicates that localization is not supported. 
 The default implementation returns a clone of the availableLocales instance variable if it is non-null, or else returns null. 
Returns:an array of Locales that may be used as arguments to setLocale, or null.
/**
     * Returns an array of {@code Locale}s that may be used to
     * localize warning listeners and compression settings.  A return
     * value of {@code null} indicates that localization is not
     * supported.
     *
     * <p> The default implementation returns a clone of the
     * {@code availableLocales} instance variable if it is
     * non-{@code null}, or else returns {@code null}.
     *
     * @return an array of {@code Locale}s that may be used as
     * arguments to {@code setLocale}, or {@code null}.
     */
    public Locale[] getAvailableLocales() {
        if (availableLocales == null) {
            return null;
        } else {
            return availableLocales.clone();
        }
    }

    
Sets the current Locale of this ImageReader to the given value. A value of null removes any previous setting, and indicates that the reader should localize as it sees fit. 
Params:
  • locale – the desired Locale, or null.
Throws:
See Also:
/**
     * Sets the current {@code Locale} of this
     * {@code ImageReader} to the given value.  A value of
     * {@code null} removes any previous setting, and indicates
     * that the reader should localize as it sees fit.
     *
     * @param locale the desired {@code Locale}, or
     * {@code null}.
     *
     * @exception IllegalArgumentException if {@code locale} is
     * non-{@code null} but is not one of the values returned by
     * {@code getAvailableLocales}.
     *
     * @see #getLocale
     */
    public void setLocale(Locale locale) {
        if (locale != null) {
            Locale[] locales = getAvailableLocales();
            boolean found = false;
            if (locales != null) {
                for (int i = 0; i < locales.length; i++) {
                    if (locale.equals(locales[i])) {
                        found = true;
                        break;
                    }
                }
            }
            if (!found) {
                throw new IllegalArgumentException("Invalid locale!");
            }
        }
        this.locale = locale;
    }

    
Returns the currently set Locale, or null if none has been set. 
See Also:
Returns:the current Locale, or null.
/**
     * Returns the currently set {@code Locale}, or
     * {@code null} if none has been set.
     *
     * @return the current {@code Locale}, or {@code null}.
     *
     * @see #setLocale
     */
    public Locale getLocale() {
        return locale;
    }

    // Image queries

    
Returns the number of images, not including thumbnails, available
from the current input source.

 Note that some image formats (such as animated GIF) do not specify how many images are present in the stream. Thus determining the number of images will require the entire stream to be scanned and may require memory for buffering. If images are to be processed in order, it may be more efficient to simply call read with increasing indices until an IndexOutOfBoundsException is thrown to indicate that no more images are available. The allowSearch parameter may be set to false to indicate that an exhaustive search is not desired; the return value will be -1 to indicate that a search is necessary. If the input has been specified with seekForwardOnly set to true, this method throws an IllegalStateException if allowSearch is set to true. 
Params:
  • allowSearch – if true, the true number of images will be returned even if a search is required. If false, the reader may return -1 without performing the search.
Throws:
  • IllegalStateException – if the input source has not been set, or if the input has been specified with seekForwardOnly set to true.
  • IOException – if an error occurs reading the
information from the input source.
See Also:
Returns:the number of images, as an int, or -1 if allowSearch is false and a search would be required.
/**
     * Returns the number of images, not including thumbnails, available
     * from the current input source.
     *
     * <p> Note that some image formats (such as animated GIF) do not
     * specify how many images are present in the stream.  Thus
     * determining the number of images will require the entire stream
     * to be scanned and may require memory for buffering.  If images
     * are to be processed in order, it may be more efficient to
     * simply call {@code read} with increasing indices until an
     * {@code IndexOutOfBoundsException} is thrown to indicate
     * that no more images are available.  The
     * {@code allowSearch} parameter may be set to
     * {@code false} to indicate that an exhaustive search is not
     * desired; the return value will be {@code -1} to indicate
     * that a search is necessary.  If the input has been specified
     * with {@code seekForwardOnly} set to {@code true},
     * this method throws an {@code IllegalStateException} if
     * {@code allowSearch} is set to {@code true}.
     *
     * @param allowSearch if {@code true}, the true number of
     * images will be returned even if a search is required.  If
     * {@code false}, the reader may return {@code -1}
     * without performing the search.
     *
     * @return the number of images, as an {@code int}, or
     * {@code -1} if {@code allowSearch} is
     * {@code false} and a search would be required.
     *
     * @exception IllegalStateException if the input source has not been set,
     * or if the input has been specified with {@code seekForwardOnly}
     * set to {@code true}.
     * @exception IOException if an error occurs reading the
     * information from the input source.
     *
     * @see #setInput
     */
    public abstract int getNumImages(boolean allowSearch) throws IOException;

    
Returns the width in pixels of the given image within the input
source.

 If the image can be rendered to a user-specified size, then
this method returns the default width.

Params:
  • imageIndex – the index of the image to be queried.
Throws:
Returns:the width of the image, as an int.
/**
     * Returns the width in pixels of the given image within the input
     * source.
     *
     * <p> If the image can be rendered to a user-specified size, then
     * this method returns the default width.
     *
     * @param imageIndex the index of the image to be queried.
     *
     * @return the width of the image, as an {@code int}.
     *
     * @exception IllegalStateException if the input source has not been set.
     * @exception IndexOutOfBoundsException if the supplied index is
     * out of bounds.
     * @exception IOException if an error occurs reading the width
     * information from the input source.
     */
    public abstract int getWidth(int imageIndex) throws IOException;

    
Returns the height in pixels of the given image within the
input source.

 If the image can be rendered to a user-specified size, then
this method returns the default height.

Params:
  • imageIndex – the index of the image to be queried.
Throws:
Returns:the height of the image, as an int.
/**
     * Returns the height in pixels of the given image within the
     * input source.
     *
     * <p> If the image can be rendered to a user-specified size, then
     * this method returns the default height.
     *
     * @param imageIndex the index of the image to be queried.
     *
     * @return the height of the image, as an {@code int}.
     *
     * @exception IllegalStateException if the input source has not been set.
     * @exception IndexOutOfBoundsException if the supplied index is
     * out of bounds.
     * @exception IOException if an error occurs reading the height
     * information from the input source.
     */
    public abstract int getHeight(int imageIndex) throws IOException;

    
Returns true if the storage format of the given image places no inherent impediment on random access to pixels. For most compressed formats, such as JPEG, this method should return false, as a large section of the image in addition to the region of interest may need to be decoded. 
 This is merely a hint for programs that wish to be efficient; all readers must be able to read arbitrary regions as specified in an ImageReadParam. 
 Note that formats that return false from this method may nonetheless allow tiling (e.g. Restart Markers in JPEG), and random access will likely be reasonably efficient on tiles. See isImageTiled. 
 A reader for which all images are guaranteed to support easy random access, or are guaranteed not to support easy random access, may return true or false respectively without accessing any image data. In such cases, it is not necessary to throw an exception even if no input source has been set or the image index is out of bounds. 
 The default implementation returns false. 
Params:
  • imageIndex – the index of the image to be queried.
Throws:
  • IllegalStateException – if an input source is required
to determine the return value, but none has been set.
  • IndexOutOfBoundsException – if an image must be
accessed to determine the return value, but the supplied index
is out of bounds.
  • IOException – if an error occurs during reading.
Returns:true if reading a region of interest of the given image is likely to be efficient.
/**
     * Returns {@code true} if the storage format of the given
     * image places no inherent impediment on random access to pixels.
     * For most compressed formats, such as JPEG, this method should
     * return {@code false}, as a large section of the image in
     * addition to the region of interest may need to be decoded.
     *
     * <p> This is merely a hint for programs that wish to be
     * efficient; all readers must be able to read arbitrary regions
     * as specified in an {@code ImageReadParam}.
     *
     * <p> Note that formats that return {@code false} from
     * this method may nonetheless allow tiling (<i>e.g.</i> Restart
     * Markers in JPEG), and random access will likely be reasonably
     * efficient on tiles.  See {@link #isImageTiled isImageTiled}.
     *
     * <p> A reader for which all images are guaranteed to support
     * easy random access, or are guaranteed not to support easy
     * random access, may return {@code true} or
     * {@code false} respectively without accessing any image
     * data.  In such cases, it is not necessary to throw an exception
     * even if no input source has been set or the image index is out
     * of bounds.
     *
     * <p> The default implementation returns {@code false}.
     *
     * @param imageIndex the index of the image to be queried.
     *
     * @return {@code true} if reading a region of interest of
     * the given image is likely to be efficient.
     *
     * @exception IllegalStateException if an input source is required
     * to determine the return value, but none has been set.
     * @exception IndexOutOfBoundsException if an image must be
     * accessed to determine the return value, but the supplied index
     * is out of bounds.
     * @exception IOException if an error occurs during reading.
     */
    public boolean isRandomAccessEasy(int imageIndex) throws IOException {
        return false;
    }

    
Returns the aspect ratio of the given image (that is, its width divided by its height) as a float. For images that are inherently resizable, this method provides a way to determine the appropriate width given a desired height, or vice versa. For non-resizable images, the true width and height are used. 
 The default implementation simply returns (float)getWidth(imageIndex)/getHeight(imageIndex). 
Params:
  • imageIndex – the index of the image to be queried.
Throws:
Returns:a float indicating the aspect ratio of the given image.
/**
     * Returns the aspect ratio of the given image (that is, its width
     * divided by its height) as a {@code float}.  For images
     * that are inherently resizable, this method provides a way to
     * determine the appropriate width given a desired height, or vice
     * versa.  For non-resizable images, the true width and height
     * are used.
     *
     * <p> The default implementation simply returns
     * {@code (float)getWidth(imageIndex)/getHeight(imageIndex)}.
     *
     * @param imageIndex the index of the image to be queried.
     *
     * @return a {@code float} indicating the aspect ratio of the
     * given image.
     *
     * @exception IllegalStateException if the input source has not been set.
     * @exception IndexOutOfBoundsException if the supplied index is
     * out of bounds.
     * @exception IOException if an error occurs during reading.
     */
    public float getAspectRatio(int imageIndex) throws IOException {
        return (float)getWidth(imageIndex)/getHeight(imageIndex);
    }

    
Returns an ImageTypeSpecifier indicating the
SampleModel and ColorModel which most closely represents the "raw" internal format of the image. If there is no close match then a type which preserves the most information from the image should be returned. The returned value should also be included in the list of values returned by getImageTypes. 
 The default implementation simply returns the first entry from the list provided by getImageType. 
Params:
  • imageIndex – the index of the image to be queried.
Throws:
Returns:an ImageTypeSpecifier.
/**
     * Returns an <code>ImageTypeSpecifier</code> indicating the
     * <code>SampleModel</code> and <code>ColorModel</code> which most
     * closely represents the "raw" internal format of the image.  If
     * there is no close match then a type which preserves the most
     * information from the image should be returned.  The returned value
     * should also be included in the list of values returned by
     * {@code getImageTypes}.
     *
     * <p> The default implementation simply returns the first entry
     * from the list provided by {@code getImageType}.
     *
     * @param imageIndex the index of the image to be queried.
     *
     * @return an {@code ImageTypeSpecifier}.
     *
     * @exception IllegalStateException if the input source has not been set.
     * @exception IndexOutOfBoundsException if the supplied index is
     * out of bounds.
     * @exception IOException if an error occurs reading the format
     * information from the input source.
     */
    public ImageTypeSpecifier getRawImageType(int imageIndex)
        throws IOException {
        return getImageTypes(imageIndex).next();
    }

    
Returns an Iterator containing possible image types to which the given image may be decoded, in the form of ImageTypeSpecifierss. At least one legal image type will be returned. 
 The first element of the iterator should be the most
"natural" type for decoding the image with as little loss as
possible.  For example, for a JPEG image the first entry should
be an RGB image, even though the image data is stored
internally in a YCbCr color space.

Params:
  • imageIndex – the index of the image to be retrieved.
Throws:
See Also:
Returns:an Iterator containing at least one ImageTypeSpecifier representing suggested image types for decoding the current given image.
/**
     * Returns an {@code Iterator} containing possible image
     * types to which the given image may be decoded, in the form of
     * {@code ImageTypeSpecifiers}s.  At least one legal image
     * type will be returned.
     *
     * <p> The first element of the iterator should be the most
     * "natural" type for decoding the image with as little loss as
     * possible.  For example, for a JPEG image the first entry should
     * be an RGB image, even though the image data is stored
     * internally in a YCbCr color space.
     *
     * @param imageIndex the index of the image to be
     * {@code retrieved}.
     *
     * @return an {@code Iterator} containing at least one
     * {@code ImageTypeSpecifier} representing suggested image
     * types for decoding the current given image.
     *
     * @exception IllegalStateException if the input source has not been set.
     * @exception IndexOutOfBoundsException if the supplied index is
     * out of bounds.
     * @exception IOException if an error occurs reading the format
     * information from the input source.
     *
     * @see ImageReadParam#setDestination(BufferedImage)
     * @see ImageReadParam#setDestinationType(ImageTypeSpecifier)
     */
    public abstract Iterator<ImageTypeSpecifier>
        getImageTypes(int imageIndex) throws IOException;

    
Returns a default ImageReadParam object appropriate for this format. All subclasses should define a set of default values for all parameters and return them with this call. This method may be called before the input source is set. 
 The default implementation constructs and returns a new ImageReadParam object that does not allow source scaling (i.e., it returns new ImageReadParam(). 
Returns:an ImageReadParam object which may be used to control the decoding process using a set of default settings.
/**
     * Returns a default {@code ImageReadParam} object
     * appropriate for this format.  All subclasses should define a
     * set of default values for all parameters and return them with
     * this call.  This method may be called before the input source
     * is set.
     *
     * <p> The default implementation constructs and returns a new
     * {@code ImageReadParam} object that does not allow source
     * scaling (<i>i.e.</i>, it returns
     * {@code new ImageReadParam()}.
     *
     * @return an {@code ImageReadParam} object which may be used
     * to control the decoding process using a set of default settings.
     */
    public ImageReadParam getDefaultReadParam() {
        return new ImageReadParam();
    }

    
Returns an IIOMetadata object representing the metadata associated with the input source as a whole (i.e., not associated with any particular image), or null if the reader does not support reading metadata, is set to ignore metadata, or if no metadata is available. 
Throws:
Returns:an IIOMetadata object, or null.
/**
     * Returns an {@code IIOMetadata} object representing the
     * metadata associated with the input source as a whole (i.e., not
     * associated with any particular image), or {@code null} if
     * the reader does not support reading metadata, is set to ignore
     * metadata, or if no metadata is available.
     *
     * @return an {@code IIOMetadata} object, or {@code null}.
     *
     * @exception IOException if an error occurs during reading.
     */
    public abstract IIOMetadata getStreamMetadata() throws IOException;

    
Returns an IIOMetadata object representing the metadata associated with the input source as a whole (i.e., not associated with any particular image). If no such data exists, null is returned. 
 The resulting metadata object is only responsible for returning documents in the format named by formatName. Within any documents that are returned, only nodes whose names are members of nodeNames are required to be returned. In this way, the amount of metadata processing done by the reader may be kept to a minimum, based on what information is actually needed. 
 If formatName is not the name of a supported metadata format, null is returned. 
 In all cases, it is legal to return a more capable metadata
object than strictly necessary.  The format name and node names
are merely hints that may be used to reduce the reader's
workload.

