ScanExpediterInterlaced.java
/*
* 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.
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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.ImagingException;
import org.apache.commons.imaging.formats.png.chunks.PngChunkPlte;
import org.apache.commons.imaging.formats.png.transparencyfilters.AbstractTransparencyFilter;
final class ScanExpediterInterlaced extends AbstractScanExpediter {
private static final int[] STARTING_ROW = { 0, 0, 4, 0, 2, 0, 1 };
private static final int[] STARTING_COL = { 0, 4, 0, 2, 0, 1, 0 };
private static final int[] ROW_INCREMENT = { 8, 8, 8, 4, 4, 2, 2 };
private static final int[] COL_INCREMENT = { 8, 8, 4, 4, 2, 2, 1 };
// private static final int[] Block_Height = { 8, 8, 4, 4, 2, 2, 1 };
// private static final int[] Block_Width = { 8, 4, 4, 2, 2, 1, 1 };
ScanExpediterInterlaced(final int width, final int height, final InputStream is, final BufferedImage bi, final PngColorType pngColorType,
final int bitDepth, final int bitsPerPixel, final PngChunkPlte pngChunkPLTE, final GammaCorrection gammaCorrection,
final AbstractTransparencyFilter abstractTransparencyFilter) {
super(width, height, is, bi, pngColorType, bitDepth, bitsPerPixel, pngChunkPLTE, gammaCorrection, abstractTransparencyFilter);
}
@Override
public void drive() throws ImagingException, IOException {
int pass = 1;
while (pass <= 7) {
byte[] prev = null;
int y = STARTING_ROW[pass - 1];
// int y_stride = ROW_INCREMENT[pass - 1];
// final boolean rows_in_pass = (y < height);
while (y < height) {
int x = STARTING_COL[pass - 1];
int pixelIndexInScanline = 0;
if (x < width) {
// only get data if there are pixels in this scanline/pass
final int columnsInRow = 1 + (width - STARTING_COL[pass - 1] - 1) / COL_INCREMENT[pass - 1];
final int bitsPerScanLine = bitsPerPixel * columnsInRow;
final int pixelBytesPerScanLine = getBitsToBytesRoundingUp(bitsPerScanLine);
final byte[] unfiltered = getNextScanline(is, pixelBytesPerScanLine, prev, bytesPerPixel);
prev = unfiltered;
final BitParser fBitParser = new BitParser(unfiltered, bitsPerPixel, bitDepth);
while (x < width) {
visit(x, y, bi, fBitParser, pixelIndexInScanline);
x += COL_INCREMENT[pass - 1];
pixelIndexInScanline++;
}
}
y += ROW_INCREMENT[pass - 1];
}
pass += 1;
}
}
private void visit(final int x, final int y, final BufferedImage bi, final BitParser fBitParser, final int pixelIndexInScanline)
throws ImagingException, IOException {
final int rgb = getRgb(fBitParser, pixelIndexInScanline);
bi.setRGB(x, y, rgb);
}
}