/*****************************************************************************
* Copyright (C) The Apache Software Foundation. All rights reserved. *
* ------------------------------------------------------------------------- *
* This software is published under the terms of the Apache Software License *
* version 1.1, a copy of which has been included with this distribution in *
* the LICENSE file. *
*****************************************************************************/
package org.apache.batik.transcoder.image;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferInt;
import java.awt.image.SinglePixelPackedSampleModel;
import java.io.IOException;
import java.io.OutputStream;
import org.apache.batik.transcoder.TranscoderException;
import org.apache.batik.transcoder.TranscoderOutput;
import org.apache.batik.transcoder.TranscodingHints;
import org.apache.batik.transcoder.image.resources.Messages;
import org.apache.batik.ext.awt.image.codec.PNGEncodeParam;
import org.apache.batik.ext.awt.image.codec.PNGImageEncoder;
/**
* This class is an <tt>ImageTranscoder</tt> that produces a PNG image.
*
* @author <a href="mailto:Thierry.Kormann@sophia.inria.fr">Thierry Kormann</a>
* @version $Id: PNGTranscoder.java,v 1.3 2001/01/23 17:12:46 tkormann Exp $
*/
public class PNGTranscoder extends ImageTranscoder {
/**
* Constructs a new transcoder that produces png images.
*/
public PNGTranscoder() { }
/**
* Creates a new ARGB image with the specified dimension.
* @param width the image width in pixels
* @param height the image height in pixels
*/
public BufferedImage createImage(int width, int height) {
return new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
}
/**
* Writes the specified image to the specified output.
* @param img the image to write
* @param output the output where to store the image
* @param TranscoderException if an error occured while storing the image
*/
public void writeImage(BufferedImage img, TranscoderOutput output)
throws TranscoderException {
OutputStream ostream = output.getOutputStream();
if (ostream == null) {
throw new TranscoderException(
Messages.formatMessage("png.badoutput", null));
}
PNGEncodeParam.RGB params =
(PNGEncodeParam.RGB)PNGEncodeParam.getDefaultEncodeParam(img);
params.setBackgroundRGB(new int [] { 255, 255, 255 });
//
// This is a trick so that viewers which do not support
// the alpha channel will see a white background (and not
// a black one).
//
int w = img.getWidth(), h = img.getHeight();
DataBufferInt biDB = (DataBufferInt)img.getRaster().getDataBuffer();
int scanStride = ((SinglePixelPackedSampleModel)img.getSampleModel()).getScanlineStride();
int dbOffset = biDB.getOffset();
int pixels[] = biDB.getBankData()[0];
int p = dbOffset;
int adjust = scanStride - w;
int a=0, r=0, g=0, b=0, pel=0;
for(int i=0; i<h; i++){
for(int j=0; j<w; j++){
pel = pixels[p];
a = (pel >> 24) & 0xff;
r = (pel >> 16) & 0xff;
g = (pel >> 8 ) & 0xff;
b = pel & 0xff;
r = (255*(255 -a) + a*r)/255;
g = (255*(255 -a) + a*g)/255;
b = (255*(255 -a) + a*b)/255;
pixels[p++] =
(a<<24 & 0xff000000) |
(r<<16 & 0xff0000) |
(g<<8 & 0xff00) |
(b & 0xff);
}
p += adjust;
}
try {
PNGImageEncoder pngEncoder = new PNGImageEncoder(ostream, params);
pngEncoder.encode(img);
} catch (IOException ex) {
throw new TranscoderException(ex);
}
}
}