/*
 * Copyright (C) 2017 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.graphics;

import static android.system.OsConstants.SEEK_CUR;
import static android.system.OsConstants.SEEK_SET;

import static java.lang.annotation.RetentionPolicy.SOURCE;

import android.annotation.AnyThread;
import android.annotation.IntDef;
import android.annotation.IntRange;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.annotation.Px;
import android.annotation.TestApi;
import android.annotation.WorkerThread;
import android.content.ContentResolver;
import android.content.res.AssetFileDescriptor;
import android.content.res.AssetManager;
import android.content.res.AssetManager.AssetInputStream;
import android.content.res.Resources;
import android.graphics.drawable.AnimatedImageDrawable;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.NinePatchDrawable;
import android.net.Uri;
import android.os.Build;
import android.system.ErrnoException;
import android.system.Os;
import android.util.DisplayMetrics;
import android.util.Size;
import android.util.TypedValue;

import dalvik.system.CloseGuard;

import libcore.io.IoUtils;

import java.io.File;
import java.io.FileDescriptor;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.lang.annotation.Retention;
import java.nio.ByteBuffer;
import java.util.concurrent.atomic.AtomicBoolean;

 
A class for converting encoded images (like PNG, JPEG, WEBP, GIF, or HEIF) into Drawable or Bitmap objects. 
To use it, first create a Source using one of the createSource overloads. For example, to decode from a File, call createSource(File) and pass the result to decodeDrawable(Source) or decodeBitmap(Source): 
 File file = new File(...);
 ImageDecoder.Source source = ImageDecoder.createSource(file);
 Drawable drawable = ImageDecoder.decodeDrawable(source);
 
 
To change the default settings, pass the Source and an OnHeaderDecodedListener to decodeDrawable(Source, OnHeaderDecodedListener) or decodeBitmap(Source, OnHeaderDecodedListener). For example, to create a sampled image with half the width and height of the original image, call setTargetSampleSize(2) inside onHeaderDecoded: 
 OnHeaderDecodedListener listener = new OnHeaderDecodedListener() {
     public void onHeaderDecoded(ImageDecoder decoder, ImageInfo info, Source source) {
         decoder.setTargetSampleSize(2);
     }
 };
 Drawable drawable = ImageDecoder.decodeDrawable(source, listener);
 
 
The ImageInfo contains information about the encoded image, like its width and height, and the Source can be used to match to a particular Source if a single OnHeaderDecodedListener is used with multiple Source objects. 
The OnHeaderDecodedListener can also be implemented as a lambda: 
 Drawable drawable = ImageDecoder.decodeDrawable(source, (decoder, info, src) -> {
     decoder.setTargetSampleSize(2);
 });
 
 
If the encoded image is an animated GIF or WEBP, decodeDrawable will return an AnimatedImageDrawable. To start its animation, call AnimatedImageDrawable.start(): 
 Drawable drawable = ImageDecoder.decodeDrawable(source);
 if (drawable instanceof AnimatedImageDrawable) {
     ((AnimatedImageDrawable) drawable).start();
 }
 
 
By default, a Bitmap created by ImageDecoder (including one that is inside a Drawable) will be immutable (i.e. Bitmap.isMutable() returns false), and it will typically have Config Config.HARDWARE. Although these properties can be changed with setMutableRequired(true) (which is only compatible with decodeBitmap(Source) and decodeBitmap(Source, OnHeaderDecodedListener)) and setAllocator, it is also possible to apply custom effects regardless of the mutability of the final returned object by passing a PostProcessor to setPostProcessor. A PostProcessor can also be a lambda: 
 Drawable drawable = ImageDecoder.decodeDrawable(source, (decoder, info, src) -> {
     decoder.setPostProcessor((canvas) -> {
             // This will create rounded corners.
             Path path = new Path();
             path.setFillType(Path.FillType.INVERSE_EVEN_ODD);
             int width = canvas.getWidth();
             int height = canvas.getHeight();
             path.addRoundRect(0, 0, width, height, 20, 20, Path.Direction.CW);
             Paint paint = new Paint();
             paint.setAntiAlias(true);
             paint.setColor(Color.TRANSPARENT);
             paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC));
             canvas.drawPath(path, paint);
             return PixelFormat.TRANSLUCENT;
     });
 });
 
 
If the encoded image is incomplete or contains an error, or if an Exception occurs during decoding, a DecodeException will be thrown. In some cases, the ImageDecoder may have decoded part of the image. In order to display the partial image, an OnPartialImageListener must be passed to setOnPartialImageListener. For example: 
 Drawable drawable = ImageDecoder.decodeDrawable(source, (decoder, info, src) -> {
     decoder.setOnPartialImageListener((DecodeException e) -> {
             // Returning true indicates to create a Drawable or Bitmap even
             // if the whole image could not be decoded. Any remaining lines
             // will be blank.
             return true;
     });
 });
 
/**
 *  <p>A class for converting encoded images (like {@code PNG}, {@code JPEG},
 *  {@code WEBP}, {@code GIF}, or {@code HEIF}) into {@link Drawable} or
 *  {@link Bitmap} objects.
 *
 *  <p>To use it, first create a {@link Source Source} using one of the
 *  {@code createSource} overloads. For example, to decode from a {@link File}, call
 *  {@link #createSource(File)} and pass the result to {@link #decodeDrawable(Source)}
 *  or {@link #decodeBitmap(Source)}:
 *
 *  <pre class="prettyprint">
 *  File file = new File(...);
 *  ImageDecoder.Source source = ImageDecoder.createSource(file);
 *  Drawable drawable = ImageDecoder.decodeDrawable(source);
 *  </pre>
 *
 *  <p>To change the default settings, pass the {@link Source Source} and an
 *  {@link OnHeaderDecodedListener OnHeaderDecodedListener} to
 *  {@link #decodeDrawable(Source, OnHeaderDecodedListener)} or
 *  {@link #decodeBitmap(Source, OnHeaderDecodedListener)}. For example, to
 *  create a sampled image with half the width and height of the original image,
 *  call {@link #setTargetSampleSize setTargetSampleSize(2)} inside
 *  {@link OnHeaderDecodedListener#onHeaderDecoded onHeaderDecoded}:
 *
 *  <pre class="prettyprint">
 *  OnHeaderDecodedListener listener = new OnHeaderDecodedListener() {
 *      public void onHeaderDecoded(ImageDecoder decoder, ImageInfo info, Source source) {
 *          decoder.setTargetSampleSize(2);
 *      }
 *  };
 *  Drawable drawable = ImageDecoder.decodeDrawable(source, listener);
 *  </pre>
 *
 *  <p>The {@link ImageInfo ImageInfo} contains information about the encoded image, like
 *  its width and height, and the {@link Source Source} can be used to match to a particular
 *  {@link Source Source} if a single {@link OnHeaderDecodedListener OnHeaderDecodedListener}
 *  is used with multiple {@link Source Source} objects.
 *
 *  <p>The {@link OnHeaderDecodedListener OnHeaderDecodedListener} can also be implemented
 *  as a lambda:
 *
 *  <pre class="prettyprint">
 *  Drawable drawable = ImageDecoder.decodeDrawable(source, (decoder, info, src) -&gt; {
 *      decoder.setTargetSampleSize(2);
 *  });
 *  </pre>
 *
 *  <p>If the encoded image is an animated {@code GIF} or {@code WEBP},
 *  {@link #decodeDrawable decodeDrawable} will return an {@link AnimatedImageDrawable}. To
 *  start its animation, call {@link AnimatedImageDrawable#start AnimatedImageDrawable.start()}:
 *
 *  <pre class="prettyprint">
 *  Drawable drawable = ImageDecoder.decodeDrawable(source);
 *  if (drawable instanceof AnimatedImageDrawable) {
 *      ((AnimatedImageDrawable) drawable).start();
 *  }
 *  </pre>
 *
 *  <p>By default, a {@link Bitmap} created by {@link ImageDecoder} (including
 *  one that is inside a {@link Drawable}) will be immutable (i.e.
 *  {@link Bitmap#isMutable Bitmap.isMutable()} returns {@code false}), and it
 *  will typically have {@code Config} {@link Bitmap.Config#HARDWARE}. Although
 *  these properties can be changed with {@link #setMutableRequired setMutableRequired(true)}
 *  (which is only compatible with {@link #decodeBitmap(Source)} and
 *  {@link #decodeBitmap(Source, OnHeaderDecodedListener)}) and {@link #setAllocator},
 *  it is also possible to apply custom effects regardless of the mutability of
 *  the final returned object by passing a {@link PostProcessor} to
 *  {@link #setPostProcessor setPostProcessor}. A {@link PostProcessor} can also be a lambda:
 *
 *  <pre class="prettyprint">
 *  Drawable drawable = ImageDecoder.decodeDrawable(source, (decoder, info, src) -&gt; {
 *      decoder.setPostProcessor((canvas) -&gt; {
 *              // This will create rounded corners.
 *              Path path = new Path();
 *              path.setFillType(Path.FillType.INVERSE_EVEN_ODD);
 *              int width = canvas.getWidth();
 *              int height = canvas.getHeight();
 *              path.addRoundRect(0, 0, width, height, 20, 20, Path.Direction.CW);
 *              Paint paint = new Paint();
 *              paint.setAntiAlias(true);
 *              paint.setColor(Color.TRANSPARENT);
 *              paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC));
 *              canvas.drawPath(path, paint);
 *              return PixelFormat.TRANSLUCENT;
 *      });
 *  });
 *  </pre>
 *
 *  <p>If the encoded image is incomplete or contains an error, or if an
 *  {@link Exception} occurs during decoding, a {@link DecodeException DecodeException}
 *  will be thrown. In some cases, the {@link ImageDecoder} may have decoded part of
 *  the image. In order to display the partial image, an
 *  {@link OnPartialImageListener OnPartialImageListener} must be passed to
 *  {@link #setOnPartialImageListener setOnPartialImageListener}. For example:
 *
 *  <pre class="prettyprint">
 *  Drawable drawable = ImageDecoder.decodeDrawable(source, (decoder, info, src) -&gt; {
 *      decoder.setOnPartialImageListener((DecodeException e) -&gt; {
 *              // Returning true indicates to create a Drawable or Bitmap even
 *              // if the whole image could not be decoded. Any remaining lines
 *              // will be blank.
 *              return true;
 *      });
 *  });
 *  </pre>
 */
public final class ImageDecoder implements AutoCloseable {
    
@hide
/** @hide **/
    public static int sApiLevel;

    
 Source of encoded image data.
 