 The default implementation simply returns the result of calling getStreamMetadata(), after checking that the format name is supported. If it is not, null is returned. 
Params:
  • formatName – a metadata format name that may be used to retrieve a document from the returned IIOMetadata object.
  • nodeNames – a Set containing the names of nodes that may be contained in a retrieved document.
Throws:
Returns:an IIOMetadata object, or null.
/**
     * Returns an {@code IIOMetadata} object representing the
     * metadata associated with the input source as a whole (i.e.,
     * not associated with any particular image).  If no such data
     * exists, {@code null} is returned.
     *
     * <p> The resulting metadata object is only responsible for
     * returning documents in the format named by
     * {@code formatName}.  Within any documents that are
     * returned, only nodes whose names are members of
     * {@code nodeNames} are required to be returned.  In this
     * way, the amount of metadata processing done by the reader may
     * be kept to a minimum, based on what information is actually
     * needed.
     *
     * <p> If {@code formatName} is not the name of a supported
     * metadata format, {@code null} is returned.
     *
     * <p> In all cases, it is legal to return a more capable metadata
     * object than strictly necessary.  The format name and node names
     * are merely hints that may be used to reduce the reader's
     * workload.
     *
     * <p> The default implementation simply returns the result of
     * calling {@code getStreamMetadata()}, after checking that
     * the format name is supported.  If it is not,
     * {@code null} is returned.
     *
     * @param formatName a metadata format name that may be used to retrieve
     * a document from the returned {@code IIOMetadata} object.
     * @param nodeNames a {@code Set} containing the names of
     * nodes that may be contained in a retrieved document.
     *
     * @return an {@code IIOMetadata} object, or {@code null}.
     *
     * @exception IllegalArgumentException if {@code formatName}
     * is {@code null}.
     * @exception IllegalArgumentException if {@code nodeNames}
     * is {@code null}.
     * @exception IOException if an error occurs during reading.
     */
    public IIOMetadata getStreamMetadata(String formatName,
                                         Set<String> nodeNames)
        throws IOException
    {
        return getMetadata(formatName, nodeNames, true, 0);
    }

    private IIOMetadata getMetadata(String formatName,
                                    Set<String> nodeNames,
                                    boolean wantStream,
                                    int imageIndex) throws IOException {
        if (formatName == null) {
            throw new IllegalArgumentException("formatName == null!");
        }
        if (nodeNames == null) {
            throw new IllegalArgumentException("nodeNames == null!");
        }
        IIOMetadata metadata =
            wantStream
            ? getStreamMetadata()
            : getImageMetadata(imageIndex);
        if (metadata != null) {
            if (metadata.isStandardMetadataFormatSupported() &&
                formatName.equals
                (IIOMetadataFormatImpl.standardMetadataFormatName)) {
                return metadata;
            }
            String nativeName = metadata.getNativeMetadataFormatName();
            if (nativeName != null && formatName.equals(nativeName)) {
                return metadata;
            }
            String[] extraNames = metadata.getExtraMetadataFormatNames();
            if (extraNames != null) {
                for (int i = 0; i < extraNames.length; i++) {
                    if (formatName.equals(extraNames[i])) {
                        return metadata;
                    }
                }
            }
        }
        return null;
    }

    
Returns an IIOMetadata object containing metadata associated with the given image, or null if the reader does not support reading metadata, is set to ignore metadata, or if no metadata is available. 
Params:
  • imageIndex – the index of the image whose metadata is to
be retrieved.
Throws:
Returns:an IIOMetadata object, or null.
/**
     * Returns an {@code IIOMetadata} object containing metadata
     * associated with the given image, or {@code null} if the
     * reader does not support reading metadata, is set to ignore
     * metadata, or if no metadata is available.
     *
     * @param imageIndex the index of the image whose metadata is to
     * be retrieved.
     *
     * @return an {@code IIOMetadata} object, or
     * {@code null}.
     *
     * @exception IllegalStateException if the input source has not been
     * set.
     * @exception IndexOutOfBoundsException if the supplied index is
     * out of bounds.
     * @exception IOException if an error occurs during reading.
     */
    public abstract IIOMetadata getImageMetadata(int imageIndex)
        throws IOException;

    
Returns an IIOMetadata object representing the metadata associated with the given image, or null if the reader does not support reading metadata or none is available. 
 The resulting metadata object is only responsible for returning documents in the format named by formatName. Within any documents that are returned, only nodes whose names are members of nodeNames are required to be returned. In this way, the amount of metadata processing done by the reader may be kept to a minimum, based on what information is actually needed. 
 If formatName is not the name of a supported metadata format, null may be returned. 
 In all cases, it is legal to return a more capable metadata
object than strictly necessary.  The format name and node names
are merely hints that may be used to reduce the reader's
workload.

 The default implementation simply returns the result of calling getImageMetadata(imageIndex), after checking that the format name is supported. If it is not, null is returned. 
Params:
  • imageIndex – the index of the image whose metadata is to
be retrieved.
  • formatName – a metadata format name that may be used to retrieve a document from the returned IIOMetadata object.
  • nodeNames – a Set containing the names of nodes that may be contained in a retrieved document.
Throws:
Returns:an IIOMetadata object, or null.
/**
     * Returns an {@code IIOMetadata} object representing the
     * metadata associated with the given image, or {@code null}
     * if the reader does not support reading metadata or none
     * is available.
     *
     * <p> The resulting metadata object is only responsible for
     * returning documents in the format named by
     * {@code formatName}.  Within any documents that are
     * returned, only nodes whose names are members of
     * {@code nodeNames} are required to be returned.  In this
     * way, the amount of metadata processing done by the reader may
     * be kept to a minimum, based on what information is actually
     * needed.
     *
     * <p> If {@code formatName} is not the name of a supported
     * metadata format, {@code null} may be returned.
     *
     * <p> In all cases, it is legal to return a more capable metadata
     * object than strictly necessary.  The format name and node names
     * are merely hints that may be used to reduce the reader's
     * workload.
     *
     * <p> The default implementation simply returns the result of
     * calling {@code getImageMetadata(imageIndex)}, after
     * checking that the format name is supported.  If it is not,
     * {@code null} is returned.
     *
     * @param imageIndex the index of the image whose metadata is to
     * be retrieved.
     * @param formatName a metadata format name that may be used to retrieve
     * a document from the returned {@code IIOMetadata} object.
     * @param nodeNames a {@code Set} containing the names of
     * nodes that may be contained in a retrieved document.
     *
     * @return an {@code IIOMetadata} object, or {@code null}.
     *
     * @exception IllegalStateException if the input source has not been
     * set.
     * @exception IndexOutOfBoundsException if the supplied index is
     * out of bounds.
     * @exception IllegalArgumentException if {@code formatName}
     * is {@code null}.
     * @exception IllegalArgumentException if {@code nodeNames}
     * is {@code null}.
     * @exception IOException if an error occurs during reading.
     */
    public IIOMetadata getImageMetadata(int imageIndex,
                                        String formatName,
                                        Set<String> nodeNames)
        throws IOException {
        return getMetadata(formatName, nodeNames, false, imageIndex);
    }

    
Reads the image indexed by imageIndex and returns it as a complete BufferedImage, using a default ImageReadParam. This is a convenience method that calls read(imageIndex, null). 
 The image returned will be formatted according to the first ImageTypeSpecifier returned from getImageTypes. 
 Any registered IIOReadProgressListener objects will be notified by calling their imageStarted method, followed by calls to their imageProgress method as the read progresses. Finally their imageComplete method will be called. IIOReadUpdateListener objects may be updated at other times during the read as pixels are decoded. Finally, IIOReadWarningListener objects will receive notification of any non-fatal warnings that occur during decoding. 
Params:
  • imageIndex – the index of the image to be retrieved.
Throws:
Returns:the desired portion of the image as a BufferedImage.
/**
     * Reads the image indexed by {@code imageIndex} and returns
     * it as a complete {@code BufferedImage}, using a default
     * {@code ImageReadParam}.  This is a convenience method
     * that calls {@code read(imageIndex, null)}.
     *
     * <p> The image returned will be formatted according to the first
     * {@code ImageTypeSpecifier} returned from
     * {@code getImageTypes}.
     *
     * <p> Any registered {@code IIOReadProgressListener} objects
     * will be notified by calling their {@code imageStarted}
     * method, followed by calls to their {@code imageProgress}
     * method as the read progresses.  Finally their
     * {@code imageComplete} method will be called.
     * {@code IIOReadUpdateListener} objects may be updated at
     * other times during the read as pixels are decoded.  Finally,
     * {@code IIOReadWarningListener} objects will receive
     * notification of any non-fatal warnings that occur during
     * decoding.
     *
     * @param imageIndex the index of the image to be retrieved.
     *
     * @return the desired portion of the image as a
     * {@code BufferedImage}.
     *
     * @exception IllegalStateException if the input source has not been
     * set.
     * @exception IndexOutOfBoundsException if the supplied index is
     * out of bounds.
     * @exception IOException if an error occurs during reading.
     */
    public BufferedImage read(int imageIndex) throws IOException {
        return read(imageIndex, null);
    }

    
Reads the image indexed by imageIndex and returns it as a complete BufferedImage, using a supplied ImageReadParam. 
 The actual BufferedImage returned will be chosen using the algorithm defined by the getDestination method. 
 Any registered IIOReadProgressListener objects will be notified by calling their imageStarted method, followed by calls to their imageProgress method as the read progresses. Finally their imageComplete method will be called. IIOReadUpdateListener objects may be updated at other times during the read as pixels are decoded. Finally, IIOReadWarningListener objects will receive notification of any non-fatal warnings that occur during decoding. 
 The set of source bands to be read and destination bands to be written is determined by calling getSourceBands and getDestinationBands on the supplied ImageReadParam. If the lengths of the arrays returned by these methods differ, the set of source bands contains an index larger that the largest available source index, or the set of destination bands contains an index larger than the largest legal destination index, an IllegalArgumentException is thrown. 
 If the supplied ImageReadParam contains optional setting values not supported by this reader (e.g.
source render size or any format-specific settings), they will
be ignored.

Params:
  • imageIndex – the index of the image to be retrieved.
  • param – an ImageReadParam used to control the reading process, or null.
Throws:
Returns:the desired portion of the image as a BufferedImage.
/**
     * Reads the image indexed by {@code imageIndex} and returns
     * it as a complete {@code BufferedImage}, using a supplied
     * {@code ImageReadParam}.
     *
     * <p> The actual {@code BufferedImage} returned will be
     * chosen using the algorithm defined by the
     * {@code getDestination} method.
     *
     * <p> Any registered {@code IIOReadProgressListener} objects
     * will be notified by calling their {@code imageStarted}
     * method, followed by calls to their {@code imageProgress}
     * method as the read progresses.  Finally their
     * {@code imageComplete} method will be called.
     * {@code IIOReadUpdateListener} objects may be updated at
     * other times during the read as pixels are decoded.  Finally,
     * {@code IIOReadWarningListener} objects will receive
     * notification of any non-fatal warnings that occur during
     * decoding.
     *
     * <p> The set of source bands to be read and destination bands to
     * be written is determined by calling {@code getSourceBands}
     * and {@code getDestinationBands} on the supplied
     * {@code ImageReadParam}.  If the lengths of the arrays
     * returned by these methods differ, the set of source bands
     * contains an index larger that the largest available source
     * index, or the set of destination bands contains an index larger
     * than the largest legal destination index, an
     * {@code IllegalArgumentException} is thrown.
     *
     * <p> If the supplied {@code ImageReadParam} contains
     * optional setting values not supported by this reader (<i>e.g.</i>
     * source render size or any format-specific settings), they will
     * be ignored.
     *
     * @param imageIndex the index of the image to be retrieved.
     * @param param an {@code ImageReadParam} used to control
     * the reading process, or {@code null}.
     *
     * @return the desired portion of the image as a
     * {@code BufferedImage}.
     *
     * @exception IllegalStateException if the input source has not been
     * set.
     * @exception IndexOutOfBoundsException if the supplied index is
     * out of bounds.
     * @exception IllegalArgumentException if the set of source and
     * destination bands specified by
     * {@code param.getSourceBands} and
     * {@code param.getDestinationBands} differ in length or
     * include indices that are out of bounds.
     * @exception IllegalArgumentException if the resulting image would
     * have a width or height less than 1.
     * @exception IOException if an error occurs during reading.
     */
    public abstract BufferedImage read(int imageIndex, ImageReadParam param)
        throws IOException;

    
Reads the image indexed by imageIndex and returns an IIOImage containing the image, thumbnails, and associated image metadata, using a supplied ImageReadParam. 
 The actual BufferedImage referenced by the returned IIOImage will be chosen using the algorithm defined by the getDestination method. 
 Any registered IIOReadProgressListener objects will be notified by calling their imageStarted method, followed by calls to their imageProgress method as the read progresses. Finally their imageComplete method will be called. IIOReadUpdateListener objects may be updated at other times during the read as pixels are decoded. Finally, IIOReadWarningListener objects will receive notification of any non-fatal warnings that occur during decoding. 
 The set of source bands to be read and destination bands to be written is determined by calling getSourceBands and getDestinationBands on the supplied ImageReadParam. If the lengths of the arrays returned by these methods differ, the set of source bands contains an index larger that the largest available source index, or the set of destination bands contains an index larger than the largest legal destination index, an IllegalArgumentException is thrown. 
 Thumbnails will be returned in their entirety regardless of
the region settings.

 If the supplied ImageReadParam contains optional setting values not supported by this reader (e.g.
source render size or any format-specific settings), those
values will be ignored.

