/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */

/* $Id: FlateFilter.java 679326 2008-07-24 09:35:34Z vhennebert $ */

package org.apache.fop.pdf;

import java.io.IOException;
import java.io.OutputStream;

import org.apache.xmlgraphics.util.io.FlateEncodeOutputStream;

A filter to deflate a stream.

Note that the attributes for
prediction, colors, bitsPerComponent, and columns are not supported
when this filter is used to handle the data compression. They are
only valid for externally encoded data such as that from a graphics
file.
/**
 * A filter to deflate a stream.
 * <p>
 * <b>Note</b> that the attributes for
 * prediction, colors, bitsPerComponent, and columns are not supported
 * when this filter is used to handle the data compression. They are
 * only valid for externally encoded data such as that from a graphics
 * file.
 */
public class FlateFilter extends PDFFilter {
    
The supported mode when this filter is used for data compression
/**
     * The supported mode when this filter is used for data compression
     */
    public static final int PREDICTION_NONE = 1;

    
Mode for externally encoded data.
/**
     * Mode for externally encoded data.
     */
    public static final int PREDICTION_TIFF2 = 2;

    
Mode for externally encoded data.
/**
     * Mode for externally encoded data.
     */
    public static final int PREDICTION_PNG_NONE = 10;

    
Mode for externally encoded data.
/**
     * Mode for externally encoded data.
     */
    public static final int PREDICTION_PNG_SUB = 11;

    
Mode for externally encoded data.
/**
     * Mode for externally encoded data.
     */
    public static final int PREDICTION_PNG_UP = 12;

    
Mode for externally encoded data.
/**
     * Mode for externally encoded data.
     */
    public static final int PREDICTION_PNG_AVG = 13;

    
Mode for externally encoded data.
/**
     * Mode for externally encoded data.
     */
    public static final int PREDICTION_PNG_PAETH = 14;

    
Mode for externally encoded data.
/**
     * Mode for externally encoded data.
     */
    public static final int PREDICTION_PNG_OPT = 15;


    private int predictor = PREDICTION_NONE;
    private int colors;
    private int bitsPerComponent;
    private int columns;

    
Get the name of this filter.
Returns:
the pdf name of the flate decode filter/**
     * Get the name of this filter.
     *
     * @return the pdf name of the flate decode filter
     */
    public String getName() {
        return "/FlateDecode";
    }

    
Get the decode params for this filter.
Returns:
a string containing the decode params for this filter/**
     * Get the decode params for this filter.
     *
     * @return a string containing the decode params for this filter
     */
    public PDFObject getDecodeParms() {
        if (predictor > PREDICTION_NONE) {
            PDFDictionary dict = new PDFDictionary();
            dict.put("Predictor", predictor);
            if (colors > 1) {
                dict.put("Colors", colors);
            }
            if (bitsPerComponent > 0 && bitsPerComponent != 8) {
                dict.put("BitsPerComponent", bitsPerComponent);
            }
            if (columns > 1) {
                dict.put("Columns", columns);
            }
            return dict;
        }
        return null;
    }

    
Set the predictor for this filter.
Params:
predictor – the predictor to use
Throws:
PDFFilterException – if there is an error with the predictor/**
     * Set the predictor for this filter.
     *
     * @param predictor the predictor to use
     * @throws PDFFilterException if there is an error with the predictor
     */
    public void setPredictor(int predictor) throws PDFFilterException {
        this.predictor = predictor;

    }

    
Get the predictor for this filter.
Returns:
the predictor used for this filter/**
     * Get the predictor for this filter.
     *
     * @return the predictor used for this filter
     */
    public int getPredictor() {
        return predictor;
    }

    
Set the colors for this filter.
Params:
colors – the colors to use
Throws:
PDFFilterException – if predictor is not PREDICTION_NONE/**
     * Set the colors for this filter.
     *
     * @param colors the colors to use
     * @throws PDFFilterException if predictor is not PREDICTION_NONE
     */
    public void setColors(int colors) throws PDFFilterException {
        if (predictor != PREDICTION_NONE) {
            this.colors = colors;
        } else {
            throw new PDFFilterException(
                          "Prediction must not be PREDICTION_NONE in"
                          + " order to set Colors");
        }
    }

    
Get the colors for this filter.
Returns:
the colors for this filter/**
     * Get the colors for this filter.
     *
     * @return the colors for this filter
     */
    public int getColors() {
        return colors;
    }

    
Set the number of bits per component.
Params:
bits – the number of bits per component
Throws:
PDFFilterException – if predictor is not PREDICTION_NONE/**
     * Set the number of bits per component.
     *
     * @param bits the number of bits per component
     * @throws PDFFilterException if predictor is not PREDICTION_NONE
     */
    public void setBitsPerComponent(int bits) throws PDFFilterException {
        if (predictor != PREDICTION_NONE) {
            bitsPerComponent = bits;
        } else {
            throw new PDFFilterException(
                         "Prediction must not be PREDICTION_NONE in order"
                         + " to set bitsPerComponent");
        }
    }

    
Get the number of bits per component.
Returns:
the number of bits per component/**
     * Get the number of bits per component.
     *
     * @return the number of bits per component
     */
    public int getBitsPerComponent() {
        return bitsPerComponent;
    }

    
Set the number of columns for this filter.
Params:
columns – the number of columns to use for the filter
Throws:
PDFFilterException – if predictor is not PREDICTION_NONE/**
     * Set the number of columns for this filter.
     *
     * @param columns the number of columns to use for the filter
     * @throws PDFFilterException if predictor is not PREDICTION_NONE
     */
    public void setColumns(int columns) throws PDFFilterException {
        if (predictor != PREDICTION_NONE) {
            this.columns = columns;
        } else {
            throw new PDFFilterException(
                      "Prediction must not be PREDICTION_NONE in"
                      + " order to set Columns");
        }
    }

    
Get the number of columns for this filter.
Returns:
the number of columns/**
     * Get the number of columns for this filter.
     *
     * @return the number of columns
     */
    public int getColumns() {
        return columns;
    }


    
{@inheritDoc} /** {@inheritDoc} */
    public OutputStream applyFilter(OutputStream out) throws IOException {
        if (isApplied()) {
            return out;
        } else {
            return new FlateEncodeOutputStream(out);
        }
    }

}