References the data that will be used to decode a Drawable or Bitmap in decodeDrawable or decodeBitmap. Constructing a Source (with one of the overloads of createSource) can be done on any thread because the construction simply captures values. The real work is done in decodeDrawable or decodeBitmap. 
A Source object can be reused to create multiple versions of the same image. For example, to decode a full size image and its thumbnail, the same Source can be used once with no OnHeaderDecodedListener and once with an implementation of onHeaderDecoded that calls setTargetSize with smaller dimensions. One Source even used simultaneously in multiple threads.
/**
     *  Source of encoded image data.
     *
     *  <p>References the data that will be used to decode a {@link Drawable}
     *  or {@link Bitmap} in {@link #decodeDrawable decodeDrawable} or
     *  {@link #decodeBitmap decodeBitmap}. Constructing a {@code Source} (with
     *  one of the overloads of {@code createSource}) can be done on any thread
     *  because the construction simply captures values. The real work is done
     *  in {@link #decodeDrawable decodeDrawable} or {@link #decodeBitmap decodeBitmap}.
     *
     *  <p>A {@code Source} object can be reused to create multiple versions of the
     *  same image. For example, to decode a full size image and its thumbnail,
     *  the same {@code Source} can be used once with no
     *  {@link OnHeaderDecodedListener OnHeaderDecodedListener} and once with an
     *  implementation of {@link OnHeaderDecodedListener#onHeaderDecoded onHeaderDecoded}
     *  that calls {@link #setTargetSize} with smaller dimensions. One {@code Source}
     *  even used simultaneously in multiple threads.</p>
     */
    public static abstract class Source {
        private Source() {}

        /* @hide */
        @Nullable
        Resources getResources() { return null; }

        /* @hide */
        int getDensity() { return Bitmap.DENSITY_NONE; }

        /* @hide */
        final int computeDstDensity() {
            Resources res = getResources();
            if (res == null) {
                return Bitmap.getDefaultDensity();
            }

            return res.getDisplayMetrics().densityDpi;
        }

        /* @hide */
        @NonNull
        abstract ImageDecoder createImageDecoder() throws IOException;
    };

    private static class ByteArraySource extends Source {
        ByteArraySource(@NonNull byte[] data, int offset, int length) {
            mData = data;
            mOffset = offset;
            mLength = length;
        };
        private final byte[] mData;
        private final int    mOffset;
        private final int    mLength;

        @Override
        public ImageDecoder createImageDecoder() throws IOException {
            return nCreate(mData, mOffset, mLength, this);
        }
    }

    private static class ByteBufferSource extends Source {
        ByteBufferSource(@NonNull ByteBuffer buffer) {
            mBuffer = buffer;
        }
        private final ByteBuffer mBuffer;

        @Override
        public ImageDecoder createImageDecoder() throws IOException {
            if (!mBuffer.isDirect() && mBuffer.hasArray()) {
                int offset = mBuffer.arrayOffset() + mBuffer.position();
                int length = mBuffer.limit() - mBuffer.position();
                return nCreate(mBuffer.array(), offset, length, this);
            }
            ByteBuffer buffer = mBuffer.slice();
            return nCreate(buffer, buffer.position(), buffer.limit(), this);
        }
    }

    private static class ContentResolverSource extends Source {
        ContentResolverSource(@NonNull ContentResolver resolver, @NonNull Uri uri,
                @Nullable Resources res) {
            mResolver = resolver;
            mUri = uri;
            mResources = res;
        }

        private final ContentResolver mResolver;
        private final Uri mUri;
        private final Resources mResources;

        @Nullable
        Resources getResources() { return mResources; }

        @Override
        public ImageDecoder createImageDecoder() throws IOException {
            AssetFileDescriptor assetFd = null;
            try {
                if (mUri.getScheme() == ContentResolver.SCHEME_CONTENT) {
                    assetFd = mResolver.openTypedAssetFileDescriptor(mUri,
                            "image/*", null);
                } else {
                    assetFd = mResolver.openAssetFileDescriptor(mUri, "r");
                }
            } catch (FileNotFoundException e) {
                // Some images cannot be opened as AssetFileDescriptors (e.g.
                // bmp, ico). Open them as InputStreams.
                InputStream is = mResolver.openInputStream(mUri);
                if (is == null) {
                    throw new FileNotFoundException(mUri.toString());
                }

                return createFromStream(is, true, this);
            }

            final FileDescriptor fd = assetFd.getFileDescriptor();
            final long offset = assetFd.getStartOffset();

            ImageDecoder decoder = null;
            try {
                try {
                    Os.lseek(fd, offset, SEEK_SET);
                    decoder = nCreate(fd, this);
                } catch (ErrnoException e) {
                    decoder = createFromStream(new FileInputStream(fd), true, this);
                }
            } finally {
                if (decoder == null) {
                    IoUtils.closeQuietly(assetFd);
                } else {
                    decoder.mAssetFd = assetFd;
                }
            }
            return decoder;
        }
    }

    @NonNull
    private static ImageDecoder createFromFile(@NonNull File file,
            @NonNull Source source) throws IOException {
        FileInputStream stream = new FileInputStream(file);
        FileDescriptor fd = stream.getFD();
        try {
            Os.lseek(fd, 0, SEEK_CUR);
        } catch (ErrnoException e) {
            return createFromStream(stream, true, source);
        }

        ImageDecoder decoder = null;
        try {
            decoder = nCreate(fd, source);
        } finally {
            if (decoder == null) {
                IoUtils.closeQuietly(stream);
            } else {
                decoder.mInputStream = stream;
                decoder.mOwnsInputStream = true;
            }
        }
        return decoder;
    }

    @NonNull
    private static ImageDecoder createFromStream(@NonNull InputStream is,
            boolean closeInputStream, Source source) throws IOException {
        // Arbitrary size matches BitmapFactory.
        byte[] storage = new byte[16 * 1024];
        ImageDecoder decoder = null;
        try {
            decoder = nCreate(is, storage, source);
        } finally {
            if (decoder == null) {
                if (closeInputStream) {
                    IoUtils.closeQuietly(is);
                }
            } else {
                decoder.mInputStream = is;
                decoder.mOwnsInputStream = closeInputStream;
                decoder.mTempStorage = storage;
            }
        }

        return decoder;
    }

    
For backwards compatibility, this does *not* close the InputStream.
Further, unlike other Sources, this one is not reusable.
/**
     * For backwards compatibility, this does *not* close the InputStream.
     *
     * Further, unlike other Sources, this one is not reusable.
     */
    private static class InputStreamSource extends Source {
        InputStreamSource(Resources res, InputStream is, int inputDensity) {
            if (is == null) {
                throw new IllegalArgumentException("The InputStream cannot be null");
            }
            mResources = res;
            mInputStream = is;
            mInputDensity = res != null ? inputDensity : Bitmap.DENSITY_NONE;
        }

        final Resources mResources;
        InputStream mInputStream;
        final int mInputDensity;

        @Override
        public Resources getResources() { return mResources; }

        @Override
        public int getDensity() { return mInputDensity; }

        @Override
        public ImageDecoder createImageDecoder() throws IOException {

            synchronized (this) {
                if (mInputStream == null) {
                    throw new IOException("Cannot reuse InputStreamSource");
                }
                InputStream is = mInputStream;
                mInputStream = null;
                return createFromStream(is, false, this);
            }
        }
    }

    
Takes ownership of the AssetInputStream.
@hide
/**
     * Takes ownership of the AssetInputStream.
     *
     * @hide
     */
    public static class AssetInputStreamSource extends Source {
        public AssetInputStreamSource(@NonNull AssetInputStream ais,
                @NonNull Resources res, @NonNull TypedValue value) {
            mAssetInputStream = ais;
            mResources = res;

            if (value.density == TypedValue.DENSITY_DEFAULT) {
                mDensity = DisplayMetrics.DENSITY_DEFAULT;
            } else if (value.density != TypedValue.DENSITY_NONE) {
                mDensity = value.density;
            } else {
                mDensity = Bitmap.DENSITY_NONE;
            }
        }

        private AssetInputStream mAssetInputStream;
        private final Resources  mResources;
        private final int        mDensity;

        @Override
        public Resources getResources() { return mResources; }

        @Override
        public int getDensity() {
            return mDensity;
        }

        @Override
        public ImageDecoder createImageDecoder() throws IOException {
            synchronized (this) {
                if (mAssetInputStream == null) {
                    throw new IOException("Cannot reuse AssetInputStreamSource");
                }
                AssetInputStream ais = mAssetInputStream;
                mAssetInputStream = null;
                return createFromAsset(ais, this);
            }
        }
    }

    private static class ResourceSource extends Source {
        ResourceSource(@NonNull Resources res, int resId) {
            mResources = res;
            mResId = resId;
            mResDensity = Bitmap.DENSITY_NONE;
        }

        final Resources mResources;
        final int       mResId;
        int             mResDensity;
        private Object  mLock = new Object();

        @Override
        public Resources getResources() { return mResources; }

        @Override
        public int getDensity() {
            synchronized (mLock) {
                return mResDensity;
            }
        }

        @Override
        public ImageDecoder createImageDecoder() throws IOException {
            TypedValue value = new TypedValue();
            // This is just used in order to access the underlying Asset and
            // keep it alive.
            InputStream is = mResources.openRawResource(mResId, value);

            synchronized (mLock) {
                if (value.density == TypedValue.DENSITY_DEFAULT) {
                    mResDensity = DisplayMetrics.DENSITY_DEFAULT;
                } else if (value.density != TypedValue.DENSITY_NONE) {
                    mResDensity = value.density;
                }
            }

            return createFromAsset((AssetInputStream) is, this);
        }
    }

    
 ImageDecoder will own the AssetInputStream.
/**
     *  ImageDecoder will own the AssetInputStream.
     */
    private static ImageDecoder createFromAsset(AssetInputStream ais,
            Source source) throws IOException {
        ImageDecoder decoder = null;
        try {
            long asset = ais.getNativeAsset();
            decoder = nCreate(asset, source);
        } finally {
            if (decoder == null) {
                IoUtils.closeQuietly(ais);
            } else {
                decoder.mInputStream = ais;
                decoder.mOwnsInputStream = true;
            }
        }
        return decoder;
    }

    private static class AssetSource extends Source {
        AssetSource(@NonNull AssetManager assets, @NonNull String fileName) {
            mAssets = assets;
            mFileName = fileName;
        }

        private final AssetManager mAssets;
        private final String mFileName;