Params:
  • imageIndex – the index of the image to be retrieved.
  • param – an ImageReadParam used to control the reading process, or null.
Throws:
Returns:an IIOImage containing the desired portion of the image, a set of thumbnails, and associated image metadata.
/**
     * Reads the image indexed by {@code imageIndex} and returns
     * an {@code IIOImage} containing the image, thumbnails, and
     * associated image metadata, using a supplied
     * {@code ImageReadParam}.
     *
     * <p> The actual {@code BufferedImage} referenced by the
     * returned {@code IIOImage} will be chosen using the
     * algorithm defined by the {@code getDestination} method.
     *
     * <p> Any registered {@code IIOReadProgressListener} objects
     * will be notified by calling their {@code imageStarted}
     * method, followed by calls to their {@code imageProgress}
     * method as the read progresses.  Finally their
     * {@code imageComplete} method will be called.
     * {@code IIOReadUpdateListener} objects may be updated at
     * other times during the read as pixels are decoded.  Finally,
     * {@code IIOReadWarningListener} objects will receive
     * notification of any non-fatal warnings that occur during
     * decoding.
     *
     * <p> The set of source bands to be read and destination bands to
     * be written is determined by calling {@code getSourceBands}
     * and {@code getDestinationBands} on the supplied
     * {@code ImageReadParam}.  If the lengths of the arrays
     * returned by these methods differ, the set of source bands
     * contains an index larger that the largest available source
     * index, or the set of destination bands contains an index larger
     * than the largest legal destination index, an
     * {@code IllegalArgumentException} is thrown.
     *
     * <p> Thumbnails will be returned in their entirety regardless of
     * the region settings.
     *
     * <p> If the supplied {@code ImageReadParam} contains
     * optional setting values not supported by this reader (<i>e.g.</i>
     * source render size or any format-specific settings), those
     * values will be ignored.
     *
     * @param imageIndex the index of the image to be retrieved.
     * @param param an {@code ImageReadParam} used to control
     * the reading process, or {@code null}.
     *
     * @return an {@code IIOImage} containing the desired portion
     * of the image, a set of thumbnails, and associated image
     * metadata.
     *
     * @exception IllegalStateException if the input source has not been
     * set.
     * @exception IndexOutOfBoundsException if the supplied index is
     * out of bounds.
     * @exception IllegalArgumentException if the set of source and
     * destination bands specified by
     * {@code param.getSourceBands} and
     * {@code param.getDestinationBands} differ in length or
     * include indices that are out of bounds.
     * @exception IllegalArgumentException if the resulting image
     * would have a width or height less than 1.
     * @exception IOException if an error occurs during reading.
     */
    public IIOImage readAll(int imageIndex, ImageReadParam param)
        throws IOException {
        if (imageIndex < getMinIndex()) {
            throw new IndexOutOfBoundsException("imageIndex < getMinIndex()!");
        }

        BufferedImage im = read(imageIndex, param);

        ArrayList<BufferedImage> thumbnails = null;
        int numThumbnails = getNumThumbnails(imageIndex);
        if (numThumbnails > 0) {
            thumbnails = new ArrayList<>();
            for (int j = 0; j < numThumbnails; j++) {
                thumbnails.add(readThumbnail(imageIndex, j));
            }
        }

        IIOMetadata metadata = getImageMetadata(imageIndex);
        return new IIOImage(im, thumbnails, metadata);
    }

    
Returns an Iterator containing all the images, thumbnails, and metadata, starting at the index given by getMinIndex, from the input source in the form of IIOImage objects. An Iterator containing ImageReadParam objects is supplied; one element is consumed for each image read from the input source until no more images are available. If the read param Iterator runs out of elements, but there are still more images available from the input source, default read params are used for the remaining images. 
 If params is null, a default read param will be used for all images. 
 The actual BufferedImage referenced by the returned IIOImage will be chosen using the algorithm defined by the getDestination method. 
 Any registered IIOReadProgressListener objects will be notified by calling their sequenceStarted method once. Then, for each image decoded, there will be a call to imageStarted, followed by calls to imageProgress as the read progresses, and finally to imageComplete. The sequenceComplete method will be called after the last image has been decoded. IIOReadUpdateListener objects may be updated at other times during the read as pixels are decoded. Finally, IIOReadWarningListener objects will receive notification of any non-fatal warnings that occur during decoding. 
 The set of source bands to be read and destination bands to be written is determined by calling getSourceBands and getDestinationBands on the supplied ImageReadParam. If the lengths of the arrays returned by these methods differ, the set of source bands contains an index larger that the largest available source index, or the set of destination bands contains an index larger than the largest legal destination index, an IllegalArgumentException is thrown. 
 Thumbnails will be returned in their entirety regardless of the
region settings.

 If any of the supplied ImageReadParams contain optional setting values not supported by this reader (e.g.
source render size or any format-specific settings), they will
be ignored.

Params:
  • params – an Iterator containing ImageReadParam objects.
Throws:
See Also:
Returns:an Iterator representing the contents of the input source as IIOImages.
/**
     * Returns an {@code Iterator} containing all the images,
     * thumbnails, and metadata, starting at the index given by
     * {@code getMinIndex}, from the input source in the form of
     * {@code IIOImage} objects.  An {@code Iterator}
     * containing {@code ImageReadParam} objects is supplied; one
     * element is consumed for each image read from the input source
     * until no more images are available.  If the read param
     * {@code Iterator} runs out of elements, but there are still
     * more images available from the input source, default read
     * params are used for the remaining images.
     *
     * <p> If {@code params} is {@code null}, a default read
     * param will be used for all images.
     *
     * <p> The actual {@code BufferedImage} referenced by the
     * returned {@code IIOImage} will be chosen using the
     * algorithm defined by the {@code getDestination} method.
     *
     * <p> Any registered {@code IIOReadProgressListener} objects
     * will be notified by calling their {@code sequenceStarted}
     * method once.  Then, for each image decoded, there will be a
     * call to {@code imageStarted}, followed by calls to
     * {@code imageProgress} as the read progresses, and finally
     * to {@code imageComplete}.  The
     * {@code sequenceComplete} method will be called after the
     * last image has been decoded.
     * {@code IIOReadUpdateListener} objects may be updated at
     * other times during the read as pixels are decoded.  Finally,
     * {@code IIOReadWarningListener} objects will receive
     * notification of any non-fatal warnings that occur during
     * decoding.
     *
     * <p> The set of source bands to be read and destination bands to
     * be written is determined by calling {@code getSourceBands}
     * and {@code getDestinationBands} on the supplied
     * {@code ImageReadParam}.  If the lengths of the arrays
     * returned by these methods differ, the set of source bands
     * contains an index larger that the largest available source
     * index, or the set of destination bands contains an index larger
     * than the largest legal destination index, an
     * {@code IllegalArgumentException} is thrown.
     *
     * <p> Thumbnails will be returned in their entirety regardless of the
     * region settings.
     *
     * <p> If any of the supplied {@code ImageReadParam}s contain
     * optional setting values not supported by this reader (<i>e.g.</i>
     * source render size or any format-specific settings), they will
     * be ignored.
     *
     * @param params an {@code Iterator} containing
     * {@code ImageReadParam} objects.
     *
     * @return an {@code Iterator} representing the
     * contents of the input source as {@code IIOImage}s.
     *
     * @exception IllegalStateException if the input source has not been
     * set.
     * @exception IllegalArgumentException if any
     * non-{@code null} element of {@code params} is not an
     * {@code ImageReadParam}.
     * @exception IllegalArgumentException if the set of source and
     * destination bands specified by
     * {@code param.getSourceBands} and
     * {@code param.getDestinationBands} differ in length or
     * include indices that are out of bounds.
     * @exception IllegalArgumentException if a resulting image would
     * have a width or height less than 1.
     * @exception IOException if an error occurs during reading.
     *
     * @see ImageReadParam
     * @see IIOImage
     */
    public Iterator<IIOImage>
        readAll(Iterator<? extends ImageReadParam> params)
        throws IOException
    {
        List<IIOImage> output = new ArrayList<>();

        int imageIndex = getMinIndex();

        // Inform IIOReadProgressListeners we're starting a sequence
        processSequenceStarted(imageIndex);

        while (true) {
            // Inform IIOReadProgressListeners and IIOReadUpdateListeners
            // that we're starting a new image

            ImageReadParam param = null;
            if (params != null && params.hasNext()) {
                Object o = params.next();
                if (o != null) {
                    if (o instanceof ImageReadParam) {
                        param = (ImageReadParam)o;
                    } else {
                        throw new IllegalArgumentException
                            ("Non-ImageReadParam supplied as part of params!");
                    }
                }
            }

            BufferedImage bi = null;
            try {
                bi = read(imageIndex, param);
            } catch (IndexOutOfBoundsException e) {
                break;
            }

            ArrayList<BufferedImage> thumbnails = null;
            int numThumbnails = getNumThumbnails(imageIndex);
            if (numThumbnails > 0) {
                thumbnails = new ArrayList<>();
                for (int j = 0; j < numThumbnails; j++) {
                    thumbnails.add(readThumbnail(imageIndex, j));
                }
            }

            IIOMetadata metadata = getImageMetadata(imageIndex);
            IIOImage im = new IIOImage(bi, thumbnails, metadata);
            output.add(im);

            ++imageIndex;
        }

        // Inform IIOReadProgressListeners we're ending a sequence
        processSequenceComplete();

        return output.iterator();
    }

    
Returns true if this plug-in supports reading just a Raster of pixel data. If this method returns false, calls to readRaster or readTileRaster will throw an UnsupportedOperationException. 
 The default implementation returns false. 
See Also:
Returns:true if this plug-in supports reading raw Rasters.
/**
     * Returns {@code true} if this plug-in supports reading
     * just a {@link java.awt.image.Raster Raster} of pixel data.
     * If this method returns {@code false}, calls to
     * {@link #readRaster readRaster} or {@link #readTileRaster readTileRaster}
     * will throw an {@code UnsupportedOperationException}.
     *
     * <p> The default implementation returns {@code false}.
     *
     * @return {@code true} if this plug-in supports reading raw
     * {@code Raster}s.
     *
     * @see #readRaster
     * @see #readTileRaster
     */
    public boolean canReadRaster() {
        return false;
    }

    
Returns a new Raster object containing the raw pixel data from the image stream, without any color conversion applied. The application must determine how to interpret the pixel data by other means. Any destination or image-type parameters in the supplied ImageReadParam object are ignored, but all other parameters are used exactly as in the read method, except that any destination offset is used as a logical rather than a physical offset. The size of the returned Raster will always be that of the source region clipped to the actual image. Logical offsets in the stream itself are ignored. 
 This method allows formats that normally apply a color
conversion, such as JPEG, and formats that do not normally have an
associated colorspace, such as remote sensing or medical imaging data,
to provide access to raw pixel data.

 Any registered readUpdateListeners are ignored, as there is no BufferedImage, but all other listeners are called exactly as they are for the read method. 
 If canReadRaster() returns false, this method throws an UnsupportedOperationException. 
 If the supplied ImageReadParam contains optional setting values not supported by this reader (e.g.
source render size or any format-specific settings), they will
be ignored.

 The default implementation throws an UnsupportedOperationException. 
Params:
  • imageIndex – the index of the image to be read.
  • param – an ImageReadParam used to control the reading process, or null.
Throws:
See Also:
Returns:the desired portion of the image as a Raster.
/**
     * Returns a new {@code Raster} object containing the raw pixel data
     * from the image stream, without any color conversion applied.  The
     * application must determine how to interpret the pixel data by other
     * means.  Any destination or image-type parameters in the supplied
     * {@code ImageReadParam} object are ignored, but all other
     * parameters are used exactly as in the {@link #read read}
     * method, except that any destination offset is used as a logical rather
     * than a physical offset.  The size of the returned {@code Raster}
     * will always be that of the source region clipped to the actual image.
     * Logical offsets in the stream itself are ignored.
     *
     * <p> This method allows formats that normally apply a color
     * conversion, such as JPEG, and formats that do not normally have an
     * associated colorspace, such as remote sensing or medical imaging data,
     * to provide access to raw pixel data.
     *
     * <p> Any registered {@code readUpdateListener}s are ignored, as
     * there is no {@code BufferedImage}, but all other listeners are
     * called exactly as they are for the {@link #read read} method.
     *
     * <p> If {@link #canReadRaster canReadRaster()} returns
     * {@code false}, this method throws an
     * {@code UnsupportedOperationException}.
     *
     * <p> If the supplied {@code ImageReadParam} contains
     * optional setting values not supported by this reader (<i>e.g.</i>
     * source render size or any format-specific settings), they will
     * be ignored.
     *
     * <p> The default implementation throws an
     * {@code UnsupportedOperationException}.
     *
     * @param imageIndex the index of the image to be read.
     * @param param an {@code ImageReadParam} used to control
     * the reading process, or {@code null}.
     *
     * @return the desired portion of the image as a
     * {@code Raster}.
     *
     * @exception UnsupportedOperationException if this plug-in does not
     * support reading raw {@code Raster}s.
     * @exception IllegalStateException if the input source has not been
     * set.
     * @exception IndexOutOfBoundsException if the supplied index is
     * out of bounds.
     * @exception IOException if an error occurs during reading.
     *
     * @see #canReadRaster
     * @see #read
     * @see java.awt.image.Raster
     */
    public Raster readRaster(int imageIndex, ImageReadParam param)
        throws IOException {
        throw new UnsupportedOperationException("readRaster not supported!");
    }

    
Returns true if the image is organized into tiles, that is, equal-sized non-overlapping rectangles.

