/*
* $RCSfile: PNGCodec.java,v $
*
* Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
*
* Use is subject to license terms.
*
* $Revision: 1.1 $
* $Date: 2005/02/11 04:55:37 $
* $State: Exp $
*/
package com.lightcrafts.media.jai.codecimpl;
import java.awt.image.ColorModel;
import java.awt.image.DataBuffer;
import java.awt.image.IndexColorModel;
import java.awt.image.RenderedImage;
import java.awt.image.SampleModel;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.IOException;
import java.io.OutputStream;
import com.lightcrafts.media.jai.codec.ImageCodec;
import com.lightcrafts.media.jai.codec.ImageDecoder;
import com.lightcrafts.media.jai.codec.ImageDecodeParam;
import com.lightcrafts.media.jai.codec.ImageEncoder;
import com.lightcrafts.media.jai.codec.ImageEncodeParam;
import com.lightcrafts.media.jai.codec.PNGDecodeParam;
import com.lightcrafts.media.jai.codec.PNGEncodeParam;
import com.lightcrafts.media.jai.codec.SeekableStream;
/**
* @since EA3
*/
public final class PNGCodec extends ImageCodec {
public PNGCodec() {}
public String getFormatName() {
return "png";
}
public Class getEncodeParamClass() {
return com.lightcrafts.media.jai.codec.PNGEncodeParam.class;
}
public Class getDecodeParamClass() {
return com.lightcrafts.media.jai.codec.PNGDecodeParam.class;
}
public boolean canEncodeImage(RenderedImage im,
ImageEncodeParam param) {
SampleModel sampleModel = im.getSampleModel();
// PNG doesn't handle float or double pixels
int dataType = sampleModel.getTransferType();
if ((dataType == DataBuffer.TYPE_FLOAT) ||
(dataType == DataBuffer.TYPE_DOUBLE)) {
return false;
}
int[] sampleSize = sampleModel.getSampleSize();
int bitDepth = sampleSize[0];
// Ensure all channels have the same bit depth
for (int i = 1; i < sampleSize.length; i++) {
if (sampleSize[i] != bitDepth) {
return false;
}
}
// Bit depth must be between 1 and 16
if (bitDepth < 1 || bitDepth > 16) {
return false;
}
// Number of bands must be between 1 and 4
int numBands = sampleModel.getNumBands();
if (numBands < 1 || numBands > 4) {
return false;
}
// Palette images must be 1-banded, depth 8 or less
ColorModel colorModel = im.getColorModel();
if (colorModel instanceof IndexColorModel) {
if (numBands != 1 || bitDepth > 8) {
return false;
}
}
// If a param object is supplied, check that it is of the right type
if (param != null) {
if (param instanceof PNGEncodeParam) {
if (colorModel instanceof IndexColorModel) {
if (!(param instanceof PNGEncodeParam.Palette) ) {
return false;
}
} else if (numBands < 3) {
if (!(param instanceof PNGEncodeParam.Gray) ) {
return false;
}
} else {
if (!(param instanceof PNGEncodeParam.RGB) ) {
return false;
}
}
} else {
return false;
}
}
return true;
}
protected ImageEncoder createImageEncoder(OutputStream dst,
ImageEncodeParam param) {
PNGEncodeParam p = null;
if (param != null) {
p = (PNGEncodeParam)param;
}
return new PNGImageEncoder(dst, p);
}
protected ImageDecoder createImageDecoder(InputStream src,
ImageDecodeParam param) {
PNGDecodeParam p = null;
if (param != null) {
p = (PNGDecodeParam)param;
}
return new PNGImageDecoder(src, p);
}
protected ImageDecoder createImageDecoder(File src,
ImageDecodeParam param)
throws IOException {
PNGDecodeParam p = null;
if (param != null) {
p = (PNGDecodeParam)param;
}
return new PNGImageDecoder(new FileInputStream(src), p);
}
protected ImageDecoder createImageDecoder(SeekableStream src,
ImageDecodeParam param) {
PNGDecodeParam p = null;
if (param != null) {
p = (PNGDecodeParam)param;
}
return new PNGImageDecoder(src, p);
}
public int getNumHeaderBytes() {
return 8;
}
public boolean isFormatRecognized(byte[] header) {
return ((header[0] == (byte)0x89) &&
(header[1] == (byte)0x50) &&
(header[2] == (byte)0x4e) &&
(header[3] == (byte)0x47) &&
(header[4] == (byte)0x0d) &&
(header[5] == (byte)0x0a) &&
(header[6] == (byte)0x1a) &&
(header[7] == (byte)0x0a));
}
}