        @Override
        public ImageDecoder createImageDecoder() throws IOException {
            InputStream is = mAssets.open(mFileName);
            return createFromAsset((AssetInputStream) is, this);
        }
    }

    private static class FileSource extends Source {
        FileSource(@NonNull File file) {
            mFile = file;
        }

        private final File mFile;

        @Override
        public ImageDecoder createImageDecoder() throws IOException {
            return createFromFile(mFile, this);
        }
    }

    
 Information about an encoded image.
/**
     *  Information about an encoded image.
     */
    public static class ImageInfo {
        private final Size mSize;
        private ImageDecoder mDecoder;

        private ImageInfo(@NonNull ImageDecoder decoder) {
            mSize = new Size(decoder.mWidth, decoder.mHeight);
            mDecoder = decoder;
        }

        
Size of the image, without scaling or cropping.
/**
         * Size of the image, without scaling or cropping.
         */
        @NonNull
        public Size getSize() {
            return mSize;
        }

        
The mimeType of the image.
/**
         * The mimeType of the image.
         */
        @NonNull
        public String getMimeType() {
            return mDecoder.getMimeType();
        }

        
Whether the image is animated.
If true, decodeDrawable will return an AnimatedImageDrawable.
/**
         * Whether the image is animated.
         *
         * <p>If {@code true}, {@link #decodeDrawable decodeDrawable} will
         * return an {@link AnimatedImageDrawable}.</p>
         */
        public boolean isAnimated() {
            return mDecoder.mAnimated;
        }

        
If known, the color space the decoded bitmap will have. Note that the output color space is not guaranteed to be the color space the bitmap is encoded with. If not known (when the config is Config.ALPHA_8 for instance), or there is an error, it is set to null. /**
         * If known, the color space the decoded bitmap will have. Note that the
         * output color space is not guaranteed to be the color space the bitmap
         * is encoded with. If not known (when the config is
         * {@link Bitmap.Config#ALPHA_8} for instance), or there is an error,
         * it is set to null.
         */
        @Nullable
        public ColorSpace getColorSpace() {
            return mDecoder.getColorSpace();
        }
    };

    
@removed
Deprecated:
Subsumed by DecodeException./** @removed
     * @deprecated Subsumed by {@link #DecodeException}.
     */
    @Deprecated
    public static class IncompleteException extends IOException {};

    
 Interface for changing the default settings of a decode.
 
Supply an instance to decodeDrawable or decodeBitmap, which will call onHeaderDecoded (in the same thread) once the size is known. The implementation of onHeaderDecoded can then change the decode settings as desired. /**
     *  Interface for changing the default settings of a decode.
     *
     *  <p>Supply an instance to
     *  {@link #decodeDrawable(Source, OnHeaderDecodedListener) decodeDrawable}
     *  or {@link #decodeBitmap(Source, OnHeaderDecodedListener) decodeBitmap},
     *  which will call {@link OnHeaderDecodedListener#onHeaderDecoded onHeaderDecoded}
     *  (in the same thread) once the size is known. The implementation of
     *  {@link OnHeaderDecodedListener#onHeaderDecoded onHeaderDecoded} can then
     *  change the decode settings as desired.
     */
    public static interface OnHeaderDecodedListener {
        
 Called by ImageDecoder when the header has been decoded and the image size is known. @param decoder the object performing the decode, for changing its default settings. @param info information about the encoded image. @param source object that created decoder. /**
         *  Called by {@link ImageDecoder} when the header has been decoded and
         *  the image size is known.
         *
         *  @param decoder the object performing the decode, for changing
         *      its default settings.
         *  @param info information about the encoded image.
         *  @param source object that created {@code decoder}.
         */
        public void onHeaderDecoded(@NonNull ImageDecoder decoder,
                @NonNull ImageInfo info, @NonNull Source source);

    };

    
@removed
Deprecated:
Replaced by #DecodeException#SOURCE_EXCEPTION./** @removed
     * @deprecated Replaced by {@link #DecodeException#SOURCE_EXCEPTION}.
     */
    @Deprecated
    public static final int ERROR_SOURCE_EXCEPTION  = 1;

    
@removed
Deprecated:
Replaced by #DecodeException#SOURCE_INCOMPLETE./** @removed
     * @deprecated Replaced by {@link #DecodeException#SOURCE_INCOMPLETE}.
     */
    @Deprecated
    public static final int ERROR_SOURCE_INCOMPLETE = 2;

    
@removed
Deprecated:
Replaced by #DecodeException#SOURCE_MALFORMED_DATA./** @removed
     * @deprecated Replaced by {@link #DecodeException#SOURCE_MALFORMED_DATA}.
     */
    @Deprecated
    public static final int ERROR_SOURCE_ERROR      = 3;

    
 Information about an interrupted decode.
/**
     *  Information about an interrupted decode.
     */
    public static final class DecodeException extends IOException {
        
 An Exception was thrown reading the Source. /**
         *  An Exception was thrown reading the {@link Source}.
         */
        public static final int SOURCE_EXCEPTION  = 1;

        
 The encoded data was incomplete.
/**
         *  The encoded data was incomplete.
         */
        public static final int SOURCE_INCOMPLETE = 2;

        
 The encoded data contained an error.
/**
         *  The encoded data contained an error.
         */
        public static final int SOURCE_MALFORMED_DATA      = 3;

        
@hide
/** @hide **/
        @Retention(SOURCE)
        @IntDef(value = { SOURCE_EXCEPTION, SOURCE_INCOMPLETE, SOURCE_MALFORMED_DATA },
                prefix = {"SOURCE_"})
        public @interface Error {};

        @Error final int mError;
        @NonNull final Source mSource;

        DecodeException(@Error int error, @Nullable Throwable cause, @NonNull Source source) {
            super(errorMessage(error, cause), cause);
            mError = error;
            mSource = source;
        }

        
Private method called by JNI.
/**
         * Private method called by JNI.
         */
        @SuppressWarnings("unused")
        DecodeException(@Error int error, @Nullable String msg, @Nullable Throwable cause,
                @NonNull Source source) {
            super(msg + errorMessage(error, cause), cause);
            mError = error;
            mSource = source;
        }

        
 Retrieve the reason that decoding was interrupted.
 
If the error is SOURCE_EXCEPTION, the underlying Throwable can be retrieved with Throwable.getCause.
/**
         *  Retrieve the reason that decoding was interrupted.
         *
         *  <p>If the error is {@link #SOURCE_EXCEPTION}, the underlying
         *  {@link java.lang.Throwable} can be retrieved with
         *  {@link java.lang.Throwable#getCause}.</p>
         */
        @Error
        public int getError() {
            return mError;
        }

        
 Retrieve the Source that was interrupted. 
This can be used for equality checking to find the Source which
 failed to completely decode.
/**
         *  Retrieve the {@link Source Source} that was interrupted.
         *
         *  <p>This can be used for equality checking to find the Source which
         *  failed to completely decode.</p>
         */
        @NonNull
        public Source getSource() {
            return mSource;
        }

        private static String errorMessage(@Error int error, @Nullable Throwable cause) {
            switch (error) {
                case SOURCE_EXCEPTION:
                    return "Exception in input: " + cause;
                case SOURCE_INCOMPLETE:
                    return "Input was incomplete.";
                case SOURCE_MALFORMED_DATA:
                    return "Input contained an error.";
                default:
                    return "";
            }
        }
    }

    
 Interface for inspecting a DecodeException and potentially preventing it from being thrown. 
If an instance is passed to setOnPartialImageListener, a DecodeException that would otherwise have been thrown can be inspected inside onPartialImage. If onPartialImage returns true, a partial image will be created. /**
     *  Interface for inspecting a {@link DecodeException DecodeException}
     *  and potentially preventing it from being thrown.
     *
     *  <p>If an instance is passed to
     *  {@link #setOnPartialImageListener setOnPartialImageListener}, a
     *  {@link DecodeException DecodeException} that would otherwise have been
     *  thrown can be inspected inside
     *  {@link OnPartialImageListener#onPartialImage onPartialImage}.
     *  If {@link OnPartialImageListener#onPartialImage onPartialImage} returns
     *  {@code true}, a partial image will be created.
     */
    public static interface OnPartialImageListener {
        
 Called by ImageDecoder when there is only a partial image to display. 
If decoding is interrupted after having decoded a partial image, this method will be called. The implementation can inspect the DecodeException and optionally finish the rest of the decode creation process to create a partial Drawable or Bitmap. @param exception exception containing information about the decode interruption. @return true to create and return a Drawable or Bitmap with partial data. false (which is the default) to abort the decode and throw e. Any undecoded lines in the image will be blank. /**
         *  Called by {@link ImageDecoder} when there is only a partial image to
         *  display.
         *
         *  <p>If decoding is interrupted after having decoded a partial image,
         *  this method will be called. The implementation can inspect the
         *  {@link DecodeException DecodeException} and optionally finish the
         *  rest of the decode creation process to create a partial {@link Drawable}
         *  or {@link Bitmap}.
         *
         *  @param exception exception containing information about the
         *      decode interruption.
         *  @return {@code true} to create and return a {@link Drawable} or
         *      {@link Bitmap} with partial data. {@code false} (which is the
         *      default) to abort the decode and throw {@code e}. Any undecoded
         *      lines in the image will be blank.
         */
        boolean onPartialImage(@NonNull DecodeException exception);
    };

    // Fields
    private long          mNativePtr;
    private final int     mWidth;
    private final int     mHeight;
    private final boolean mAnimated;
    private final boolean mIsNinePatch;

    private int        mDesiredWidth;
    private int        mDesiredHeight;
    private int        mAllocator = ALLOCATOR_DEFAULT;
    private boolean    mUnpremultipliedRequired = false;
    private boolean    mMutable = false;
    private boolean    mConserveMemory = false;
    private boolean    mDecodeAsAlphaMask = false;
    private ColorSpace mDesiredColorSpace = null;
    private Rect       mCropRect;
    private Rect       mOutPaddingRect;
    private Source     mSource;

    private PostProcessor          mPostProcessor;
    private OnPartialImageListener mOnPartialImageListener;

    // Objects for interacting with the input.
    private InputStream         mInputStream;
    private boolean             mOwnsInputStream;
    private byte[]              mTempStorage;
    private AssetFileDescriptor mAssetFd;
    private final AtomicBoolean mClosed = new AtomicBoolean();
    private final CloseGuard    mCloseGuard = CloseGuard.get();