 A reader plug-in may choose whether or not to expose tiling that is present in the image as it is stored. It may even choose to advertise tiling when none is explicitly present. In general, tiling should only be advertised if there is some advantage (in speed or space) to accessing individual tiles. Regardless of whether the reader advertises tiling, it must be capable of reading an arbitrary rectangular region specified in an ImageReadParam. 
 A reader for which all images are guaranteed to be tiled, or are guaranteed not to be tiled, may return true or false respectively without accessing any image data. In such cases, it is not necessary to throw an exception even if no input source has been set or the image index is out of bounds. 
 The default implementation just returns false. 
Params:
  • imageIndex – the index of the image to be queried.
Throws:
  • IllegalStateException – if an input source is required
to determine the return value, but none has been set.
  • IndexOutOfBoundsException – if an image must be
accessed to determine the return value, but the supplied index
is out of bounds.
  • IOException – if an error occurs during reading.
Returns:true if the image is tiled.
/**
     * Returns {@code true} if the image is organized into
     * <i>tiles</i>, that is, equal-sized non-overlapping rectangles.
     *
     * <p> A reader plug-in may choose whether or not to expose tiling
     * that is present in the image as it is stored.  It may even
     * choose to advertise tiling when none is explicitly present.  In
     * general, tiling should only be advertised if there is some
     * advantage (in speed or space) to accessing individual tiles.
     * Regardless of whether the reader advertises tiling, it must be
     * capable of reading an arbitrary rectangular region specified in
     * an {@code ImageReadParam}.
     *
     * <p> A reader for which all images are guaranteed to be tiled,
     * or are guaranteed not to be tiled, may return {@code true}
     * or {@code false} respectively without accessing any image
     * data.  In such cases, it is not necessary to throw an exception
     * even if no input source has been set or the image index is out
     * of bounds.
     *
     * <p> The default implementation just returns {@code false}.
     *
     * @param imageIndex the index of the image to be queried.
     *
     * @return {@code true} if the image is tiled.
     *
     * @exception IllegalStateException if an input source is required
     * to determine the return value, but none has been set.
     * @exception IndexOutOfBoundsException if an image must be
     * accessed to determine the return value, but the supplied index
     * is out of bounds.
     * @exception IOException if an error occurs during reading.
     */
    public boolean isImageTiled(int imageIndex) throws IOException {
        return false;
    }

    
Returns the width of a tile in the given image.

 The default implementation simply returns getWidth(imageIndex), which is correct for non-tiled images. Readers that support tiling should override this method. 
Params:
  • imageIndex – the index of the image to be queried.
Throws:
Returns:the width of a tile.
/**
     * Returns the width of a tile in the given image.
     *
     * <p> The default implementation simply returns
     * {@code getWidth(imageIndex)}, which is correct for
     * non-tiled images.  Readers that support tiling should override
     * this method.
     *
     * @return the width of a tile.
     *
     * @param imageIndex the index of the image to be queried.
     *
     * @exception IllegalStateException if the input source has not been set.
     * @exception IndexOutOfBoundsException if the supplied index is
     * out of bounds.
     * @exception IOException if an error occurs during reading.
     */
    public int getTileWidth(int imageIndex) throws IOException {
        return getWidth(imageIndex);
    }

    
Returns the height of a tile in the given image.

 The default implementation simply returns getHeight(imageIndex), which is correct for non-tiled images. Readers that support tiling should override this method. 
Params:
  • imageIndex – the index of the image to be queried.
Throws:
Returns:the height of a tile.
/**
     * Returns the height of a tile in the given image.
     *
     * <p> The default implementation simply returns
     * {@code getHeight(imageIndex)}, which is correct for
     * non-tiled images.  Readers that support tiling should override
     * this method.
     *
     * @return the height of a tile.
     *
     * @param imageIndex the index of the image to be queried.
     *
     * @exception IllegalStateException if the input source has not been set.
     * @exception IndexOutOfBoundsException if the supplied index is
     * out of bounds.
     * @exception IOException if an error occurs during reading.
     */
    public int getTileHeight(int imageIndex) throws IOException {
        return getHeight(imageIndex);
    }

    
Returns the X coordinate of the upper-left corner of tile (0,
0) in the given image.

 A reader for which the tile grid X offset always has the
same value (usually 0), may return the value without accessing
any image data.  In such cases, it is not necessary to throw an
exception even if no input source has been set or the image
index is out of bounds.

 The default implementation simply returns 0, which is
correct for non-tiled images and tiled images in most formats.
Readers that support tiling with non-(0, 0) offsets should
override this method.

Params:
  • imageIndex – the index of the image to be queried.
Throws:
  • IllegalStateException – if an input source is required
to determine the return value, but none has been set.
  • IndexOutOfBoundsException – if an image must be
accessed to determine the return value, but the supplied index
is out of bounds.
  • IOException – if an error occurs during reading.
Returns:the X offset of the tile grid.
/**
     * Returns the X coordinate of the upper-left corner of tile (0,
     * 0) in the given image.
     *
     * <p> A reader for which the tile grid X offset always has the
     * same value (usually 0), may return the value without accessing
     * any image data.  In such cases, it is not necessary to throw an
     * exception even if no input source has been set or the image
     * index is out of bounds.
     *
     * <p> The default implementation simply returns 0, which is
     * correct for non-tiled images and tiled images in most formats.
     * Readers that support tiling with non-(0, 0) offsets should
     * override this method.
     *
     * @return the X offset of the tile grid.
     *
     * @param imageIndex the index of the image to be queried.
     *
     * @exception IllegalStateException if an input source is required
     * to determine the return value, but none has been set.
     * @exception IndexOutOfBoundsException if an image must be
     * accessed to determine the return value, but the supplied index
     * is out of bounds.
     * @exception IOException if an error occurs during reading.
     */
    public int getTileGridXOffset(int imageIndex) throws IOException {
        return 0;
    }

    
Returns the Y coordinate of the upper-left corner of tile (0,
0) in the given image.

 A reader for which the tile grid Y offset always has the
same value (usually 0), may return the value without accessing
any image data.  In such cases, it is not necessary to throw an
exception even if no input source has been set or the image
index is out of bounds.

 The default implementation simply returns 0, which is
correct for non-tiled images and tiled images in most formats.
Readers that support tiling with non-(0, 0) offsets should
override this method.

Params:
  • imageIndex – the index of the image to be queried.
Throws:
  • IllegalStateException – if an input source is required
to determine the return value, but none has been set.
  • IndexOutOfBoundsException – if an image must be
accessed to determine the return value, but the supplied index
is out of bounds.
  • IOException – if an error occurs during reading.
Returns:the Y offset of the tile grid.
/**
     * Returns the Y coordinate of the upper-left corner of tile (0,
     * 0) in the given image.
     *
     * <p> A reader for which the tile grid Y offset always has the
     * same value (usually 0), may return the value without accessing
     * any image data.  In such cases, it is not necessary to throw an
     * exception even if no input source has been set or the image
     * index is out of bounds.
     *
     * <p> The default implementation simply returns 0, which is
     * correct for non-tiled images and tiled images in most formats.
     * Readers that support tiling with non-(0, 0) offsets should
     * override this method.
     *
     * @return the Y offset of the tile grid.
     *
     * @param imageIndex the index of the image to be queried.
     *
     * @exception IllegalStateException if an input source is required
     * to determine the return value, but none has been set.
     * @exception IndexOutOfBoundsException if an image must be
     * accessed to determine the return value, but the supplied index
     * is out of bounds.
     * @exception IOException if an error occurs during reading.
     */
    public int getTileGridYOffset(int imageIndex) throws IOException {
        return 0;
    }

    
Reads the tile indicated by the tileX and tileY arguments, returning it as a BufferedImage. If the arguments are out of range, an IllegalArgumentException is thrown. If the image is not tiled, the values 0, 0 will return the entire image; any other values will cause an IllegalArgumentException to be thrown. 
 This method is merely a convenience equivalent to calling read(int, ImageReadParam) with a read param specifying a source region having offsets of tileX*getTileWidth(imageIndex), tileY*getTileHeight(imageIndex) and width and height of getTileWidth(imageIndex), getTileHeight(imageIndex); and subsampling factors of 1 and offsets of 0. To subsample a tile, call read with a read param specifying this region and different subsampling parameters. 
 The default implementation returns the entire image if tileX and tileY are 0, or throws an IllegalArgumentException otherwise. 
Params:
  • imageIndex – the index of the image to be retrieved.
  • tileX – the column index (starting with 0) of the tile
to be retrieved.
  • tileY – the row index (starting with 0) of the tile
to be retrieved.
Throws:
Returns:the tile as a BufferedImage.
/**
     * Reads the tile indicated by the {@code tileX} and
     * {@code tileY} arguments, returning it as a
     * {@code BufferedImage}.  If the arguments are out of range,
     * an {@code IllegalArgumentException} is thrown.  If the
     * image is not tiled, the values 0, 0 will return the entire
     * image; any other values will cause an
     * {@code IllegalArgumentException} to be thrown.
     *
     * <p> This method is merely a convenience equivalent to calling
     * {@code read(int, ImageReadParam)} with a read param
     * specifying a source region having offsets of
     * {@code tileX*getTileWidth(imageIndex)},
     * {@code tileY*getTileHeight(imageIndex)} and width and
     * height of {@code getTileWidth(imageIndex)},
     * {@code getTileHeight(imageIndex)}; and subsampling
     * factors of 1 and offsets of 0.  To subsample a tile, call
     * {@code read} with a read param specifying this region
     * and different subsampling parameters.
     *
     * <p> The default implementation returns the entire image if
     * {@code tileX} and {@code tileY} are 0, or throws
     * an {@code IllegalArgumentException} otherwise.
     *
     * @param imageIndex the index of the image to be retrieved.
     * @param tileX the column index (starting with 0) of the tile
     * to be retrieved.
     * @param tileY the row index (starting with 0) of the tile
     * to be retrieved.
     *
     * @return the tile as a {@code BufferedImage}.
     *
     * @exception IllegalStateException if the input source has not been
     * set.
     * @exception IndexOutOfBoundsException if {@code imageIndex}
     * is out of bounds.
     * @exception IllegalArgumentException if the tile indices are
     * out of bounds.
     * @exception IOException if an error occurs during reading.
     */
    public BufferedImage readTile(int imageIndex,
                                  int tileX, int tileY) throws IOException {
        if ((tileX != 0) || (tileY != 0)) {
            throw new IllegalArgumentException("Invalid tile indices");
        }
        return read(imageIndex);
    }

    
Returns a new Raster object containing the raw pixel data from the tile, without any color conversion applied. The application must determine how to interpret the pixel data by other means. 
 If canReadRaster() returns false, this method throws an UnsupportedOperationException. 
 The default implementation checks if reading Rasters is supported, and if so calls readRaster(imageIndex, null) if tileX and tileY are 0, or throws an IllegalArgumentException otherwise. 
Params:
  • imageIndex – the index of the image to be retrieved.
  • tileX – the column index (starting with 0) of the tile
to be retrieved.
  • tileY – the row index (starting with 0) of the tile
to be retrieved.
Throws:
See Also:
Returns:the tile as a Raster.
/**
     * Returns a new {@code Raster} object containing the raw
     * pixel data from the tile, without any color conversion applied.
     * The application must determine how to interpret the pixel data by other
     * means.
     *
     * <p> If {@link #canReadRaster canReadRaster()} returns
     * {@code false}, this method throws an
     * {@code UnsupportedOperationException}.
     *
     * <p> The default implementation checks if reading
     * {@code Raster}s is supported, and if so calls {@link
     * #readRaster readRaster(imageIndex, null)} if
     * {@code tileX} and {@code tileY} are 0, or throws an
     * {@code IllegalArgumentException} otherwise.
     *
     * @param imageIndex the index of the image to be retrieved.
     * @param tileX the column index (starting with 0) of the tile
     * to be retrieved.
     * @param tileY the row index (starting with 0) of the tile
     * to be retrieved.
     *
     * @return the tile as a {@code Raster}.
     *
     * @exception UnsupportedOperationException if this plug-in does not
     * support reading raw {@code Raster}s.
     * @exception IllegalArgumentException if the tile indices are
     * out of bounds.
     * @exception IllegalStateException if the input source has not been
     * set.
     * @exception IndexOutOfBoundsException if {@code imageIndex}
     * is out of bounds.
     * @exception IOException if an error occurs during reading.
     *
     * @see #readTile
     * @see #readRaster
     * @see java.awt.image.Raster
     */
    public Raster readTileRaster(int imageIndex,
                                 int tileX, int tileY) throws IOException {
        if (!canReadRaster()) {
            throw new UnsupportedOperationException
                ("readTileRaster not supported!");
        }
        if ((tileX != 0) || (tileY != 0)) {
            throw new IllegalArgumentException("Invalid tile indices");
        }
        return readRaster(imageIndex, null);
    }

    // RenderedImages

    
Returns a RenderedImage object that contains the contents of the image indexed by imageIndex. By default, the returned image is simply the BufferedImage returned by read(imageIndex, param). 
 The semantics of this method may differ from those of the other read methods in several ways. First, any destination image and/or image type set in the ImageReadParam may be ignored. Second, the usual listener calls are not guaranteed to be made, or to be meaningful if they are. This is because the returned image may not be fully populated with pixel data at the time it is returned, or indeed at any time. 
 If the supplied ImageReadParam contains optional setting values not supported by this reader (e.g.
source render size or any format-specific settings), they will
be ignored.

 The default implementation just calls read(imageIndex, param). 
Params:
  • imageIndex – the index of the image to be retrieved.
  • param – an ImageReadParam used to control the reading process, or null.
Throws:
Returns:a RenderedImage object providing a view of the image.
/**
     * Returns a {@code RenderedImage} object that contains the
     * contents of the image indexed by {@code imageIndex}.  By
     * default, the returned image is simply the
     * {@code BufferedImage} returned by
     * {@code read(imageIndex, param)}.
     *
     * <p> The semantics of this method may differ from those of the
     * other {@code read} methods in several ways.  First, any
     * destination image and/or image type set in the
     * {@code ImageReadParam} may be ignored.  Second, the usual
     * listener calls are not guaranteed to be made, or to be
     * meaningful if they are.  This is because the returned image may
     * not be fully populated with pixel data at the time it is
     * returned, or indeed at any time.
     *
     * <p> If the supplied {@code ImageReadParam} contains
     * optional setting values not supported by this reader (<i>e.g.</i>
     * source render size or any format-specific settings), they will
     * be ignored.
     *
     * <p> The default implementation just calls
     * {@link #read read(imageIndex, param)}.
     *
     * @param imageIndex the index of the image to be retrieved.
     * @param param an {@code ImageReadParam} used to control
     * the reading process, or {@code null}.
     *
     * @return a {@code RenderedImage} object providing a view of
     * the image.
     *
     * @exception IllegalStateException if the input source has not been
     * set.
     * @exception IndexOutOfBoundsException if the supplied index is
     * out of bounds.
     * @exception IllegalArgumentException if the set of source and
     * destination bands specified by
     * {@code param.getSourceBands} and
     * {@code param.getDestinationBands} differ in length or
     * include indices that are out of bounds.
     * @exception IllegalArgumentException if the resulting image
     * would have a width or height less than 1.
     * @exception IOException if an error occurs during reading.
     */
    public RenderedImage readAsRenderedImage(int imageIndex,
                                             ImageReadParam param)
        throws IOException {
        return read(imageIndex, param);
    }

    // Thumbnails

    
Returns true if the image format understood by this reader supports thumbnail preview images associated with it. The default implementation returns false. 
 If this method returns false, hasThumbnails and getNumThumbnails will return false and 0, respectively, and readThumbnail will throw an UnsupportedOperationException, regardless of their arguments. 
 A reader that does not support thumbnails need not
implement any of the thumbnail-related methods.

