/*
* 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.commons.imaging.formats.png;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.InputStream;
import org.apache.commons.imaging.ImageReadException;
import org.apache.commons.imaging.formats.png.chunks.PngChunkPlte;
import org.apache.commons.imaging.formats.png.scanlinefilters.ScanlineFilter;
import org.apache.commons.imaging.formats.png.scanlinefilters.ScanlineFilterAverage;
import org.apache.commons.imaging.formats.png.scanlinefilters.ScanlineFilterNone;
import org.apache.commons.imaging.formats.png.scanlinefilters.ScanlineFilterPaeth;
import org.apache.commons.imaging.formats.png.scanlinefilters.ScanlineFilterSub;
import org.apache.commons.imaging.formats.png.scanlinefilters.ScanlineFilterUp;
import org.apache.commons.imaging.formats.png.transparencyfilters.TransparencyFilter;
import static org.apache.commons.imaging.common.BinaryFunctions.*;
abstract class ScanExpediter {
protected final int width;
protected final int height;
protected final InputStream is;
protected final BufferedImage bi;
protected final ColorType colorType;
protected final int bitDepth;
protected final int bytesPerPixel;
protected final int bitsPerPixel;
protected final PngChunkPlte pngChunkPLTE;
protected final GammaCorrection gammaCorrection;
protected final TransparencyFilter transparencyFilter;
public ScanExpediter(final int width, final int height, final InputStream is,
final BufferedImage bi, final ColorType colorType, final int bitDepth, final int bitsPerPixel,
final PngChunkPlte pngChunkPLTE, final GammaCorrection gammaCorrection,
final TransparencyFilter transparencyFilter)
{
this.width = width;
this.height = height;
this.is = is;
this.bi = bi;
this.colorType = colorType;
this.bitDepth = bitDepth;
this.bytesPerPixel = this.getBitsToBytesRoundingUp(bitsPerPixel);
this.bitsPerPixel = bitsPerPixel;
this.pngChunkPLTE = pngChunkPLTE;
this.gammaCorrection = gammaCorrection;
this.transparencyFilter = transparencyFilter;
}
protected final int getBitsToBytesRoundingUp(final int bits) {
return (bits + 7) / 8;
}
protected final int getPixelARGB(final int alpha, final int red, final int green, final int blue) {
return ((0xff & alpha) << 24)
| ((0xff & red) << 16)
| ((0xff & green) << 8)
| ((0xff & blue) << 0);
}
protected final int getPixelRGB(final int red, final int green, final int blue) {
return getPixelARGB(0xff, red, green, blue);
}
public abstract void drive() throws ImageReadException, IOException;
protected int getRGB(final BitParser bitParser, final int pixelIndexInScanline)
throws ImageReadException, IOException {
switch (colorType) {
case GREYSCALE: {
// 1,2,4,8,16 Each pixel is a grayscale sample.
int sample = bitParser.getSampleAsByte(pixelIndexInScanline, 0);
if (gammaCorrection != null) {
sample = gammaCorrection.correctSample(sample);
}
int rgb = getPixelRGB(sample, sample, sample);
if (transparencyFilter != null) {
rgb = transparencyFilter.filter(rgb, sample);
}
return rgb;
}
case TRUE_COLOR: {
// 8,16 Each pixel is an R,G,B triple.
int red = bitParser.getSampleAsByte(pixelIndexInScanline, 0);
int green = bitParser.getSampleAsByte(pixelIndexInScanline, 1);
int blue = bitParser.getSampleAsByte(pixelIndexInScanline, 2);
int rgb = getPixelRGB(red, green, blue);
if (transparencyFilter != null) {
rgb = transparencyFilter.filter(rgb, -1);
}
if (gammaCorrection != null) {
final int alpha = (0xff000000 & rgb) >> 24; // make sure to preserve
// transparency
red = gammaCorrection.correctSample(red);
green = gammaCorrection.correctSample(green);
blue = gammaCorrection.correctSample(blue);
rgb = getPixelARGB(alpha, red, green, blue);
}
return rgb;
}
//
case INDEXED_COLOR: {
// 1,2,4,8 Each pixel is a palette index;
// a PLTE chunk must appear.
final int index = bitParser.getSample(pixelIndexInScanline, 0);
int rgb = pngChunkPLTE.getRGB(index);
if (transparencyFilter != null) {
rgb = transparencyFilter.filter(rgb, index);
}
return rgb;
}
case GREYSCALE_WITH_ALPHA: {
// 8,16 Each pixel is a grayscale sample,
// followed by an alpha sample.
int sample = bitParser.getSampleAsByte(pixelIndexInScanline, 0);
final int alpha = bitParser.getSampleAsByte(pixelIndexInScanline, 1);
if (gammaCorrection != null) {
sample = gammaCorrection.correctSample(sample);
}
return getPixelARGB(alpha, sample, sample, sample);
}
case TRUE_COLOR_WITH_ALPHA: {
// 8,16 Each pixel is an R,G,B triple,
int red = bitParser.getSampleAsByte(pixelIndexInScanline, 0);
int green = bitParser.getSampleAsByte(pixelIndexInScanline, 1);
int blue = bitParser.getSampleAsByte(pixelIndexInScanline, 2);
final int alpha = bitParser.getSampleAsByte(pixelIndexInScanline, 3);
if (gammaCorrection != null) {
red = gammaCorrection.correctSample(red);
green = gammaCorrection.correctSample(green);
blue = gammaCorrection.correctSample(blue);
}
return getPixelARGB(alpha, red, green, blue);
}
default:
throw new ImageReadException("PNG: unknown color type: " + colorType);
}
}
protected ScanlineFilter getScanlineFilter(FilterType filterType, int bytesPerPixel) throws ImageReadException {
switch (filterType) {
case NONE:
return new ScanlineFilterNone();
case SUB:
return new ScanlineFilterSub(bytesPerPixel);
case UP:
return new ScanlineFilterUp();
case AVERAGE:
return new ScanlineFilterAverage(bytesPerPixel);
case PAETH:
return new ScanlineFilterPaeth(bytesPerPixel);
}
return null;
}
protected byte[] unfilterScanline(final FilterType filterType, final byte[] src, final byte[] prev,
final int bytesPerPixel) throws ImageReadException, IOException {
final ScanlineFilter filter = getScanlineFilter(filterType, bytesPerPixel);
final byte[] dst = new byte[src.length];
filter.unfilter(src, dst, prev);
return dst;
}
protected byte[] getNextScanline(final InputStream is, final int length, final byte[] prev,
final int bytesPerPixel) throws ImageReadException, IOException {
final int filterType = is.read();
if (filterType < 0) {
throw new ImageReadException("PNG: missing filter type");
}
if (filterType >= FilterType.values().length) {
throw new ImageReadException("PNG: unknown filterType: " + filterType);
}
byte[] scanline = readBytes("scanline", is, length, "PNG: missing image data");
return unfilterScanline(FilterType.values()[filterType], scanline, prev, bytesPerPixel);
}
}