    
Private constructor called by JNI. close must be called after decoding to delete native resources. /**
     * Private constructor called by JNI. {@link #close} must be
     * called after decoding to delete native resources.
     */
    @SuppressWarnings("unused")
    private ImageDecoder(long nativePtr, int width, int height,
            boolean animated, boolean isNinePatch) {
        mNativePtr = nativePtr;
        mWidth = width;
        mHeight = height;
        mDesiredWidth = width;
        mDesiredHeight = height;
        mAnimated = animated;
        mIsNinePatch = isNinePatch;
        mCloseGuard.open("close");
    }

    @Override
    protected void finalize() throws Throwable {
        try {
            if (mCloseGuard != null) {
                mCloseGuard.warnIfOpen();
            }

            // Avoid closing these in finalizer.
            mInputStream = null;
            mAssetFd = null;

            close();
        } finally {
            super.finalize();
        }
    }

    
Create a new Source from a resource. 
Params:
res – the Resources object containing the image data.
resId – resource ID of the image data.
Returns:
a new Source object, which can be passed to decodeDrawable or decodeBitmap./**
     * Create a new {@link Source Source} from a resource.
     *
     * @param res the {@link Resources} object containing the image data.
     * @param resId resource ID of the image data.
     * @return a new Source object, which can be passed to
     *      {@link #decodeDrawable decodeDrawable} or
     *      {@link #decodeBitmap decodeBitmap}.
     */
    @AnyThread
    @NonNull
    public static Source createSource(@NonNull Resources res, int resId)
    {
        return new ResourceSource(res, resId);
    }

    
Create a new Source from a Uri. 
Accepts the following URI schemes:

content (ContentResolver.SCHEME_CONTENT)
android.resource (ContentResolver.SCHEME_ANDROID_RESOURCE)
file (ContentResolver.SCHEME_FILE)

Params:
cr – to retrieve from.
uri – of the image file.
Returns:
a new Source object, which can be passed to decodeDrawable or decodeBitmap./**
     * Create a new {@link Source Source} from a {@link android.net.Uri}.
     *
     * <h5>Accepts the following URI schemes:</h5>
     * <ul>
     * <li>content ({@link ContentResolver#SCHEME_CONTENT})</li>
     * <li>android.resource ({@link ContentResolver#SCHEME_ANDROID_RESOURCE})</li>
     * <li>file ({@link ContentResolver#SCHEME_FILE})</li>
     * </ul>
     *
     * @param cr to retrieve from.
     * @param uri of the image file.
     * @return a new Source object, which can be passed to
     *      {@link #decodeDrawable decodeDrawable} or
     *      {@link #decodeBitmap decodeBitmap}.
     */
    @AnyThread
    @NonNull
    public static Source createSource(@NonNull ContentResolver cr,
            @NonNull Uri uri) {
        return new ContentResolverSource(cr, uri, null);
    }

    
Provide Resources for density scaling.
@hide
/**
     * Provide Resources for density scaling.
     *
     * @hide
     */
    @AnyThread
    @NonNull
    public static Source createSource(@NonNull ContentResolver cr,
            @NonNull Uri uri, @Nullable Resources res) {
        return new ContentResolverSource(cr, uri, res);
    }

    
Create a new Source from a file in the "assets" directory. /**
     * Create a new {@link Source Source} from a file in the "assets" directory.
     */
    @AnyThread
    @NonNull
    public static Source createSource(@NonNull AssetManager assets, @NonNull String fileName) {
        return new AssetSource(assets, fileName);
    }

    
Create a new Source from a byte array. 
Params:
data – byte array of compressed image data.
offset – offset into data for where the decoder should begin
     parsing.
length – number of bytes, beginning at offset, to parse.
Throws:
NullPointerException – if data is null.
ArrayIndexOutOfBoundsException – if offset and length are
     not within data.
Returns:
a new Source object, which can be passed to decodeDrawable or decodeBitmap.
@hide
/**
     * Create a new {@link Source Source} from a byte array.
     *
     * @param data byte array of compressed image data.
     * @param offset offset into data for where the decoder should begin
     *      parsing.
     * @param length number of bytes, beginning at offset, to parse.
     * @return a new Source object, which can be passed to
     *      {@link #decodeDrawable decodeDrawable} or
     *      {@link #decodeBitmap decodeBitmap}.
     * @throws NullPointerException if data is null.
     * @throws ArrayIndexOutOfBoundsException if offset and length are
     *      not within data.
     * @hide
     */
    @AnyThread
    @NonNull
    public static Source createSource(@NonNull byte[] data, int offset,
            int length) throws ArrayIndexOutOfBoundsException {
        if (data == null) {
            throw new NullPointerException("null byte[] in createSource!");
        }
        if (offset < 0 || length < 0 || offset >= data.length ||
                offset + length > data.length) {
            throw new ArrayIndexOutOfBoundsException(
                    "invalid offset/length!");
        }
        return new ByteArraySource(data, offset, length);
    }

    
See #createSource(byte[], int, int).
@hide
/**
     * See {@link #createSource(byte[], int, int).
     * @hide
     */
    @AnyThread
    @NonNull
    public static Source createSource(@NonNull byte[] data) {
        return createSource(data, 0, data.length);
    }

    
Create a new Source from a ByteBuffer. 
Decoding will start from buffer.position(). The position of buffer will not be affected.
Note: If this Source is passed to decodeDrawable, and the encoded image is animated, the returned AnimatedImageDrawable will continue reading from the buffer, so its contents must not be modified, even after the AnimatedImageDrawable is returned. buffer's contents should never be modified during decode.
Returns:
a new Source object, which can be passed to decodeDrawable or decodeBitmap./**
     * Create a new {@link Source Source} from a {@link java.nio.ByteBuffer}.
     *
     * <p>Decoding will start from {@link java.nio.ByteBuffer#position() buffer.position()}.
     * The position of {@code buffer} will not be affected.</p>
     *
     * <p>Note: If this {@code Source} is passed to {@link #decodeDrawable decodeDrawable},
     * and the encoded image is animated, the returned {@link AnimatedImageDrawable}
     * will continue reading from the {@code buffer}, so its contents must not
     * be modified, even after the {@code AnimatedImageDrawable} is returned.
     * {@code buffer}'s contents should never be modified during decode.</p>
     *
     * @return a new Source object, which can be passed to
     *      {@link #decodeDrawable decodeDrawable} or
     *      {@link #decodeBitmap decodeBitmap}.
     */
    @AnyThread
    @NonNull
    public static Source createSource(@NonNull ByteBuffer buffer) {
        return new ByteBufferSource(buffer);
    }

    
Internal API used to generate bitmaps for use by Drawables (i.e. BitmapDrawable)
Unlike other Sources, this one cannot be reused.
@hide
/**
     * Internal API used to generate bitmaps for use by Drawables (i.e. BitmapDrawable)
     *
     * <p>Unlike other Sources, this one cannot be reused.</p>
     *
     * @hide
     */
    @AnyThread
    @NonNull
    public static Source createSource(Resources res, InputStream is) {
        return new InputStreamSource(res, is, Bitmap.getDefaultDensity());
    }

    
Internal API used to generate bitmaps for use by Drawables (i.e. BitmapDrawable)
Unlike other Sources, this one cannot be reused.
@hide
/**
     * Internal API used to generate bitmaps for use by Drawables (i.e. BitmapDrawable)
     *
     * <p>Unlike other Sources, this one cannot be reused.</p>
     *
     * @hide
     */
    @AnyThread
    @TestApi
    @NonNull
    public static Source createSource(Resources res, InputStream is, int density) {
        return new InputStreamSource(res, is, density);
    }

    
Create a new Source from a File. 
Returns:
a new Source object, which can be passed to decodeDrawable or decodeBitmap./**
     * Create a new {@link Source Source} from a {@link java.io.File}.
     *
     * @return a new Source object, which can be passed to
     *      {@link #decodeDrawable decodeDrawable} or
     *      {@link #decodeBitmap decodeBitmap}.
     */
    @AnyThread
    @NonNull
    public static Source createSource(@NonNull File file) {
        return new FileSource(file);
    }

    
 Return the width and height of a given sample size.
 
This takes an input that functions like Options.inSampleSize. It returns a width and height that can be achieved by sampling the encoded image. Other widths and heights may be supported, but will require an additional (internal) scaling step. Such internal scaling is *not* supported with setUnpremultipliedRequired set to true.
 @param sampleSize Sampling rate of the encoded image. @return Size of the width and height after sampling. @hide /**
     *  Return the width and height of a given sample size.
     *
     *  <p>This takes an input that functions like
     *  {@link BitmapFactory.Options#inSampleSize}. It returns a width and
     *  height that can be achieved by sampling the encoded image. Other widths
     *  and heights may be supported, but will require an additional (internal)
     *  scaling step. Such internal scaling is *not* supported with
     *  {@link #setUnpremultipliedRequired} set to {@code true}.</p>
     *
     *  @param sampleSize Sampling rate of the encoded image.
     *  @return {@link android.util.Size} of the width and height after
     *      sampling.
     *
     *  @hide
     */
    @NonNull
    public Size getSampledSize(int sampleSize) {
        if (sampleSize <= 0) {
            throw new IllegalArgumentException("sampleSize must be positive! "
                    + "provided " + sampleSize);
        }
        if (mNativePtr == 0) {
            throw new IllegalStateException("ImageDecoder is closed!");
        }

        return nGetSampledSize(mNativePtr, sampleSize);
    }

    // Modifiers
    
@removed
Deprecated:
Renamed to setTargetSize./** @removed
     * @deprecated Renamed to {@link #setTargetSize}.
     */
    @Deprecated
    public ImageDecoder setResize(int width, int height) {
        this.setTargetSize(width, height);
        return this;
    }

    
 Specify the size of the output Drawable or Bitmap. 
By default, the output size will match the size of the encoded image, which can be retrieved from the ImageInfo in onHeaderDecoded.
 
This will sample or scale the output to an arbitrary size that may
 be smaller or larger than the encoded size.
 
Only the last call to this or setTargetSampleSize is respected.
 
Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.
 @param width width in pixels of the output, must be greater than 0
 @param height height in pixels of the output, must be greater than 0
/**
     *  Specify the size of the output {@link Drawable} or {@link Bitmap}.
     *
     *  <p>By default, the output size will match the size of the encoded
     *  image, which can be retrieved from the {@link ImageInfo ImageInfo} in
     *  {@link OnHeaderDecodedListener#onHeaderDecoded onHeaderDecoded}.</p>
     *
     *  <p>This will sample or scale the output to an arbitrary size that may
     *  be smaller or larger than the encoded size.</p>
     *
     *  <p>Only the last call to this or {@link #setTargetSampleSize} is
     *  respected.</p>
     *
     *  <p>Like all setters on ImageDecoder, this must be called inside
     *  {@link OnHeaderDecodedListener#onHeaderDecoded onHeaderDecoded}.</p>
     *
     *  @param width width in pixels of the output, must be greater than 0
     *  @param height height in pixels of the output, must be greater than 0
     */
    public void setTargetSize(@Px @IntRange(from = 1) int width,
                              @Px @IntRange(from = 1) int height) {
        if (width <= 0 || height <= 0) {
            throw new IllegalArgumentException("Dimensions must be positive! "
                    + "provided (" + width + ", " + height + ")");
        }

        mDesiredWidth = width;
        mDesiredHeight = height;
    }

    
@removed
Deprecated:
Renamed to setTargetSampleSize./** @removed
     * @deprecated Renamed to {@link #setTargetSampleSize}.
     */
    @Deprecated
    public ImageDecoder setResize(int sampleSize) {
        this.setTargetSampleSize(sampleSize);
        return this;
    }

    private int getTargetDimension(int original, int sampleSize, int computed) {
        // Sampling will never result in a smaller size than 1.
        if (sampleSize >= original) {
            return 1;
        }

        // Use integer divide to find the desired size. If that is what
        // getSampledSize computed, that is the size to use.
        int target = original / sampleSize;
        if (computed == target) {
            return computed;
        }

        // If sampleSize does not divide evenly into original, the decoder
        // may round in either direction. It just needs to get a result that
        // is close.
        int reverse = computed * sampleSize;
        if (Math.abs(reverse - original) < sampleSize) {
            // This is the size that can be decoded most efficiently.
            return computed;
        }

        // The decoder could not get close (e.g. it is a DNG image).
        return target;
    }

    
 Set the target size with a sampleSize.
 
By default, the output size will match the size of the encoded image, which can be retrieved from the ImageInfo in onHeaderDecoded.
 
Requests the decoder to subsample the original image, returning a smaller image to save memory. The sampleSize is the number of pixels in either dimension that correspond to a single pixel in the output. For example, sampleSize == 4 returns an image that is 1/4 the width/height of the original, and 1/16 the number of pixels.
 
Must be greater than or equal to 1.
 
This has the same effect as calling setTargetSize with dimensions based on the sampleSize. Unlike dividing the original width and height by the sampleSize manually, calling this method allows ImageDecoder to round in the direction that it can do most efficiently.
 
Only the last call to this or setTargetSize is respected.
 
Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.
 @param sampleSize sampling rate of the encoded image.
/**
     *  Set the target size with a sampleSize.
     *
     *  <p>By default, the output size will match the size of the encoded
     *  image, which can be retrieved from the {@link ImageInfo ImageInfo} in
     *  {@link OnHeaderDecodedListener#onHeaderDecoded onHeaderDecoded}.</p>
     *
     *  <p>Requests the decoder to subsample the original image, returning a
     *  smaller image to save memory. The {@code sampleSize} is the number of pixels
     *  in either dimension that correspond to a single pixel in the output.
     *  For example, {@code sampleSize == 4} returns an image that is 1/4 the
     *  width/height of the original, and 1/16 the number of pixels.</p>
     *
     *  <p>Must be greater than or equal to 1.</p>
     *
     *  <p>This has the same effect as calling {@link #setTargetSize} with
     *  dimensions based on the {@code sampleSize}. Unlike dividing the original
     *  width and height by the {@code sampleSize} manually, calling this method
     *  allows {@code ImageDecoder} to round in the direction that it can do most
     *  efficiently.</p>
     *
     *  <p>Only the last call to this or {@link #setTargetSize} is respected.</p>
     *
     *  <p>Like all setters on ImageDecoder, this must be called inside
     *  {@link OnHeaderDecodedListener#onHeaderDecoded onHeaderDecoded}.</p>
     *
     *  @param sampleSize sampling rate of the encoded image.
     */
    public void setTargetSampleSize(@IntRange(from = 1) int sampleSize) {
        Size size = this.getSampledSize(sampleSize);
        int targetWidth = getTargetDimension(mWidth, sampleSize, size.getWidth());
        int targetHeight = getTargetDimension(mHeight, sampleSize, size.getHeight());
        this.setTargetSize(targetWidth, targetHeight);
    }

    private boolean requestedResize() {
        return mWidth != mDesiredWidth || mHeight != mDesiredHeight;
    }

    // These need to stay in sync with ImageDecoder.cpp's Allocator enum.
    
 Use the default allocation for the pixel memory. Will typically result in a Config.HARDWARE allocation, but may be software for small images. In addition, this will switch to software when HARDWARE is incompatible, e.g. setMutableRequired(true) or setDecodeAsAlphaMaskEnabled(true). /**
     *  Use the default allocation for the pixel memory.
     *
     *  Will typically result in a {@link Bitmap.Config#HARDWARE}
     *  allocation, but may be software for small images. In addition, this will
     *  switch to software when HARDWARE is incompatible, e.g.
     *  {@link #setMutableRequired setMutableRequired(true)} or
     *  {@link #setDecodeAsAlphaMaskEnabled setDecodeAsAlphaMaskEnabled(true)}.
     */
    public static final int ALLOCATOR_DEFAULT = 0;

    
 Use a software allocation for the pixel memory.
 
Useful for drawing to a software Canvas or for accessing the pixels on the final output. /**
     *  Use a software allocation for the pixel memory.
     *
     *  <p>Useful for drawing to a software {@link Canvas} or for
     *  accessing the pixels on the final output.
     */
    public static final int ALLOCATOR_SOFTWARE = 1;

    
 Use shared memory for the pixel memory.
 
Useful for sharing across processes.
/**
     *  Use shared memory for the pixel memory.
     *
     *  <p>Useful for sharing across processes.
     */
    public static final int ALLOCATOR_SHARED_MEMORY = 2;

    
 Require a Config.HARDWARE Bitmap. 
When this is combined with incompatible options, like setMutableRequired(true) or setDecodeAsAlphaMaskEnabled(true), decodeDrawable or decodeBitmap will throw an IllegalStateException. /**
     *  Require a {@link Bitmap.Config#HARDWARE} {@link Bitmap}.
     *
     *  <p>When this is combined with incompatible options, like
     *  {@link #setMutableRequired setMutableRequired(true)} or
     *  {@link #setDecodeAsAlphaMaskEnabled setDecodeAsAlphaMaskEnabled(true)},
     *  {@link #decodeDrawable decodeDrawable} or {@link #decodeBitmap decodeBitmap}
     *  will throw an {@link java.lang.IllegalStateException}.
     */
    public static final int ALLOCATOR_HARDWARE = 3;

    
@hide
/** @hide **/
    @Retention(SOURCE)
    @IntDef(value = { ALLOCATOR_DEFAULT, ALLOCATOR_SOFTWARE,
              ALLOCATOR_SHARED_MEMORY, ALLOCATOR_HARDWARE },
              prefix = {"ALLOCATOR_"})
    public @interface Allocator {};

    
 Choose the backing for the pixel memory.
 
This is ignored for animated drawables.
 
Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.
 @param allocator Type of allocator to use.
/**
     *  Choose the backing for the pixel memory.
     *
     *  <p>This is ignored for animated drawables.</p>
     *
     *  <p>Like all setters on ImageDecoder, this must be called inside
     *  {@link OnHeaderDecodedListener#onHeaderDecoded onHeaderDecoded}.</p>
     *
     *  @param allocator Type of allocator to use.
     */
    public void setAllocator(@Allocator int allocator) {
        if (allocator < ALLOCATOR_DEFAULT || allocator > ALLOCATOR_HARDWARE) {
            throw new IllegalArgumentException("invalid allocator " + allocator);
        }
        mAllocator = allocator;
    }

    
 Return the allocator for the pixel memory.
/**
     *  Return the allocator for the pixel memory.
     */
    @Allocator
    public int getAllocator() {
        return mAllocator;
    }

    
 Specify whether the Bitmap should have unpremultiplied pixels. 
By default, ImageDecoder will create a Bitmap with premultiplied pixels, which is required for drawing with the View system (i.e. to a Canvas). Calling this method with a value of true will result in decodeBitmap returning a Bitmap with unpremultiplied pixels. See Bitmap.isPremultiplied(). This is incompatible with decodeDrawable; attempting to decode an unpremultiplied Drawable will throw an IllegalStateException. 
 
Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.
/**
     *  Specify whether the {@link Bitmap} should have unpremultiplied pixels.
     *
     *  <p>By default, ImageDecoder will create a {@link Bitmap} with
     *  premultiplied pixels, which is required for drawing with the
     *  {@link android.view.View} system (i.e. to a {@link Canvas}). Calling
     *  this method with a value of {@code true} will result in
     *  {@link #decodeBitmap} returning a {@link Bitmap} with unpremultiplied
     *  pixels. See {@link Bitmap#isPremultiplied Bitmap.isPremultiplied()}.
     *  This is incompatible with {@link #decodeDrawable decodeDrawable};
     *  attempting to decode an unpremultiplied {@link Drawable} will throw an
     *  {@link java.lang.IllegalStateException}. </p>
     *
     *  <p>Like all setters on ImageDecoder, this must be called inside
     *  {@link OnHeaderDecodedListener#onHeaderDecoded onHeaderDecoded}.</p>
     */
    public void setUnpremultipliedRequired(boolean unpremultipliedRequired) {
        mUnpremultipliedRequired = unpremultipliedRequired;
    }

    
@removed
Deprecated:
Renamed to setUnpremultipliedRequired./** @removed
     * @deprecated Renamed to {@link #setUnpremultipliedRequired}.
     */
    @Deprecated
    public ImageDecoder setRequireUnpremultiplied(boolean unpremultipliedRequired) {
        this.setUnpremultipliedRequired(unpremultipliedRequired);
        return this;
    }

    
 Return whether the Bitmap will have unpremultiplied pixels. /**
     *  Return whether the {@link Bitmap} will have unpremultiplied pixels.
     */
    public boolean isUnpremultipliedRequired() {
        return mUnpremultipliedRequired;
    }

    
@removed
Deprecated:
Renamed to isUnpremultipliedRequired./** @removed
     * @deprecated Renamed to {@link #isUnpremultipliedRequired}.
     */
    @Deprecated
    public boolean getRequireUnpremultiplied() {
        return this.isUnpremultipliedRequired();
    }

    
 Modify the image after decoding and scaling.
 