Returns:true if thumbnails are supported.
/**
     * Returns {@code true} if the image format understood by
     * this reader supports thumbnail preview images associated with
     * it.  The default implementation returns {@code false}.
     *
     * <p> If this method returns {@code false},
     * {@code hasThumbnails} and {@code getNumThumbnails}
     * will return {@code false} and {@code 0},
     * respectively, and {@code readThumbnail} will throw an
     * {@code UnsupportedOperationException}, regardless of their
     * arguments.
     *
     * <p> A reader that does not support thumbnails need not
     * implement any of the thumbnail-related methods.
     *
     * @return {@code true} if thumbnails are supported.
     */
    public boolean readerSupportsThumbnails() {
        return false;
    }

    
Returns true if the given image has thumbnail preview images associated with it. If the format does not support thumbnails (readerSupportsThumbnails returns false), false will be returned regardless of whether an input source has been set or whether imageIndex is in bounds. 
 The default implementation returns true if getNumThumbnails returns a value greater than 0. 
Params:
  • imageIndex – the index of the image being queried.
Throws:
Returns:true if the given image has thumbnails.
/**
     * Returns {@code true} if the given image has thumbnail
     * preview images associated with it.  If the format does not
     * support thumbnails ({@code readerSupportsThumbnails}
     * returns {@code false}), {@code false} will be
     * returned regardless of whether an input source has been set or
     * whether {@code imageIndex} is in bounds.
     *
     * <p> The default implementation returns {@code true} if
     * {@code getNumThumbnails} returns a value greater than 0.
     *
     * @param imageIndex the index of the image being queried.
     *
     * @return {@code true} if the given image has thumbnails.
     *
     * @exception IllegalStateException if the reader supports
     * thumbnails but the input source has not been set.
     * @exception IndexOutOfBoundsException if the reader supports
     * thumbnails but {@code imageIndex} is out of bounds.
     * @exception IOException if an error occurs during reading.
     */
    public boolean hasThumbnails(int imageIndex) throws IOException {
        return getNumThumbnails(imageIndex) > 0;
    }

    
Returns the number of thumbnail preview images associated with the given image. If the format does not support thumbnails, (readerSupportsThumbnails returns false), 0 will be returned regardless of whether an input source has been set or whether imageIndex is in bounds. 
 The default implementation returns 0 without checking its
argument.

Params:
  • imageIndex – the index of the image being queried.
Throws:
Returns:the number of thumbnails associated with the given
image.
/**
     * Returns the number of thumbnail preview images associated with
     * the given image.  If the format does not support thumbnails,
     * ({@code readerSupportsThumbnails} returns
     * {@code false}), {@code 0} will be returned regardless
     * of whether an input source has been set or whether
     * {@code imageIndex} is in bounds.
     *
     * <p> The default implementation returns 0 without checking its
     * argument.
     *
     * @param imageIndex the index of the image being queried.
     *
     * @return the number of thumbnails associated with the given
     * image.
     *
     * @exception IllegalStateException if the reader supports
     * thumbnails but the input source has not been set.
     * @exception IndexOutOfBoundsException if the reader supports
     * thumbnails but {@code imageIndex} is out of bounds.
     * @exception IOException if an error occurs during reading.
     */
    public int getNumThumbnails(int imageIndex)
        throws IOException {
        return 0;
    }

    
Returns the width of the thumbnail preview image indexed by thumbnailIndex, associated with the image indexed by ImageIndex. 
 If the reader does not support thumbnails, (readerSupportsThumbnails returns false), an UnsupportedOperationException will be thrown. 
 The default implementation simply returns readThumbnail(imageindex, thumbnailIndex).getWidth(). Subclasses should therefore override this method if possible in order to avoid forcing the thumbnail to be read. 
Params:
  • imageIndex – the index of the image to be retrieved.
  • thumbnailIndex – the index of the thumbnail to be retrieved.
Throws:
Returns:the width of the desired thumbnail as an int.
/**
     * Returns the width of the thumbnail preview image indexed by
     * {@code thumbnailIndex}, associated with the image indexed
     * by {@code ImageIndex}.
     *
     * <p> If the reader does not support thumbnails,
     * ({@code readerSupportsThumbnails} returns
     * {@code false}), an {@code UnsupportedOperationException}
     * will be thrown.
     *
     * <p> The default implementation simply returns
     * {@code readThumbnail(imageindex, thumbnailIndex).getWidth()}.
     * Subclasses should therefore
     * override this method if possible in order to avoid forcing the
     * thumbnail to be read.
     *
     * @param imageIndex the index of the image to be retrieved.
     * @param thumbnailIndex the index of the thumbnail to be retrieved.
     *
     * @return the width of the desired thumbnail as an {@code int}.
     *
     * @exception UnsupportedOperationException if thumbnails are not
     * supported.
     * @exception IllegalStateException if the input source has not been set.
     * @exception IndexOutOfBoundsException if either of the supplied
     * indices are out of bounds.
     * @exception IOException if an error occurs during reading.
     */
    public int getThumbnailWidth(int imageIndex, int thumbnailIndex)
        throws IOException {
        return readThumbnail(imageIndex, thumbnailIndex).getWidth();
    }

    
Returns the height of the thumbnail preview image indexed by thumbnailIndex, associated with the image indexed by ImageIndex. 
 If the reader does not support thumbnails, (readerSupportsThumbnails returns false), an UnsupportedOperationException will be thrown. 
 The default implementation simply returns readThumbnail(imageindex, thumbnailIndex).getHeight(). Subclasses should therefore override this method if possible in order to avoid forcing the thumbnail to be read. 
Params:
  • imageIndex – the index of the image to be retrieved.
  • thumbnailIndex – the index of the thumbnail to be retrieved.
Throws:
Returns:the height of the desired thumbnail as an int.
/**
     * Returns the height of the thumbnail preview image indexed by
     * {@code thumbnailIndex}, associated with the image indexed
     * by {@code ImageIndex}.
     *
     * <p> If the reader does not support thumbnails,
     * ({@code readerSupportsThumbnails} returns
     * {@code false}), an {@code UnsupportedOperationException}
     * will be thrown.
     *
     * <p> The default implementation simply returns
     * {@code readThumbnail(imageindex, thumbnailIndex).getHeight()}.
     * Subclasses should therefore override
     * this method if possible in order to avoid
     * forcing the thumbnail to be read.
     *
     * @param imageIndex the index of the image to be retrieved.
     * @param thumbnailIndex the index of the thumbnail to be retrieved.
     *
     * @return the height of the desired thumbnail as an {@code int}.
     *
     * @exception UnsupportedOperationException if thumbnails are not
     * supported.
     * @exception IllegalStateException if the input source has not been set.
     * @exception IndexOutOfBoundsException if either of the supplied
     * indices are out of bounds.
     * @exception IOException if an error occurs during reading.
     */
    public int getThumbnailHeight(int imageIndex, int thumbnailIndex)
        throws IOException {
        return readThumbnail(imageIndex, thumbnailIndex).getHeight();
    }

    
Returns the thumbnail preview image indexed by thumbnailIndex, associated with the image indexed by ImageIndex as a BufferedImage. 
 Any registered IIOReadProgressListener objects will be notified by calling their thumbnailStarted, thumbnailProgress, and thumbnailComplete methods. 
 If the reader does not support thumbnails, (readerSupportsThumbnails returns false), an UnsupportedOperationException will be thrown regardless of whether an input source has been set or whether the indices are in bounds. 
 The default implementation throws an UnsupportedOperationException. 
Params:
  • imageIndex – the index of the image to be retrieved.
  • thumbnailIndex – the index of the thumbnail to be retrieved.
Throws:
Returns:the desired thumbnail as a BufferedImage.
/**
     * Returns the thumbnail preview image indexed by
     * {@code thumbnailIndex}, associated with the image indexed
     * by {@code ImageIndex} as a {@code BufferedImage}.
     *
     * <p> Any registered {@code IIOReadProgressListener} objects
     * will be notified by calling their
     * {@code thumbnailStarted}, {@code thumbnailProgress},
     * and {@code thumbnailComplete} methods.
     *
     * <p> If the reader does not support thumbnails,
     * ({@code readerSupportsThumbnails} returns
     * {@code false}), an {@code UnsupportedOperationException}
     * will be thrown regardless of whether an input source has been
     * set or whether the indices are in bounds.
     *
     * <p> The default implementation throws an
     * {@code UnsupportedOperationException}.
     *
     * @param imageIndex the index of the image to be retrieved.
     * @param thumbnailIndex the index of the thumbnail to be retrieved.
     *
     * @return the desired thumbnail as a {@code BufferedImage}.
     *
     * @exception UnsupportedOperationException if thumbnails are not
     * supported.
     * @exception IllegalStateException if the input source has not been set.
     * @exception IndexOutOfBoundsException if either of the supplied
     * indices are out of bounds.
     * @exception IOException if an error occurs during reading.
     */
    public BufferedImage readThumbnail(int imageIndex,
                                       int thumbnailIndex)
        throws IOException {
        throw new UnsupportedOperationException("Thumbnails not supported!");
    }

    // Abort

    
Requests that any current read operation be aborted.  The
contents of the image following the abort will be undefined.

 Readers should call clearAbortRequest at the beginning of each read operation, and poll the value of abortRequested regularly during the read. 
/**
     * Requests that any current read operation be aborted.  The
     * contents of the image following the abort will be undefined.
     *
     * <p> Readers should call {@code clearAbortRequest} at the
     * beginning of each read operation, and poll the value of
     * {@code abortRequested} regularly during the read.
     */
    public synchronized void abort() {
        this.abortFlag = true;
    }

    
Returns true if a request to abort the current read operation has been made since the reader was instantiated or clearAbortRequest was called. 
See Also:
Returns:true if the current read operation should be aborted.
/**
     * Returns {@code true} if a request to abort the current
     * read operation has been made since the reader was instantiated or
     * {@code clearAbortRequest} was called.
     *
     * @return {@code true} if the current read operation should
     * be aborted.
     *
     * @see #abort
     * @see #clearAbortRequest
     */
    protected synchronized boolean abortRequested() {
        return this.abortFlag;
    }

    
Clears any previous abort request. After this method has been called, abortRequested will return false. 
See Also:
/**
     * Clears any previous abort request.  After this method has been
     * called, {@code abortRequested} will return
     * {@code false}.
     *
     * @see #abort
     * @see #abortRequested
     */
    protected synchronized void clearAbortRequest() {
        this.abortFlag = false;
    }

    // Listeners

    // Add an element to a list, creating a new list if the
    // existing list is null, and return the list.
    static <T> List<T> addToList(List<T> l, T elt) {
        if (l == null) {
            l = new ArrayList<>();
        }
        l.add(elt);
        return l;
    }


    // Remove an element from a list, discarding the list if the
    // resulting list is empty, and return the list or null.
    static <T> List<T> removeFromList(List<T> l, T elt) {
        if (l == null) {
            return l;
        }
        l.remove(elt);
        if (l.size() == 0) {
            l = null;
        }
        return l;
    }

    
Adds an IIOReadWarningListener to the list of registered warning listeners. If listener is null, no exception will be thrown and no action will be taken. Messages sent to the given listener will be localized, if possible, to match the current Locale. If no Locale has been set, warning messages may be localized as the reader sees fit. 
Params:
  • listener – an IIOReadWarningListener to be registered.
See Also:
/**
     * Adds an {@code IIOReadWarningListener} to the list of
     * registered warning listeners.  If {@code listener} is
     * {@code null}, no exception will be thrown and no action
     * will be taken.  Messages sent to the given listener will be
     * localized, if possible, to match the current
     * {@code Locale}.  If no {@code Locale} has been set,
     * warning messages may be localized as the reader sees fit.
     *
     * @param listener an {@code IIOReadWarningListener} to be registered.
     *
     * @see #removeIIOReadWarningListener
     */
    public void addIIOReadWarningListener(IIOReadWarningListener listener) {
        if (listener == null) {
            return;
        }
        warningListeners = addToList(warningListeners, listener);
        warningLocales = addToList(warningLocales, getLocale());
    }

    
Removes an IIOReadWarningListener from the list of registered error listeners. If the listener was not previously registered, or if listener is null, no exception will be thrown and no action will be taken. 
Params:
  • listener – an IIOReadWarningListener to be unregistered.
See Also:
/**
     * Removes an {@code IIOReadWarningListener} from the list of
     * registered error listeners.  If the listener was not previously
     * registered, or if {@code listener} is {@code null},
     * no exception will be thrown and no action will be taken.
     *
     * @param listener an IIOReadWarningListener to be unregistered.
     *
     * @see #addIIOReadWarningListener
     */
    public void removeIIOReadWarningListener(IIOReadWarningListener listener) {
        if (listener == null || warningListeners == null) {
            return;
        }
        int index = warningListeners.indexOf(listener);
        if (index != -1) {
            warningListeners.remove(index);
            warningLocales.remove(index);
            if (warningListeners.size() == 0) {
                warningListeners = null;
                warningLocales = null;
            }
        }
    }

    
Removes all currently registered IIOReadWarningListener objects. 
 The default implementation sets the warningListeners and warningLocales instance variables to null. 
/**
     * Removes all currently registered
     * {@code IIOReadWarningListener} objects.
     *
     * <p> The default implementation sets the
     * {@code warningListeners} and {@code warningLocales}
     * instance variables to {@code null}.
     */
    public void removeAllIIOReadWarningListeners() {
        warningListeners = null;
        warningLocales = null;
    }

    
Adds an IIOReadProgressListener to the list of registered progress listeners. If listener is null, no exception will be thrown and no action will be taken. 
Params:
  • listener – an IIOReadProgressListener to be registered.
See Also:
/**
     * Adds an {@code IIOReadProgressListener} to the list of
     * registered progress listeners.  If {@code listener} is
     * {@code null}, no exception will be thrown and no action
     * will be taken.
     *
     * @param listener an IIOReadProgressListener to be registered.
     *
     * @see #removeIIOReadProgressListener
     */
    public void addIIOReadProgressListener(IIOReadProgressListener listener) {
        if (listener == null) {
            return;
        }
        progressListeners = addToList(progressListeners, listener);
    }

    
Removes an IIOReadProgressListener from the list of registered progress listeners. If the listener was not previously registered, or if listener is null, no exception will be thrown and no action will be taken. 
Params:
  • listener – an IIOReadProgressListener to be unregistered.
See Also:
/**
     * Removes an {@code IIOReadProgressListener} from the list
     * of registered progress listeners.  If the listener was not
     * previously registered, or if {@code listener} is
     * {@code null}, no exception will be thrown and no action
     * will be taken.
     *
     * @param listener an IIOReadProgressListener to be unregistered.
     *
     * @see #addIIOReadProgressListener
     */
    public void
        removeIIOReadProgressListener (IIOReadProgressListener listener) {
        if (listener == null || progressListeners == null) {
            return;
        }
        progressListeners = removeFromList(progressListeners, listener);
    }

    
Removes all currently registered IIOReadProgressListener objects. 
 The default implementation sets the progressListeners instance variable to null. 
/**
     * Removes all currently registered
     * {@code IIOReadProgressListener} objects.
     *
     * <p> The default implementation sets the
     * {@code progressListeners} instance variable to
     * {@code null}.
     */
    public void removeAllIIOReadProgressListeners() {
        progressListeners = null;
    }

    
Adds an IIOReadUpdateListener to the list of registered update listeners. If listener is null, no exception will be thrown and no action will be taken. The listener will receive notification of pixel updates as images and thumbnails are decoded, including the starts and ends of progressive passes. 
 If no update listeners are present, the reader may choose
to perform fewer updates to the pixels of the destination
images and/or thumbnails, which may result in more efficient
decoding.

