/*
* 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.
*/
package org.apache.shindig.gadgets.rewrite.image;
import org.apache.sanselan.ImageReadException;
import org.apache.sanselan.Sanselan;
import org.apache.shindig.gadgets.http.HttpResponse;
import javax.imageio.ImageIO;
import javax.imageio.ImageWriteParam;
import javax.imageio.ImageWriter;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.io.IOException;
import java.io.InputStream;
/**
* Optimize a PNG image and possibly convert it to a JPEG.
*/
class PNGOptimizer extends BaseOptimizer {
public static BufferedImage readPng(InputStream is)
throws ImageReadException, IOException {
return Sanselan.getBufferedImage(is);
}
private boolean useJpeg;
public PNGOptimizer(OptimizerConfig config, HttpResponse original) {
super(config, original);
}
@Override
protected void rewriteImpl(BufferedImage bufferedImage) throws IOException {
BufferedImage palettized = ImageUtils.palettize(bufferedImage, config.getMaxPaletteSize());
if (palettized != null) {
write(palettized);
}
if (palettized == null) {
// If we are efficiently palletized then only JPEG can really win
if (this.minBytes == null) {
// nothing has been written yet, so just strip metadata
write(bufferedImage);
}
// Depalettized images can win when a large palette has unused entries
BufferedImage depalettized = ImageUtils.depalettize(bufferedImage,
config.getMaxInMemoryBytes());
if (depalettized != null) {
write(depalettized);
}
}
// Try JPEG for truly opaque images
if (config.isJpegConversionAllowed()) {
boolean isOpaque;
if (palettized != null){
bufferedImage = palettized;
isOpaque = bufferedImage.getColorModel().getTransparency() == ColorModel.OPAQUE;
} else {
isOpaque = ImageUtils.isOpaque(bufferedImage);
}
if (isOpaque) {
byte[] lastBytes = minBytes;
int prevReductionPct = reductionPct;
// Workaround for bug in JPEG image writer
// http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6444933
// Writer seems to think color space is CMYK and not RGBA. In this
// case the image is fully opaque so we can just down-convert to just RGB.
BufferedImage rgbOnlyImage = new BufferedImage(bufferedImage.getWidth(),
bufferedImage.getHeight(),
BufferedImage.TYPE_INT_RGB);
rgbOnlyImage.getGraphics().drawImage(bufferedImage, 0, 0, null);
ImageWriter writer = ImageIO.getImageWritersByFormatName("jpeg").next();
ImageWriteParam param = writer.getDefaultWriteParam();
param.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
param.setCompressionQuality(config.getJpegCompression());
outputter = new ImageIOOutputter(writer, param);
write(rgbOnlyImage);
// Only use JPEG if it offers a significant reduction over other methods
if (reductionPct > prevReductionPct + 20) {
useJpeg = true;
} else {
minBytes = lastBytes;
}
}
}
}
@Override
protected String getOutputContentType() {
if (useJpeg) {
return "image/jpeg";
}
return "image/png";
}
@Override
protected String getOriginalContentType() {
return "image/png";
}
@Override
protected String getOriginalFormatName() {
return "png";
}
}