This allows adding effects prior to returning a Drawable or Bitmap. For a Drawable or an immutable Bitmap, this is the only way to process the image after decoding.
 
If combined with setTargetSize and/or setCrop, PostProcessor.onPostProcess occurs last.
 
If set on a nine-patch image, the nine-patch data is ignored.
 
For an animated image, the drawing commands drawn on the Canvas will be recorded immediately and then applied to each frame.
 
Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.
/**
     *  Modify the image after decoding and scaling.
     *
     *  <p>This allows adding effects prior to returning a {@link Drawable} or
     *  {@link Bitmap}. For a {@code Drawable} or an immutable {@code Bitmap},
     *  this is the only way to process the image after decoding.</p>
     *
     *  <p>If combined with {@link #setTargetSize} and/or {@link #setCrop},
     *  {@link PostProcessor#onPostProcess} occurs last.</p>
     *
     *  <p>If set on a nine-patch image, the nine-patch data is ignored.</p>
     *
     *  <p>For an animated image, the drawing commands drawn on the
     *  {@link Canvas} will be recorded immediately and then applied to each
     *  frame.</p>
     *
     *  <p>Like all setters on ImageDecoder, this must be called inside
     *  {@link OnHeaderDecodedListener#onHeaderDecoded onHeaderDecoded}.</p>
     *
     */
    public void setPostProcessor(@Nullable PostProcessor postProcessor) {
        mPostProcessor = postProcessor;
    }

    
 Return the PostProcessor currently set. /**
     *  Return the {@link PostProcessor} currently set.
     */
    @Nullable
    public PostProcessor getPostProcessor() {
        return mPostProcessor;
    }

    
 Set (replace) the OnPartialImageListener on this object. 
Will be called if there is an error in the input. Without one, an error will result in an Exception being thrown.
 
Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.
/**
     *  Set (replace) the {@link OnPartialImageListener} on this object.
     *
     *  <p>Will be called if there is an error in the input. Without one, an
     *  error will result in an {@code Exception} being thrown.</p>
     *
     *  <p>Like all setters on ImageDecoder, this must be called inside
     *  {@link OnHeaderDecodedListener#onHeaderDecoded onHeaderDecoded}.</p>
     *
     */
    public void setOnPartialImageListener(@Nullable OnPartialImageListener listener) {
        mOnPartialImageListener = listener;
    }

    
 Return the OnPartialImageListener currently set. /**
     *  Return the {@link OnPartialImageListener OnPartialImageListener} currently set.
     */
    @Nullable
    public OnPartialImageListener getOnPartialImageListener() {
        return mOnPartialImageListener;
    }

    
 Crop the output to subset of the (possibly) scaled image. 
subset must be contained within the size set by setTargetSize or the bounds of the image if setTargetSize was not called. Otherwise an IllegalStateException will be thrown by decodeDrawable/decodeBitmap.
 
NOT intended as a replacement for BitmapRegionDecoder.decodeRegion(). This supports all formats, but merely crops the output.
 
Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.
/**
     *  Crop the output to {@code subset} of the (possibly) scaled image.
     *
     *  <p>{@code subset} must be contained within the size set by
     *  {@link #setTargetSize} or the bounds of the image if setTargetSize was
     *  not called. Otherwise an {@link IllegalStateException} will be thrown by
     *  {@link #decodeDrawable decodeDrawable}/{@link #decodeBitmap decodeBitmap}.</p>
     *
     *  <p>NOT intended as a replacement for
     *  {@link BitmapRegionDecoder#decodeRegion BitmapRegionDecoder.decodeRegion()}.
     *  This supports all formats, but merely crops the output.</p>
     *
     *  <p>Like all setters on ImageDecoder, this must be called inside
     *  {@link OnHeaderDecodedListener#onHeaderDecoded onHeaderDecoded}.</p>
     *
     */
    public void setCrop(@Nullable Rect subset) {
        mCropRect = subset;
    }

    
 Return the cropping rectangle, if set.
/**
     *  Return the cropping rectangle, if set.
     */
    @Nullable
    public Rect getCrop() {
        return mCropRect;
    }

    
 Set a Rect for retrieving nine patch padding.
 If the image is a nine patch, this Rect will be set to the padding
 rectangle during decode. Otherwise it will not be modified.
 
Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.
 @hide
/**
     *  Set a Rect for retrieving nine patch padding.
     *
     *  If the image is a nine patch, this Rect will be set to the padding
     *  rectangle during decode. Otherwise it will not be modified.
     *
     *  <p>Like all setters on ImageDecoder, this must be called inside
     *  {@link OnHeaderDecodedListener#onHeaderDecoded onHeaderDecoded}.</p>
     *
     *  @hide
     */
    public void setOutPaddingRect(@NonNull Rect outPadding) {
        mOutPaddingRect = outPadding;
    }

    
 Specify whether the Bitmap should be mutable. 
By default, a Bitmap created by decodeBitmap will be immutable i.e. Bitmap.isMutable() returns false. This can be changed with setMutableRequired(true). 
Mutable Bitmaps are incompatible with ALLOCATOR_HARDWARE, because Config.HARDWARE Bitmaps cannot be mutable. Attempting to combine them will throw an IllegalStateException.
 
Mutable Bitmaps are also incompatible with decodeDrawable, which would require retrieving the Bitmap from the returned Drawable in order to modify. Attempting to decode a mutable Drawable will throw an IllegalStateException.
 
Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.
/**
     *  Specify whether the {@link Bitmap} should be mutable.
     *
     *  <p>By default, a {@link Bitmap} created by {@link #decodeBitmap decodeBitmap}
     *  will be immutable i.e. {@link Bitmap#isMutable() Bitmap.isMutable()} returns
     *  {@code false}. This can be changed with {@code setMutableRequired(true)}.
     *
     *  <p>Mutable Bitmaps are incompatible with {@link #ALLOCATOR_HARDWARE},
     *  because {@link Bitmap.Config#HARDWARE} Bitmaps cannot be mutable.
     *  Attempting to combine them will throw an
     *  {@link java.lang.IllegalStateException}.</p>
     *
     *  <p>Mutable Bitmaps are also incompatible with {@link #decodeDrawable decodeDrawable},
     *  which would require retrieving the Bitmap from the returned Drawable in
     *  order to modify. Attempting to decode a mutable {@link Drawable} will
     *  throw an {@link java.lang.IllegalStateException}.</p>
     *
     *  <p>Like all setters on ImageDecoder, this must be called inside
     *  {@link OnHeaderDecodedListener#onHeaderDecoded onHeaderDecoded}.</p>
     */
    public void setMutableRequired(boolean mutable) {
        mMutable = mutable;
    }

    
@removed
Deprecated:
Renamed to setMutableRequired./** @removed
     * @deprecated Renamed to {@link #setMutableRequired}.
     */
    @Deprecated
    public ImageDecoder setMutable(boolean mutable) {
        this.setMutableRequired(mutable);
        return this;
    }

    
 Return whether the decoded Bitmap will be mutable. /**
     *  Return whether the decoded {@link Bitmap} will be mutable.
     */
    public boolean isMutableRequired() {
        return mMutable;
    }

    
@removed
Deprecated:
Renamed to isMutableRequired./** @removed
     * @deprecated Renamed to {@link #isMutableRequired}.
     */
    @Deprecated
    public boolean getMutable() {
        return this.isMutableRequired();
    }

    
Save memory if possible by using a denser Config at the cost of some image quality. 
For example an opaque 8-bit image may be compressed into an Config.RGB_565 configuration, sacrificing image quality to save memory. /**
     * Save memory if possible by using a denser {@link Bitmap.Config} at the
     * cost of some image quality.
     *
     * <p>For example an opaque 8-bit image may be compressed into an
     * {@link Bitmap.Config#RGB_565} configuration, sacrificing image
     * quality to save memory.
     */
    public static final int MEMORY_POLICY_LOW_RAM = 0;

    
Use the most natural Config for the internal Bitmap. 
This is the recommended default for most applications and usages. This will use the closest Config for the encoded source. If the encoded source does not exactly match any Config, the next highest quality Config will be used avoiding any loss in image quality. /**
     * Use the most natural {@link Bitmap.Config} for the internal {@link Bitmap}.
     *
     * <p>This is the recommended default for most applications and usages. This
     * will use the closest {@link Bitmap.Config} for the encoded source. If the
     * encoded source does not exactly match any {@link Bitmap.Config}, the next
     * highest quality {@link Bitmap.Config} will be used avoiding any loss in
     * image quality.
     */
    public static final int MEMORY_POLICY_DEFAULT  = 1;

    
@hide
/** @hide **/
    @Retention(SOURCE)
    @IntDef(value = { MEMORY_POLICY_DEFAULT, MEMORY_POLICY_LOW_RAM },
              prefix = {"MEMORY_POLICY_"})
    public @interface MemoryPolicy {};

    
 Specify the memory policy for the decoded Bitmap. 
Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.
/**
     *  Specify the memory policy for the decoded {@link Bitmap}.
     *
     *  <p>Like all setters on ImageDecoder, this must be called inside
     *  {@link OnHeaderDecodedListener#onHeaderDecoded onHeaderDecoded}.</p>
     */
    public void setMemorySizePolicy(@MemoryPolicy int policy) {
        mConserveMemory = (policy == MEMORY_POLICY_LOW_RAM);
    }

    
 Retrieve the memory policy for the decoded Bitmap. /**
     *  Retrieve the memory policy for the decoded {@link Bitmap}.
     */
    @MemoryPolicy
    public int getMemorySizePolicy() {
        return mConserveMemory ? MEMORY_POLICY_LOW_RAM : MEMORY_POLICY_DEFAULT;
    }

    
@removed
Deprecated:
Replaced by setMemorySizePolicy./** @removed
     * @deprecated Replaced by {@link #setMemorySizePolicy}.
     */
    @Deprecated
    public void setConserveMemory(boolean conserveMemory) {
        mConserveMemory = conserveMemory;
    }

    
@removed
Deprecated:
Replaced by getMemorySizePolicy./** @removed
     * @deprecated Replaced by {@link #getMemorySizePolicy}.
     */
    @Deprecated
    public boolean getConserveMemory() {
        return mConserveMemory;
    }

    
 Specify whether to potentially treat the output as an alpha mask.
 