 For example, in progressive JPEG decoding each pass
contains updates to a set of coefficients, which would have to
be transformed into pixel values and converted to an RGB color
space for each pass if listeners are present.  If no listeners
are present, the coefficients may simply be accumulated and the
final results transformed and color converted one time only.

 The final results of decoding will be the same whether or not intermediate updates are performed. Thus if only the final image is desired it may be preferable not to register any IIOReadUpdateListeners. In general, progressive updating is most effective when fetching images over a network connection that is very slow compared to local CPU processing; over a fast connection, progressive updates may actually slow down the presentation of the image. 
Params:
  • listener – an IIOReadUpdateListener to be registered.
See Also:
/**
     * Adds an {@code IIOReadUpdateListener} to the list of
     * registered update listeners.  If {@code listener} is
     * {@code null}, no exception will be thrown and no action
     * will be taken.  The listener will receive notification of pixel
     * updates as images and thumbnails are decoded, including the
     * starts and ends of progressive passes.
     *
     * <p> If no update listeners are present, the reader may choose
     * to perform fewer updates to the pixels of the destination
     * images and/or thumbnails, which may result in more efficient
     * decoding.
     *
     * <p> For example, in progressive JPEG decoding each pass
     * contains updates to a set of coefficients, which would have to
     * be transformed into pixel values and converted to an RGB color
     * space for each pass if listeners are present.  If no listeners
     * are present, the coefficients may simply be accumulated and the
     * final results transformed and color converted one time only.
     *
     * <p> The final results of decoding will be the same whether or
     * not intermediate updates are performed.  Thus if only the final
     * image is desired it may be preferable not to register any
     * {@code IIOReadUpdateListener}s.  In general, progressive
     * updating is most effective when fetching images over a network
     * connection that is very slow compared to local CPU processing;
     * over a fast connection, progressive updates may actually slow
     * down the presentation of the image.
     *
     * @param listener an IIOReadUpdateListener to be registered.
     *
     * @see #removeIIOReadUpdateListener
     */
    public void
        addIIOReadUpdateListener(IIOReadUpdateListener listener) {
        if (listener == null) {
            return;
        }
        updateListeners = addToList(updateListeners, listener);
    }

    
Removes an IIOReadUpdateListener from the list of registered update listeners. If the listener was not previously registered, or if listener is null, no exception will be thrown and no action will be taken. 
Params:
  • listener – an IIOReadUpdateListener to be unregistered.
See Also:
/**
     * Removes an {@code IIOReadUpdateListener} from the list of
     * registered update listeners.  If the listener was not
     * previously registered, or if {@code listener} is
     * {@code null}, no exception will be thrown and no action
     * will be taken.
     *
     * @param listener an IIOReadUpdateListener to be unregistered.
     *
     * @see #addIIOReadUpdateListener
     */
    public void removeIIOReadUpdateListener(IIOReadUpdateListener listener) {
        if (listener == null || updateListeners == null) {
            return;
        }
        updateListeners = removeFromList(updateListeners, listener);
    }

    
Removes all currently registered IIOReadUpdateListener objects. 
 The default implementation sets the updateListeners instance variable to null. 
/**
     * Removes all currently registered
     * {@code IIOReadUpdateListener} objects.
     *
     * <p> The default implementation sets the
     * {@code updateListeners} instance variable to
     * {@code null}.
     */
    public void removeAllIIOReadUpdateListeners() {
        updateListeners = null;
    }

    
Broadcasts the start of an sequence of image reads to all registered IIOReadProgressListeners by calling their sequenceStarted method. Subclasses may use this method as a convenience. 
Params:
  • minIndex – the lowest index being read.
/**
     * Broadcasts the start of an sequence of image reads to all
     * registered {@code IIOReadProgressListener}s by calling
     * their {@code sequenceStarted} method.  Subclasses may use
     * this method as a convenience.
     *
     * @param minIndex the lowest index being read.
     */
    protected void processSequenceStarted(int minIndex) {
        if (progressListeners == null) {
            return;
        }
        int numListeners = progressListeners.size();
        for (int i = 0; i < numListeners; i++) {
            IIOReadProgressListener listener =
                progressListeners.get(i);
            listener.sequenceStarted(this, minIndex);
        }
    }

    
Broadcasts the completion of an sequence of image reads to all registered IIOReadProgressListeners by calling their sequenceComplete method. Subclasses may use this method as a convenience. 
/**
     * Broadcasts the completion of an sequence of image reads to all
     * registered {@code IIOReadProgressListener}s by calling
     * their {@code sequenceComplete} method.  Subclasses may use
     * this method as a convenience.
     */
    protected void processSequenceComplete() {
        if (progressListeners == null) {
            return;
        }
        int numListeners = progressListeners.size();
        for (int i = 0; i < numListeners; i++) {
            IIOReadProgressListener listener =
                progressListeners.get(i);
            listener.sequenceComplete(this);
        }
    }

    
Broadcasts the start of an image read to all registered IIOReadProgressListeners by calling their imageStarted method. Subclasses may use this method as a convenience. 
Params:
  • imageIndex – the index of the image about to be read.
/**
     * Broadcasts the start of an image read to all registered
     * {@code IIOReadProgressListener}s by calling their
     * {@code imageStarted} method.  Subclasses may use this
     * method as a convenience.
     *
     * @param imageIndex the index of the image about to be read.
     */
    protected void processImageStarted(int imageIndex) {
        if (progressListeners == null) {
            return;
        }
        int numListeners = progressListeners.size();
        for (int i = 0; i < numListeners; i++) {
            IIOReadProgressListener listener =
                progressListeners.get(i);
            listener.imageStarted(this, imageIndex);
        }
    }

    
Broadcasts the current percentage of image completion to all registered IIOReadProgressListeners by calling their imageProgress method. Subclasses may use this method as a convenience. 
Params:
  • percentageDone – the current percentage of completion, as a float.
/**
     * Broadcasts the current percentage of image completion to all
     * registered {@code IIOReadProgressListener}s by calling
     * their {@code imageProgress} method.  Subclasses may use
     * this method as a convenience.
     *
     * @param percentageDone the current percentage of completion,
     * as a {@code float}.
     */
    protected void processImageProgress(float percentageDone) {
        if (progressListeners == null) {
            return;
        }
        int numListeners = progressListeners.size();
        for (int i = 0; i < numListeners; i++) {
            IIOReadProgressListener listener =
                progressListeners.get(i);
            listener.imageProgress(this, percentageDone);
        }
    }

    
Broadcasts the completion of an image read to all registered IIOReadProgressListeners by calling their imageComplete method. Subclasses may use this method as a convenience. 
/**
     * Broadcasts the completion of an image read to all registered
     * {@code IIOReadProgressListener}s by calling their
     * {@code imageComplete} method.  Subclasses may use this
     * method as a convenience.
     */
    protected void processImageComplete() {
        if (progressListeners == null) {
            return;
        }
        int numListeners = progressListeners.size();
        for (int i = 0; i < numListeners; i++) {
            IIOReadProgressListener listener =
                progressListeners.get(i);
            listener.imageComplete(this);
        }
    }

    
Broadcasts the start of a thumbnail read to all registered IIOReadProgressListeners by calling their thumbnailStarted method. Subclasses may use this method as a convenience. 
Params:
  • imageIndex – the index of the image associated with the
thumbnail.
  • thumbnailIndex – the index of the thumbnail.
/**
     * Broadcasts the start of a thumbnail read to all registered
     * {@code IIOReadProgressListener}s by calling their
     * {@code thumbnailStarted} method.  Subclasses may use this
     * method as a convenience.
     *
     * @param imageIndex the index of the image associated with the
     * thumbnail.
     * @param thumbnailIndex the index of the thumbnail.
     */
    protected void processThumbnailStarted(int imageIndex,
                                           int thumbnailIndex) {
        if (progressListeners == null) {
            return;
        }
        int numListeners = progressListeners.size();
        for (int i = 0; i < numListeners; i++) {
            IIOReadProgressListener listener =
                progressListeners.get(i);
            listener.thumbnailStarted(this, imageIndex, thumbnailIndex);
        }
    }

    
Broadcasts the current percentage of thumbnail completion to all registered IIOReadProgressListeners by calling their thumbnailProgress method. Subclasses may use this method as a convenience. 
Params:
  • percentageDone – the current percentage of completion, as a float.
/**
     * Broadcasts the current percentage of thumbnail completion to
     * all registered {@code IIOReadProgressListener}s by calling
     * their {@code thumbnailProgress} method.  Subclasses may
     * use this method as a convenience.
     *
     * @param percentageDone the current percentage of completion,
     * as a {@code float}.
     */
    protected void processThumbnailProgress(float percentageDone) {
        if (progressListeners == null) {
            return;
        }
        int numListeners = progressListeners.size();
        for (int i = 0; i < numListeners; i++) {
            IIOReadProgressListener listener =
                progressListeners.get(i);
            listener.thumbnailProgress(this, percentageDone);
        }
    }

    
Broadcasts the completion of a thumbnail read to all registered IIOReadProgressListeners by calling their thumbnailComplete method. Subclasses may use this method as a convenience. 
/**
     * Broadcasts the completion of a thumbnail read to all registered
     * {@code IIOReadProgressListener}s by calling their
     * {@code thumbnailComplete} method.  Subclasses may use this
     * method as a convenience.
     */
    protected void processThumbnailComplete() {
        if (progressListeners == null) {
            return;
        }
        int numListeners = progressListeners.size();
        for (int i = 0; i < numListeners; i++) {
            IIOReadProgressListener listener =
                progressListeners.get(i);
            listener.thumbnailComplete(this);
        }
    }

    
Broadcasts that the read has been aborted to all registered IIOReadProgressListeners by calling their readAborted method. Subclasses may use this method as a convenience. 
/**
     * Broadcasts that the read has been aborted to all registered
     * {@code IIOReadProgressListener}s by calling their
     * {@code readAborted} method.  Subclasses may use this
     * method as a convenience.
     */
    protected void processReadAborted() {
        if (progressListeners == null) {
            return;
        }
        int numListeners = progressListeners.size();
        for (int i = 0; i < numListeners; i++) {
            IIOReadProgressListener listener =
                progressListeners.get(i);
            listener.readAborted(this);
        }
    }

    
Broadcasts the beginning of a progressive pass to all registered IIOReadUpdateListeners by calling their passStarted method. Subclasses may use this method as a convenience. 
Params:
  • theImage – the BufferedImage being updated.
  • pass – the index of the current pass, starting with 0.
  • minPass – the index of the first pass that will be decoded.
  • maxPass – the index of the last pass that will be decoded.
  • minX – the X coordinate of the upper-left pixel included
in the pass.
  • minY – the X coordinate of the upper-left pixel included
in the pass.
  • periodX – the horizontal separation between pixels.
  • periodY – the vertical separation between pixels.
  • bands – an array of ints indicating the set of affected bands of the destination.
/**
     * Broadcasts the beginning of a progressive pass to all
     * registered {@code IIOReadUpdateListener}s by calling their
     * {@code passStarted} method.  Subclasses may use this
     * method as a convenience.
     *
     * @param theImage the {@code BufferedImage} being updated.
     * @param pass the index of the current pass, starting with 0.
     * @param minPass the index of the first pass that will be decoded.
     * @param maxPass the index of the last pass that will be decoded.
     * @param minX the X coordinate of the upper-left pixel included
     * in the pass.
     * @param minY the X coordinate of the upper-left pixel included
     * in the pass.
     * @param periodX the horizontal separation between pixels.
     * @param periodY the vertical separation between pixels.
     * @param bands an array of {@code int}s indicating the
     * set of affected bands of the destination.
     */
    protected void processPassStarted(BufferedImage theImage,
                                      int pass,
                                      int minPass, int maxPass,
                                      int minX, int minY,
                                      int periodX, int periodY,
                                      int[] bands) {
        if (updateListeners == null) {
            return;
        }
        int numListeners = updateListeners.size();
        for (int i = 0; i < numListeners; i++) {
            IIOReadUpdateListener listener =
                updateListeners.get(i);
            listener.passStarted(this, theImage, pass,
                                 minPass,
                                 maxPass,
                                 minX, minY,
                                 periodX, periodY,
                                 bands);
        }
    }

