/*
* 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.
* <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
*/
public static final int PREDICTION_NONE = 1;
/**
* Mode for externally encoded data.
*/
public static final int PREDICTION_TIFF2 = 2;
/**
* Mode for externally encoded data.
*/
public static final int PREDICTION_PNG_NONE = 10;
/**
* Mode for externally encoded data.
*/
public static final int PREDICTION_PNG_SUB = 11;
/**
* Mode for externally encoded data.
*/
public static final int PREDICTION_PNG_UP = 12;
/**
* Mode for externally encoded data.
*/
public static final int PREDICTION_PNG_AVG = 13;
/**
* Mode for externally encoded data.
*/
public static final int PREDICTION_PNG_PAETH = 14;
/**
* 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.
*
* @return the pdf name of the flate decode filter
*/
public String getName() {
return "/FlateDecode";
}
/**
* 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.
*
* @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.
*
* @return the predictor used for this filter
*/
public int getPredictor() {
return predictor;
}
/**
* 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.
*
* @return the colors for this filter
*/
public int getColors() {
return colors;
}
/**
* 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.
*
* @return the number of bits per component
*/
public int getBitsPerComponent() {
return bitsPerComponent;
}
/**
* 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.
*
* @return the number of columns
*/
public int getColumns() {
return columns;
}
/** {@inheritDoc} */
public OutputStream applyFilter(OutputStream out) throws IOException {
if (isApplied()) {
return out;
} else {
return new FlateEncodeOutputStream(out);
}
}
}