If this is set to true and the image is encoded in a format with only one channel, treat that channel as alpha. Otherwise this call has no effect.
 
This is incompatible with ALLOCATOR_HARDWARE. Trying to combine them will result in decodeDrawable/ decodeBitmap throwing an IllegalStateException.
 
Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.
/**
     *  Specify whether to potentially treat the output as an alpha mask.
     *
     *  <p>If this is set to {@code true} and the image is encoded in a format
     *  with only one channel, treat that channel as alpha. Otherwise this call has
     *  no effect.</p>
     *
     *  <p>This is incompatible with {@link #ALLOCATOR_HARDWARE}. Trying to
     *  combine them will result in {@link #decodeDrawable decodeDrawable}/
     *  {@link #decodeBitmap decodeBitmap} throwing an
     *  {@link java.lang.IllegalStateException}.</p>
     *
     *  <p>Like all setters on ImageDecoder, this must be called inside
     *  {@link OnHeaderDecodedListener#onHeaderDecoded onHeaderDecoded}.</p>
     */
    public void setDecodeAsAlphaMaskEnabled(boolean enabled) {
        mDecodeAsAlphaMask = enabled;
    }

    
@removed
Deprecated:
Renamed to setDecodeAsAlphaMaskEnabled./** @removed
     * @deprecated Renamed to {@link #setDecodeAsAlphaMaskEnabled}.
     */
    @Deprecated
    public ImageDecoder setDecodeAsAlphaMask(boolean enabled) {
        this.setDecodeAsAlphaMaskEnabled(enabled);
        return this;
    }

    
@removed
Deprecated:
Renamed to setDecodeAsAlphaMaskEnabled./** @removed
     * @deprecated Renamed to {@link #setDecodeAsAlphaMaskEnabled}.
     */
    @Deprecated
    public ImageDecoder setAsAlphaMask(boolean asAlphaMask) {
        this.setDecodeAsAlphaMask(asAlphaMask);
        return this;
    }

    
 Return whether to treat single channel input as alpha.
 
This returns whether setDecodeAsAlphaMaskEnabled was set to true. It may still return true even if the image has more than one channel and therefore will not be treated as an alpha mask.
/**
     *  Return whether to treat single channel input as alpha.
     *
     *  <p>This returns whether {@link #setDecodeAsAlphaMaskEnabled} was set to
     *  {@code true}. It may still return {@code true} even if the image has
     *  more than one channel and therefore will not be treated as an alpha
     *  mask.</p>
     */
    public boolean isDecodeAsAlphaMaskEnabled() {
        return mDecodeAsAlphaMask;
    }

    
@removed
Deprecated:
Renamed to isDecodeAsAlphaMaskEnabled./** @removed
     * @deprecated Renamed to {@link #isDecodeAsAlphaMaskEnabled}.
     */
    @Deprecated
    public boolean getDecodeAsAlphaMask() {
        return mDecodeAsAlphaMask;
    }

    
@removed
Deprecated:
Renamed to isDecodeAsAlphaMaskEnabled./** @removed
     * @deprecated Renamed to {@link #isDecodeAsAlphaMaskEnabled}.
     */
    @Deprecated
    public boolean getAsAlphaMask() {
        return this.getDecodeAsAlphaMask();
    }

    
Specify the desired ColorSpace for the output. 
If non-null, the decoder will try to decode into colorSpace. If it is null, which is the default, or the request cannot be met, the decoder will pick either the color space embedded in the image or the ColorSpace best suited for the requested image configuration (for instance sRGB for the Config.ARGB_8888 configuration).
Config.RGBA_F16 always uses the scRGB color space. Bitmaps in other configurations without an embedded color space are assumed to be in the sRGB color space.
Only Model.RGB color spaces are currently supported. An IllegalArgumentException will be thrown by decodeDrawable/ decodeBitmap when setting a non-RGB color space such as Lab.
The specified color space's transfer function must be an ICC parametric curve. An IllegalArgumentException will be thrown by the decode methods if calling Rgb.getTransferParameters() on the specified color space returns null.
Like all setters on ImageDecoder, this must be called inside onHeaderDecoded.
/**
     * Specify the desired {@link ColorSpace} for the output.
     *
     * <p>If non-null, the decoder will try to decode into {@code colorSpace}.
     * If it is null, which is the default, or the request cannot be met, the
     * decoder will pick either the color space embedded in the image or the
     * {@link ColorSpace} best suited for the requested image configuration
     * (for instance {@link ColorSpace.Named#SRGB sRGB} for the
     * {@link Bitmap.Config#ARGB_8888} configuration).</p>
     *
     * <p>{@link Bitmap.Config#RGBA_F16} always uses the
     * {@link ColorSpace.Named#LINEAR_EXTENDED_SRGB scRGB} color space.
     * Bitmaps in other configurations without an embedded color space are
     * assumed to be in the {@link ColorSpace.Named#SRGB sRGB} color space.</p>
     *
     * <p class="note">Only {@link ColorSpace.Model#RGB} color spaces are
     * currently supported. An <code>IllegalArgumentException</code> will
     * be thrown by {@link #decodeDrawable decodeDrawable}/
     * {@link #decodeBitmap decodeBitmap} when setting a non-RGB color space
     * such as {@link ColorSpace.Named#CIE_LAB Lab}.</p>
     *
     * <p class="note">The specified color space's transfer function must be
     * an {@link ColorSpace.Rgb.TransferParameters ICC parametric curve}. An
     * <code>IllegalArgumentException</code> will be thrown by the decode methods
     * if calling {@link ColorSpace.Rgb#getTransferParameters()} on the
     * specified color space returns null.</p>
     *
     * <p>Like all setters on ImageDecoder, this must be called inside
     * {@link OnHeaderDecodedListener#onHeaderDecoded onHeaderDecoded}.</p>
     */
    public void setTargetColorSpace(ColorSpace colorSpace) {
        mDesiredColorSpace = colorSpace;
    }

    
Closes this resource, relinquishing any underlying resources. This method
is invoked automatically on objects managed by the try-with-resources
statement.
This is an implementation detail of ImageDecoder, and should never be called manually.
/**
     * Closes this resource, relinquishing any underlying resources. This method
     * is invoked automatically on objects managed by the try-with-resources
     * statement.
     *
     * <p>This is an implementation detail of {@link ImageDecoder}, and should
     * never be called manually.</p>
     */
    @Override
    public void close() {
        mCloseGuard.close();
        if (!mClosed.compareAndSet(false, true)) {
            return;
        }
        nClose(mNativePtr);
        mNativePtr = 0;

        if (mOwnsInputStream) {
            IoUtils.closeQuietly(mInputStream);
        }
        IoUtils.closeQuietly(mAssetFd);

        mInputStream = null;
        mAssetFd = null;
        mTempStorage = null;
    }

    private void checkState() {
        if (mNativePtr == 0) {
            throw new IllegalStateException("Cannot use closed ImageDecoder!");
        }

        checkSubset(mDesiredWidth, mDesiredHeight, mCropRect);

        if (mAllocator == ALLOCATOR_HARDWARE) {
            if (mMutable) {
                throw new IllegalStateException("Cannot make mutable HARDWARE Bitmap!");
            }
            if (mDecodeAsAlphaMask) {
                throw new IllegalStateException("Cannot make HARDWARE Alpha mask Bitmap!");
            }
        }

        if (mPostProcessor != null && mUnpremultipliedRequired) {
            throw new IllegalStateException("Cannot draw to unpremultiplied pixels!");
        }

        if (mDesiredColorSpace != null) {
            if (!(mDesiredColorSpace instanceof ColorSpace.Rgb)) {
                throw new IllegalArgumentException("The target color space must use the "
                            + "RGB color model - provided: " + mDesiredColorSpace);
            }
            if (((ColorSpace.Rgb) mDesiredColorSpace).getTransferParameters() == null) {
                throw new IllegalArgumentException("The target color space must use an "
                            + "ICC parametric transfer function - provided: " + mDesiredColorSpace);
            }
        }
    }

    private static void checkSubset(int width, int height, Rect r) {
        if (r == null) {
            return;
        }
        if (r.left < 0 || r.top < 0 || r.right > width || r.bottom > height) {
            throw new IllegalStateException("Subset " + r + " not contained by "
                    + "scaled image bounds: (" + width + " x " + height + ")");
        }
    }

    @WorkerThread
    @NonNull
    private Bitmap decodeBitmapInternal() throws IOException {
        checkState();
        return nDecodeBitmap(mNativePtr, this, mPostProcessor != null,
                mDesiredWidth, mDesiredHeight, mCropRect,
                mMutable, mAllocator, mUnpremultipliedRequired,
                mConserveMemory, mDecodeAsAlphaMask, mDesiredColorSpace);
    }

    private void callHeaderDecoded(@Nullable OnHeaderDecodedListener listener,
            @NonNull Source src) {
        if (listener != null) {
            ImageInfo info = new ImageInfo(this);
            try {
                listener.onHeaderDecoded(this, info, src);
            } finally {
                info.mDecoder = null;
            }
        }
    }

    
 Create a Drawable from a Source. @param src representing the encoded image. @param listener for learning the ImageInfo and changing any default settings on the ImageDecoder. This will be called on the same thread as decodeDrawable before that method returns. This is required in order to change any of the default settings. @return Drawable for displaying the image. @throws IOException if src is not found, is an unsupported format, or cannot be decoded for any reason. /**
     *  Create a {@link Drawable} from a {@code Source}.
     *
     *  @param src representing the encoded image.
     *  @param listener for learning the {@link ImageInfo ImageInfo} and changing any
     *      default settings on the {@code ImageDecoder}. This will be called on
     *      the same thread as {@code decodeDrawable} before that method returns.
     *      This is required in order to change any of the default settings.
     *  @return Drawable for displaying the image.
     *  @throws IOException if {@code src} is not found, is an unsupported
     *      format, or cannot be decoded for any reason.
     */
    @WorkerThread
    @NonNull
    public static Drawable decodeDrawable(@NonNull Source src,
            @NonNull OnHeaderDecodedListener listener) throws IOException {
        if (listener == null) {
            throw new IllegalArgumentException("listener cannot be null! "
                    + "Use decodeDrawable(Source) to not have a listener");
        }
        return decodeDrawableImpl(src, listener);
    }