    
Broadcasts the update of a set of samples to all registered IIOReadUpdateListeners by calling their imageUpdate method. Subclasses may use this method as a convenience. 
Params:
  • theImage – the BufferedImage being updated.
  • minX – the X coordinate of the upper-left pixel included
in the pass.
  • minY – the X coordinate of the upper-left pixel included
in the pass.
  • width – the total width of the area being updated, including pixels being skipped if periodX > 1.
  • height – the total height of the area being updated, including pixels being skipped if periodY > 1.
  • periodX – the horizontal separation between pixels.
  • periodY – the vertical separation between pixels.
  • bands – an array of ints indicating the set of affected bands of the destination.
/**
     * Broadcasts the update of a set of samples to all registered
     * {@code IIOReadUpdateListener}s by calling their
     * {@code imageUpdate} method.  Subclasses may use this
     * method as a convenience.
     *
     * @param theImage the {@code BufferedImage} being updated.
     * @param minX the X coordinate of the upper-left pixel included
     * in the pass.
     * @param minY the X coordinate of the upper-left pixel included
     * in the pass.
     * @param width the total width of the area being updated, including
     * pixels being skipped if {@code periodX > 1}.
     * @param height the total height of the area being updated,
     * including pixels being skipped if {@code periodY > 1}.
     * @param periodX the horizontal separation between pixels.
     * @param periodY the vertical separation between pixels.
     * @param bands an array of {@code int}s indicating the
     * set of affected bands of the destination.
     */
    protected void processImageUpdate(BufferedImage theImage,
                                      int minX, int minY,
                                      int width, int height,
                                      int periodX, int periodY,
                                      int[] bands) {
        if (updateListeners == null) {
            return;
        }
        int numListeners = updateListeners.size();
        for (int i = 0; i < numListeners; i++) {
            IIOReadUpdateListener listener =
                updateListeners.get(i);
            listener.imageUpdate(this,
                                 theImage,
                                 minX, minY,
                                 width, height,
                                 periodX, periodY,
                                 bands);
        }
    }

    
Broadcasts the end of a progressive pass to all registered IIOReadUpdateListeners by calling their passComplete method. Subclasses may use this method as a convenience. 
Params:
  • theImage – the BufferedImage being updated.
/**
     * Broadcasts the end of a progressive pass to all
     * registered {@code IIOReadUpdateListener}s by calling their
     * {@code passComplete} method.  Subclasses may use this
     * method as a convenience.
     *
     * @param theImage the {@code BufferedImage} being updated.
     */
    protected void processPassComplete(BufferedImage theImage) {
        if (updateListeners == null) {
            return;
        }
        int numListeners = updateListeners.size();
        for (int i = 0; i < numListeners; i++) {
            IIOReadUpdateListener listener =
                updateListeners.get(i);
            listener.passComplete(this, theImage);
        }
    }

    
Broadcasts the beginning of a thumbnail progressive pass to all registered IIOReadUpdateListeners by calling their thumbnailPassStarted method. Subclasses may use this method as a convenience. 
Params:
  • theThumbnail – the BufferedImage thumbnail being updated.
  • pass – the index of the current pass, starting with 0.
  • minPass – the index of the first pass that will be decoded.
  • maxPass – the index of the last pass that will be decoded.
  • minX – the X coordinate of the upper-left pixel included
in the pass.
  • minY – the X coordinate of the upper-left pixel included
in the pass.
  • periodX – the horizontal separation between pixels.
  • periodY – the vertical separation between pixels.
  • bands – an array of ints indicating the set of affected bands of the destination.
/**
     * Broadcasts the beginning of a thumbnail progressive pass to all
     * registered {@code IIOReadUpdateListener}s by calling their
     * {@code thumbnailPassStarted} method.  Subclasses may use this
     * method as a convenience.
     *
     * @param theThumbnail the {@code BufferedImage} thumbnail
     * being updated.
     * @param pass the index of the current pass, starting with 0.
     * @param minPass the index of the first pass that will be decoded.
     * @param maxPass the index of the last pass that will be decoded.
     * @param minX the X coordinate of the upper-left pixel included
     * in the pass.
     * @param minY the X coordinate of the upper-left pixel included
     * in the pass.
     * @param periodX the horizontal separation between pixels.
     * @param periodY the vertical separation between pixels.
     * @param bands an array of {@code int}s indicating the
     * set of affected bands of the destination.
     */
    protected void processThumbnailPassStarted(BufferedImage theThumbnail,
                                               int pass,
                                               int minPass, int maxPass,
                                               int minX, int minY,
                                               int periodX, int periodY,
                                               int[] bands) {
        if (updateListeners == null) {
            return;
        }
        int numListeners = updateListeners.size();
        for (int i = 0; i < numListeners; i++) {
            IIOReadUpdateListener listener =
                updateListeners.get(i);
            listener.thumbnailPassStarted(this, theThumbnail, pass,
                                          minPass,
                                          maxPass,
                                          minX, minY,
                                          periodX, periodY,
                                          bands);
        }
    }

    
Broadcasts the update of a set of samples in a thumbnail image to all registered IIOReadUpdateListeners by calling their thumbnailUpdate method. Subclasses may use this method as a convenience. 
Params:
  • theThumbnail – the BufferedImage thumbnail being updated.
  • minX – the X coordinate of the upper-left pixel included
in the pass.
  • minY – the X coordinate of the upper-left pixel included
in the pass.
  • width – the total width of the area being updated, including pixels being skipped if periodX > 1.
  • height – the total height of the area being updated, including pixels being skipped if periodY > 1.
  • periodX – the horizontal separation between pixels.
  • periodY – the vertical separation between pixels.
  • bands – an array of ints indicating the set of affected bands of the destination.
/**
     * Broadcasts the update of a set of samples in a thumbnail image
     * to all registered {@code IIOReadUpdateListener}s by
     * calling their {@code thumbnailUpdate} method.  Subclasses may
     * use this method as a convenience.
     *
     * @param theThumbnail the {@code BufferedImage} thumbnail
     * being updated.
     * @param minX the X coordinate of the upper-left pixel included
     * in the pass.
     * @param minY the X coordinate of the upper-left pixel included
     * in the pass.
     * @param width the total width of the area being updated, including
     * pixels being skipped if {@code periodX > 1}.
     * @param height the total height of the area being updated,
     * including pixels being skipped if {@code periodY > 1}.
     * @param periodX the horizontal separation between pixels.
     * @param periodY the vertical separation between pixels.
     * @param bands an array of {@code int}s indicating the
     * set of affected bands of the destination.
     */
    protected void processThumbnailUpdate(BufferedImage theThumbnail,
                                          int minX, int minY,
                                          int width, int height,
                                          int periodX, int periodY,
                                          int[] bands) {
        if (updateListeners == null) {
            return;
        }
        int numListeners = updateListeners.size();
        for (int i = 0; i < numListeners; i++) {
            IIOReadUpdateListener listener =
                updateListeners.get(i);
            listener.thumbnailUpdate(this,
                                     theThumbnail,
                                     minX, minY,
                                     width, height,
                                     periodX, periodY,
                                     bands);
        }
    }

    
Broadcasts the end of a thumbnail progressive pass to all registered IIOReadUpdateListeners by calling their thumbnailPassComplete method. Subclasses may use this method as a convenience. 
Params:
  • theThumbnail – the BufferedImage thumbnail being updated.
/**
     * Broadcasts the end of a thumbnail progressive pass to all
     * registered {@code IIOReadUpdateListener}s by calling their
     * {@code thumbnailPassComplete} method.  Subclasses may use this
     * method as a convenience.
     *
     * @param theThumbnail the {@code BufferedImage} thumbnail
     * being updated.
     */
    protected void processThumbnailPassComplete(BufferedImage theThumbnail) {
        if (updateListeners == null) {
            return;
        }
        int numListeners = updateListeners.size();
        for (int i = 0; i < numListeners; i++) {
            IIOReadUpdateListener listener =
                updateListeners.get(i);
            listener.thumbnailPassComplete(this, theThumbnail);
        }
    }

    
Broadcasts a warning message to all registered IIOReadWarningListeners by calling their warningOccurred method. Subclasses may use this method as a convenience. 
Params:
  • warning – the warning message to send.
Throws:
/**
     * Broadcasts a warning message to all registered
     * {@code IIOReadWarningListener}s by calling their
     * {@code warningOccurred} method.  Subclasses may use this
     * method as a convenience.
     *
     * @param warning the warning message to send.
     *
     * @exception IllegalArgumentException if {@code warning}
     * is {@code null}.
     */
    protected void processWarningOccurred(String warning) {
        if (warningListeners == null) {
            return;
        }
        if (warning == null) {
            throw new IllegalArgumentException("warning == null!");
        }
        int numListeners = warningListeners.size();
        for (int i = 0; i < numListeners; i++) {
            IIOReadWarningListener listener =
                warningListeners.get(i);

            listener.warningOccurred(this, warning);
        }
    }

    
Broadcasts a localized warning message to all registered IIOReadWarningListeners by calling their warningOccurred method with a string taken from a ResourceBundle. Subclasses may use this method as a convenience. 
Params:
  • baseName – the base name of a set of ResourceBundles containing localized warning messages.
  • keyword – the keyword used to index the warning message within the set of ResourceBundles.
Throws:
/**
     * Broadcasts a localized warning message to all registered
     * {@code IIOReadWarningListener}s by calling their
     * {@code warningOccurred} method with a string taken
     * from a {@code ResourceBundle}.  Subclasses may use this
     * method as a convenience.
     *
     * @param baseName the base name of a set of
     * {@code ResourceBundle}s containing localized warning
     * messages.
     * @param keyword the keyword used to index the warning message
     * within the set of {@code ResourceBundle}s.
     *
     * @exception IllegalArgumentException if {@code baseName}
     * is {@code null}.
     * @exception IllegalArgumentException if {@code keyword}
     * is {@code null}.
     * @exception IllegalArgumentException if no appropriate
     * {@code ResourceBundle} may be located.
     * @exception IllegalArgumentException if the named resource is
     * not found in the located {@code ResourceBundle}.
     * @exception IllegalArgumentException if the object retrieved
     * from the {@code ResourceBundle} is not a
     * {@code String}.
     */
    protected void processWarningOccurred(String baseName,
                                          String keyword) {
        if (warningListeners == null) {
            return;
        }
        if (baseName == null) {
            throw new IllegalArgumentException("baseName == null!");
        }
        if (keyword == null) {
            throw new IllegalArgumentException("keyword == null!");
        }
        int numListeners = warningListeners.size();
        for (int i = 0; i < numListeners; i++) {
            IIOReadWarningListener listener =
                warningListeners.get(i);
            Locale locale = warningLocales.get(i);
            if (locale == null) {
                locale = Locale.getDefault();
            }

            /*
             * Only the plugin knows the messages that are provided, so we
             * can always locate the resource bundles from the same loader
             * as that for the plugin code itself.
             */
            ResourceBundle bundle = null;
            try {
                bundle = ResourceBundle.getBundle(baseName, locale, this.getClass().getModule());
            } catch (MissingResourceException mre) {
                throw new IllegalArgumentException("Bundle not found!", mre);
            }

            String warning = null;
            try {
                warning = bundle.getString(keyword);
            } catch (ClassCastException cce) {
                throw new IllegalArgumentException("Resource is not a String!", cce);
            } catch (MissingResourceException mre) {
                throw new IllegalArgumentException("Resource is missing!", mre);
            }

            listener.warningOccurred(this, warning);
        }
    }

    // State management

    
Restores the ImageReader to its initial state. 
 The default implementation calls setInput(null, false), setLocale(null), removeAllIIOReadUpdateListeners(), removeAllIIOReadWarningListeners(), removeAllIIOReadProgressListeners(), and clearAbortRequest. 
/**
     * Restores the {@code ImageReader} to its initial state.
     *
     * <p> The default implementation calls
     * {@code setInput(null, false)},
     * {@code setLocale(null)},
     * {@code removeAllIIOReadUpdateListeners()},
     * {@code removeAllIIOReadWarningListeners()},
     * {@code removeAllIIOReadProgressListeners()}, and
     * {@code clearAbortRequest}.
     */
    public void reset() {
        setInput(null, false, false);
        setLocale(null);
        removeAllIIOReadUpdateListeners();
        removeAllIIOReadProgressListeners();
        removeAllIIOReadWarningListeners();
        clearAbortRequest();
    }

    
Allows any resources held by this object to be released. The result of calling any other method (other than finalize) subsequent to a call to this method is undefined. 
It is important for applications to call this method when they know they will no longer be using this ImageReader. Otherwise, the reader may continue to hold on to resources indefinitely. 
The default implementation of this method in the superclass does
nothing.  Subclass implementations should ensure that all resources,
especially native resources, are released.

/**
     * Allows any resources held by this object to be released.  The
     * result of calling any other method (other than
     * {@code finalize}) subsequent to a call to this method
     * is undefined.
     *
     * <p>It is important for applications to call this method when they
     * know they will no longer be using this {@code ImageReader}.
     * Otherwise, the reader may continue to hold on to resources
     * indefinitely.
     *
     * <p>The default implementation of this method in the superclass does
     * nothing.  Subclass implementations should ensure that all resources,
     * especially native resources, are released.
     */
    public void dispose() {
    }

    // Utility methods

    
A utility method that may be used by readers to compute the region of the source image that should be read, taking into account any source region and subsampling offset settings in the supplied ImageReadParam. The actual subsampling factors, destination size, and destination offset are not taken into consideration, thus further clipping must take place. The computeRegions method performs all necessary clipping. 
Params:
  • param – the ImageReadParam being used, or null.
  • srcWidth – the width of the source image.
  • srcHeight – the height of the source image.
Returns:the source region as a Rectangle.
/**
     * A utility method that may be used by readers to compute the
     * region of the source image that should be read, taking into
     * account any source region and subsampling offset settings in
     * the supplied {@code ImageReadParam}.  The actual
     * subsampling factors, destination size, and destination offset
     * are <em>not</em> taken into consideration, thus further
     * clipping must take place.  The {@link #computeRegions computeRegions}
     * method performs all necessary clipping.
     *
     * @param param the {@code ImageReadParam} being used, or
     * {@code null}.
     * @param srcWidth the width of the source image.
     * @param srcHeight the height of the source image.
     *
     * @return the source region as a {@code Rectangle}.
     */
    protected static Rectangle getSourceRegion(ImageReadParam param,
                                               int srcWidth,
                                               int srcHeight) {
        Rectangle sourceRegion = new Rectangle(0, 0, srcWidth, srcHeight);
        if (param != null) {
            Rectangle region = param.getSourceRegion();
            if (region != null) {
                sourceRegion = sourceRegion.intersection(region);
            }

            int subsampleXOffset = param.getSubsamplingXOffset();
            int subsampleYOffset = param.getSubsamplingYOffset();
            sourceRegion.x += subsampleXOffset;
            sourceRegion.y += subsampleYOffset;
            sourceRegion.width -= subsampleXOffset;
            sourceRegion.height -= subsampleYOffset;
        }

        return sourceRegion;
    }

    
Computes the source region of interest and the destination region of interest, taking the width and height of the source image, an optional destination image, and an optional ImageReadParam into account. The source region begins with the entire source image. Then that is clipped to the source region specified in the ImageReadParam, if one is specified. 
 If either of the destination offsets are negative, the
source region is clipped so that its top left will coincide
with the top left of the destination image, taking subsampling
into account.  Then the result is clipped to the destination
image on the right and bottom, if one is specified, taking
subsampling and destination offsets into account.