    @WorkerThread
    @NonNull
    private static Drawable decodeDrawableImpl(@NonNull Source src,
            @Nullable OnHeaderDecodedListener listener) throws IOException {
        try (ImageDecoder decoder = src.createImageDecoder()) {
            decoder.mSource = src;
            decoder.callHeaderDecoded(listener, src);

            if (decoder.mUnpremultipliedRequired) {
                // Though this could be supported (ignored) for opaque images,
                // it seems better to always report this error.
                throw new IllegalStateException("Cannot decode a Drawable " +
                                                "with unpremultiplied pixels!");
            }

            if (decoder.mMutable) {
                throw new IllegalStateException("Cannot decode a mutable " +
                                                "Drawable!");
            }

            // this call potentially manipulates the decoder so it must be performed prior to
            // decoding the bitmap and after decode set the density on the resulting bitmap
            final int srcDensity = decoder.computeDensity(src);
            if (decoder.mAnimated) {
                // AnimatedImageDrawable calls postProcessAndRelease only if
                // mPostProcessor exists.
                ImageDecoder postProcessPtr = decoder.mPostProcessor == null ?
                        null : decoder;
                Drawable d = new AnimatedImageDrawable(decoder.mNativePtr,
                        postProcessPtr, decoder.mDesiredWidth,
                        decoder.mDesiredHeight, srcDensity,
                        src.computeDstDensity(), decoder.mCropRect,
                        decoder.mInputStream, decoder.mAssetFd);
                // d has taken ownership of these objects.
                decoder.mInputStream = null;
                decoder.mAssetFd = null;
                return d;
            }

            Bitmap bm = decoder.decodeBitmapInternal();
            bm.setDensity(srcDensity);

            Resources res = src.getResources();
            byte[] np = bm.getNinePatchChunk();
            if (np != null && NinePatch.isNinePatchChunk(np)) {
                Rect opticalInsets = new Rect();
                bm.getOpticalInsets(opticalInsets);
                Rect padding = decoder.mOutPaddingRect;
                if (padding == null) {
                    padding = new Rect();
                }
                nGetPadding(decoder.mNativePtr, padding);
                return new NinePatchDrawable(res, bm, np, padding,
                        opticalInsets, null);
            }

            return new BitmapDrawable(res, bm);
        }
    }

    
 Create a Drawable from a Source. 
Since there is no OnHeaderDecodedListener, the default settings will be used. In order to change any settings, call decodeDrawable(Source, OnHeaderDecodedListener) instead.
 @param src representing the encoded image. @return Drawable for displaying the image. @throws IOException if src is not found, is an unsupported format, or cannot be decoded for any reason. /**
     *  Create a {@link Drawable} from a {@code Source}.
     *
     *  <p>Since there is no {@link OnHeaderDecodedListener OnHeaderDecodedListener},
     *  the default settings will be used. In order to change any settings, call
     *  {@link #decodeDrawable(Source, OnHeaderDecodedListener)} instead.</p>
     *
     *  @param src representing the encoded image.
     *  @return Drawable for displaying the image.
     *  @throws IOException if {@code src} is not found, is an unsupported
     *      format, or cannot be decoded for any reason.
     */
    @WorkerThread
    @NonNull
    public static Drawable decodeDrawable(@NonNull Source src)
            throws IOException {
        return decodeDrawableImpl(src, null);
    }

    
 Create a Bitmap from a Source. @param src representing the encoded image. @param listener for learning the ImageInfo and changing any default settings on the ImageDecoder. This will be called on the same thread as decodeBitmap before that method returns. This is required in order to change any of the default settings. @return Bitmap containing the image. @throws IOException if src is not found, is an unsupported format, or cannot be decoded for any reason. /**
     *  Create a {@link Bitmap} from a {@code Source}.
     *
     *  @param src representing the encoded image.
     *  @param listener for learning the {@link ImageInfo ImageInfo} and changing any
     *      default settings on the {@code ImageDecoder}. This will be called on
     *      the same thread as {@code decodeBitmap} before that method returns.
     *      This is required in order to change any of the default settings.
     *  @return Bitmap containing the image.
     *  @throws IOException if {@code src} is not found, is an unsupported
     *      format, or cannot be decoded for any reason.
     */
    @WorkerThread
    @NonNull
    public static Bitmap decodeBitmap(@NonNull Source src,
            @NonNull OnHeaderDecodedListener listener) throws IOException {
        if (listener == null) {
            throw new IllegalArgumentException("listener cannot be null! "
                    + "Use decodeBitmap(Source) to not have a listener");
        }
        return decodeBitmapImpl(src, listener);
    }

    @WorkerThread
    @NonNull
    private static Bitmap decodeBitmapImpl(@NonNull Source src,
            @Nullable OnHeaderDecodedListener listener) throws IOException {
        try (ImageDecoder decoder = src.createImageDecoder()) {
            decoder.mSource = src;
            decoder.callHeaderDecoded(listener, src);

            // this call potentially manipulates the decoder so it must be performed prior to
            // decoding the bitmap
            final int srcDensity = decoder.computeDensity(src);
            Bitmap bm = decoder.decodeBitmapInternal();
            bm.setDensity(srcDensity);

            Rect padding = decoder.mOutPaddingRect;
            if (padding != null) {
                byte[] np = bm.getNinePatchChunk();
                if (np != null && NinePatch.isNinePatchChunk(np)) {
                    nGetPadding(decoder.mNativePtr, padding);
                }
            }

            return bm;
        }
    }

    // This method may modify the decoder so it must be called prior to performing the decode
    private int computeDensity(@NonNull Source src) {
        // if the caller changed the size then we treat the density as unknown
        if (this.requestedResize()) {
            return Bitmap.DENSITY_NONE;
        }

        final int srcDensity = src.getDensity();
        if (srcDensity == Bitmap.DENSITY_NONE) {
            return srcDensity;
        }

        // Scaling up nine-patch divs is imprecise and is better handled
        // at draw time. An app won't be relying on the internal Bitmap's
        // size, so it is safe to let NinePatchDrawable handle scaling.
        // mPostProcessor disables nine-patching, so behave normally if
        // it is present.
        if (mIsNinePatch && mPostProcessor == null) {
            return srcDensity;
        }

        // Special stuff for compatibility mode: if the target density is not
        // the same as the display density, but the resource -is- the same as
        // the display density, then don't scale it down to the target density.
        // This allows us to load the system's density-correct resources into
        // an application in compatibility mode, without scaling those down
        // to the compatibility density only to have them scaled back up when
        // drawn to the screen.
        Resources res = src.getResources();
        if (res != null && res.getDisplayMetrics().noncompatDensityDpi == srcDensity) {
            return srcDensity;
        }

        final int dstDensity = src.computeDstDensity();
        if (srcDensity == dstDensity) {
            return srcDensity;
        }

        // For P and above, only resize if it would be a downscale. Scale up prior
        // to P in case the app relies on the Bitmap's size without considering density.
        if (srcDensity < dstDensity && sApiLevel >= Build.VERSION_CODES.P) {
            return srcDensity;
        }

        float scale = (float) dstDensity / srcDensity;
        int scaledWidth = (int) (mWidth * scale + 0.5f);
        int scaledHeight = (int) (mHeight * scale + 0.5f);
        this.setTargetSize(scaledWidth, scaledHeight);
        return dstDensity;
    }

    @NonNull
    private String getMimeType() {
        return nGetMimeType(mNativePtr);
    }

    @Nullable
    private ColorSpace getColorSpace() {
        return nGetColorSpace(mNativePtr);
    }

    
 Create a Bitmap from a Source. 
Since there is no OnHeaderDecodedListener, the default settings will be used. In order to change any settings, call decodeBitmap(Source, OnHeaderDecodedListener) instead.
 @param src representing the encoded image. @return Bitmap containing the image. @throws IOException if src is not found, is an unsupported format, or cannot be decoded for any reason. /**
     *  Create a {@link Bitmap} from a {@code Source}.
     *
     *  <p>Since there is no {@link OnHeaderDecodedListener OnHeaderDecodedListener},
     *  the default settings will be used. In order to change any settings, call
     *  {@link #decodeBitmap(Source, OnHeaderDecodedListener)} instead.</p>
     *
     *  @param src representing the encoded image.
     *  @return Bitmap containing the image.
     *  @throws IOException if {@code src} is not found, is an unsupported
     *      format, or cannot be decoded for any reason.
     */
    @WorkerThread
    @NonNull
    public static Bitmap decodeBitmap(@NonNull Source src) throws IOException {
        return decodeBitmapImpl(src, null);
    }

    
Private method called by JNI.
/**
     * Private method called by JNI.
     */
    @SuppressWarnings("unused")
    private int postProcessAndRelease(@NonNull Canvas canvas) {
        try {
            return mPostProcessor.onPostProcess(canvas);
        } finally {
            canvas.release();
        }
    }

    
Private method called by JNI.
/**
     * Private method called by JNI.
     */
    @SuppressWarnings("unused")
    private void onPartialImage(@DecodeException.Error int error, @Nullable Throwable cause)
            throws DecodeException {
        DecodeException exception = new DecodeException(error, cause, mSource);
        if (mOnPartialImageListener == null
                || !mOnPartialImageListener.onPartialImage(exception)) {
            throw exception;
        }
    }

    private static native ImageDecoder nCreate(long asset, Source src) throws IOException;
    private static native ImageDecoder nCreate(ByteBuffer buffer, int position,
                                               int limit, Source src) throws IOException;
    private static native ImageDecoder nCreate(byte[] data, int offset, int length,
                                               Source src) throws IOException;
    private static native ImageDecoder nCreate(InputStream is, byte[] storage,
                                               Source src) throws IOException;
    // The fd must be seekable.
    private static native ImageDecoder nCreate(FileDescriptor fd, Source src) throws IOException;
    @NonNull
    private static native Bitmap nDecodeBitmap(long nativePtr,
            @NonNull ImageDecoder decoder,
            boolean doPostProcess,
            int width, int height,
            @Nullable Rect cropRect, boolean mutable,
            int allocator, boolean unpremulRequired,
            boolean conserveMemory, boolean decodeAsAlphaMask,
            @Nullable ColorSpace desiredColorSpace)
        throws IOException;
    private static native Size nGetSampledSize(long nativePtr,
                                               int sampleSize);
    private static native void nGetPadding(long nativePtr, @NonNull Rect outRect);
    private static native void nClose(long nativePtr);
    private static native String nGetMimeType(long nativePtr);
    private static native ColorSpace nGetColorSpace(long nativePtr);
}