 Similarly, the destination region begins with the source image, is translated to the destination offset given in the ImageReadParam if there is one, and finally is clipped to the destination image, if there is one. 
 If either the source or destination regions end up having a width or height of 0, an IllegalArgumentException is thrown. 
 The getSourceRegion> method may be used if only source clipping is desired. 
Params:
  • param – an ImageReadParam, or null.
  • srcWidth – the width of the source image.
  • srcHeight – the height of the source image.
  • image – a BufferedImage that will be the destination image, or null.
  • srcRegion – a Rectangle that will be filled with the source region of interest.
  • destRegion – a Rectangle that will be filled with the destination region of interest.
Throws:
/**
     * Computes the source region of interest and the destination
     * region of interest, taking the width and height of the source
     * image, an optional destination image, and an optional
     * {@code ImageReadParam} into account.  The source region
     * begins with the entire source image.  Then that is clipped to
     * the source region specified in the {@code ImageReadParam},
     * if one is specified.
     *
     * <p> If either of the destination offsets are negative, the
     * source region is clipped so that its top left will coincide
     * with the top left of the destination image, taking subsampling
     * into account.  Then the result is clipped to the destination
     * image on the right and bottom, if one is specified, taking
     * subsampling and destination offsets into account.
     *
     * <p> Similarly, the destination region begins with the source
     * image, is translated to the destination offset given in the
     * {@code ImageReadParam} if there is one, and finally is
     * clipped to the destination image, if there is one.
     *
     * <p> If either the source or destination regions end up having a
     * width or height of 0, an {@code IllegalArgumentException}
     * is thrown.
     *
     * <p> The {@link #getSourceRegion getSourceRegion>}
     * method may be used if only source clipping is desired.
     *
     * @param param an {@code ImageReadParam}, or {@code null}.
     * @param srcWidth the width of the source image.
     * @param srcHeight the height of the source image.
     * @param image a {@code BufferedImage} that will be the
     * destination image, or {@code null}.
     * @param srcRegion a {@code Rectangle} that will be filled with
     * the source region of interest.
     * @param destRegion a {@code Rectangle} that will be filled with
     * the destination region of interest.
     * @exception IllegalArgumentException if {@code srcRegion}
     * is {@code null}.
     * @exception IllegalArgumentException if {@code dstRegion}
     * is {@code null}.
     * @exception IllegalArgumentException if the resulting source or
     * destination region is empty.
     */
    protected static void computeRegions(ImageReadParam param,
                                         int srcWidth,
                                         int srcHeight,
                                         BufferedImage image,
                                         Rectangle srcRegion,
                                         Rectangle destRegion) {
        if (srcRegion == null) {
            throw new IllegalArgumentException("srcRegion == null!");
        }
        if (destRegion == null) {
            throw new IllegalArgumentException("destRegion == null!");
        }

        // Start with the entire source image
        srcRegion.setBounds(0, 0, srcWidth, srcHeight);

        // Destination also starts with source image, as that is the
        // maximum extent if there is no subsampling
        destRegion.setBounds(0, 0, srcWidth, srcHeight);

        // Clip that to the param region, if there is one
        int periodX = 1;
        int periodY = 1;
        int gridX = 0;
        int gridY = 0;
        if (param != null) {
            Rectangle paramSrcRegion = param.getSourceRegion();
            if (paramSrcRegion != null) {
                srcRegion.setBounds(srcRegion.intersection(paramSrcRegion));
            }
            periodX = param.getSourceXSubsampling();
            periodY = param.getSourceYSubsampling();
            gridX = param.getSubsamplingXOffset();
            gridY = param.getSubsamplingYOffset();
            srcRegion.translate(gridX, gridY);
            srcRegion.width -= gridX;
            srcRegion.height -= gridY;
            destRegion.setLocation(param.getDestinationOffset());
        }

        // Now clip any negative destination offsets, i.e. clip
        // to the top and left of the destination image
        if (destRegion.x < 0) {
            int delta = -destRegion.x*periodX;
            srcRegion.x += delta;
            srcRegion.width -= delta;
            destRegion.x = 0;
        }
        if (destRegion.y < 0) {
            int delta = -destRegion.y*periodY;
            srcRegion.y += delta;
            srcRegion.height -= delta;
            destRegion.y = 0;
        }

        // Now clip the destination Region to the subsampled width and height
        int subsampledWidth = (srcRegion.width + periodX - 1)/periodX;
        int subsampledHeight = (srcRegion.height + periodY - 1)/periodY;
        destRegion.width = subsampledWidth;
        destRegion.height = subsampledHeight;

        // Now clip that to right and bottom of the destination image,
        // if there is one, taking subsampling into account
        if (image != null) {
            Rectangle destImageRect = new Rectangle(0, 0,
                                                    image.getWidth(),
                                                    image.getHeight());
            destRegion.setBounds(destRegion.intersection(destImageRect));
            if (destRegion.isEmpty()) {
                throw new IllegalArgumentException
                    ("Empty destination region!");
            }

            int deltaX = destRegion.x + subsampledWidth - image.getWidth();
            if (deltaX > 0) {
                srcRegion.width -= deltaX*periodX;
            }
            int deltaY =  destRegion.y + subsampledHeight - image.getHeight();
            if (deltaY > 0) {
                srcRegion.height -= deltaY*periodY;
            }
        }
        if (srcRegion.isEmpty() || destRegion.isEmpty()) {
            throw new IllegalArgumentException("Empty region!");
        }
    }

    
A utility method that may be used by readers to test the validity of the source and destination band settings of an ImageReadParam. This method may be called as soon as the reader knows both the number of bands of the source image as it exists in the input stream, and the number of bands of the destination image that being written. 
 The method retrieves the source and destination band setting arrays from param using the getSourceBands and getDestinationBands methods (or considers them to be null if param is null). If the source band setting array is null, it is considered to be equal to the array { 0, 1, ..., numSrcBands - 1 }, and similarly for the destination band setting array. 
 The method then tests that both arrays are equal in length,
and that neither array contains a value larger than the largest
available band index.

 Any failure results in an IllegalArgumentException being thrown; success results in the method returning silently. 
Params:
  • param – the ImageReadParam being used to read the image.
  • numSrcBands – the number of bands of the image as it exists
int the input source.
  • numDstBands – the number of bands in the destination image
being written.
Throws:
/**
     * A utility method that may be used by readers to test the
     * validity of the source and destination band settings of an
     * {@code ImageReadParam}.  This method may be called as soon
     * as the reader knows both the number of bands of the source
     * image as it exists in the input stream, and the number of bands
     * of the destination image that being written.
     *
     * <p> The method retrieves the source and destination band
     * setting arrays from param using the {@code getSourceBands}
     * and {@code getDestinationBands} methods (or considers them
     * to be {@code null} if {@code param} is
     * {@code null}).  If the source band setting array is
     * {@code null}, it is considered to be equal to the array
     * {@code { 0, 1, ..., numSrcBands - 1 }}, and similarly for
     * the destination band setting array.
     *
     * <p> The method then tests that both arrays are equal in length,
     * and that neither array contains a value larger than the largest
     * available band index.
     *
     * <p> Any failure results in an
     * {@code IllegalArgumentException} being thrown; success
     * results in the method returning silently.
     *
     * @param param the {@code ImageReadParam} being used to read
     * the image.
     * @param numSrcBands the number of bands of the image as it exists
     * int the input source.
     * @param numDstBands the number of bands in the destination image
     * being written.
     *
     * @exception IllegalArgumentException if {@code param}
     * contains an invalid specification of a source and/or
     * destination band subset.
     */
    protected static void checkReadParamBandSettings(ImageReadParam param,
                                                     int numSrcBands,
                                                     int numDstBands) {
        // A null param is equivalent to srcBands == dstBands == null.
        int[] srcBands = null;
        int[] dstBands = null;
        if (param != null) {
            srcBands = param.getSourceBands();
            dstBands = param.getDestinationBands();
        }

        int paramSrcBandLength =
            (srcBands == null) ? numSrcBands : srcBands.length;
        int paramDstBandLength =
            (dstBands == null) ? numDstBands : dstBands.length;

        if (paramSrcBandLength != paramDstBandLength) {
            throw new IllegalArgumentException("ImageReadParam num source & dest bands differ!");
        }

        if (srcBands != null) {
            for (int i = 0; i < srcBands.length; i++) {
                if (srcBands[i] >= numSrcBands) {
                    throw new IllegalArgumentException("ImageReadParam source bands contains a value >= the number of source bands!");
                }
            }
        }

        if (dstBands != null) {
            for (int i = 0; i < dstBands.length; i++) {
                if (dstBands[i] >= numDstBands) {
                    throw new IllegalArgumentException("ImageReadParam dest bands contains a value >= the number of dest bands!");
                }
            }
        }
    }

    
Returns the BufferedImage to which decoded pixel data should be written. The image is determined by inspecting the supplied ImageReadParam if it is non-null; if its getDestination method returns a non-null value, that image is simply returned. Otherwise, param.getDestinationType method is called to determine if a particular image type has been specified. If so, the returned ImageTypeSpecifier is used after checking that it is equal to one of those included in imageTypes. 
 If param is null or the above steps have not yielded an image or an ImageTypeSpecifier, the first value obtained from the imageTypes parameter is used. Typically, the caller will set imageTypes to the value of getImageTypes(imageIndex). 
 Next, the dimensions of the image are determined by a call to computeRegions. The actual width and height of the image being decoded are passed in as the width and height parameters. 
Params:
  • param – an ImageReadParam to be used to get the destination image or image type, or null.
  • imageTypes – an Iterator of ImageTypeSpecifiers indicating the legal image types, with the default first.
  • width – the true width of the image or tile being decoded.
  • height – the true width of the image or tile being decoded.
Throws:
  • IIOException – if the ImageTypeSpecifier specified by param does not match any of the legal ones from imageTypes.
  • IllegalArgumentException – if imageTypes is null or empty, or if an object not of type ImageTypeSpecifier is retrieved from it.
  • IllegalArgumentException – if the resulting image would
have a width or height less than 1.
  • IllegalArgumentException – if the product of width and height is greater than Integer.MAX_VALUE.
Returns:the BufferedImage to which decoded pixel data should be written.
/**
     * Returns the {@code BufferedImage} to which decoded pixel
     * data should be written.  The image is determined by inspecting
     * the supplied {@code ImageReadParam} if it is
     * non-{@code null}; if its {@code getDestination}
     * method returns a non-{@code null} value, that image is
     * simply returned.  Otherwise,
     * {@code param.getDestinationType} method is called to
     * determine if a particular image type has been specified.  If
     * so, the returned {@code ImageTypeSpecifier} is used after
     * checking that it is equal to one of those included in
     * {@code imageTypes}.
     *
     * <p> If {@code param} is {@code null} or the above
     * steps have not yielded an image or an
     * {@code ImageTypeSpecifier}, the first value obtained from
     * the {@code imageTypes} parameter is used.  Typically, the
     * caller will set {@code imageTypes} to the value of
     * {@code getImageTypes(imageIndex)}.
     *
     * <p> Next, the dimensions of the image are determined by a call
     * to {@code computeRegions}.  The actual width and height of
     * the image being decoded are passed in as the {@code width}
     * and {@code height} parameters.
     *
     * @param param an {@code ImageReadParam} to be used to get
     * the destination image or image type, or {@code null}.
     * @param imageTypes an {@code Iterator} of
     * {@code ImageTypeSpecifier}s indicating the legal image
     * types, with the default first.
     * @param width the true width of the image or tile being decoded.
     * @param height the true width of the image or tile being decoded.
     *
     * @return the {@code BufferedImage} to which decoded pixel
     * data should be written.
     *
     * @exception IIOException if the {@code ImageTypeSpecifier}
     * specified by {@code param} does not match any of the legal
     * ones from {@code imageTypes}.
     * @exception IllegalArgumentException if {@code imageTypes}
     * is {@code null} or empty, or if an object not of type
     * {@code ImageTypeSpecifier} is retrieved from it.
     * @exception IllegalArgumentException if the resulting image would
     * have a width or height less than 1.
     * @exception IllegalArgumentException if the product of
     * {@code width} and {@code height} is greater than
     * {@code Integer.MAX_VALUE}.
     */
    protected static BufferedImage
        getDestination(ImageReadParam param,
                       Iterator<ImageTypeSpecifier> imageTypes,
                       int width, int height)
        throws IIOException {
        if (imageTypes == null || !imageTypes.hasNext()) {
            throw new IllegalArgumentException("imageTypes null or empty!");
        }
        if ((long)width*height > Integer.MAX_VALUE) {
            throw new IllegalArgumentException
                ("width*height > Integer.MAX_VALUE!");
        }

        BufferedImage dest = null;
        ImageTypeSpecifier imageType = null;

        // If param is non-null, use it
        if (param != null) {
            // Try to get the image itself
            dest = param.getDestination();
            if (dest != null) {
                return dest;
            }

            // No image, get the image type
            imageType = param.getDestinationType();
        }

        // No info from param, use fallback image type
        if (imageType == null) {
            Object o = imageTypes.next();
            if (!(o instanceof ImageTypeSpecifier)) {
                throw new IllegalArgumentException
                    ("Non-ImageTypeSpecifier retrieved from imageTypes!");
            }
            imageType = (ImageTypeSpecifier)o;
        } else {
            boolean foundIt = false;
            while (imageTypes.hasNext()) {
                ImageTypeSpecifier type =
                    imageTypes.next();
                if (type.equals(imageType)) {
                    foundIt = true;
                    break;
                }
            }

            if (!foundIt) {
                throw new IIOException
                    ("Destination type from ImageReadParam does not match!");
            }
        }

        Rectangle srcRegion = new Rectangle(0,0,0,0);
        Rectangle destRegion = new Rectangle(0,0,0,0);
        computeRegions(param,
                       width,
                       height,
                       null,
                       srcRegion,
                       destRegion);

        int destWidth = destRegion.x + destRegion.width;
        int destHeight = destRegion.y + destRegion.height;
        // Create a new image based on the type specifier
        return imageType.createBufferedImage(destWidth, destHeight);
    }
}