PixelParserRgb.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.
*/
package org.apache.commons.imaging.formats.bmp;
import static org.apache.commons.imaging.common.BinaryFunctions.read2Bytes;
import static org.apache.commons.imaging.common.BinaryFunctions.readByte;
import java.io.IOException;
import java.nio.ByteOrder;
import org.apache.commons.imaging.ImagingException;
final class PixelParserRgb extends AbstractPixelParserSimple {
private int byteCount;
private int cachedBitCount;
private int cachedByte;
PixelParserRgb(final BmpHeaderInfo bhi, final byte[] colorTable, final byte[] imageData) {
super(bhi, colorTable, imageData);
}
@Override
public int getNextRgb() throws ImagingException, IOException {
switch (bhi.bitsPerPixel) {
case 1:
case 4: {
if (cachedBitCount < bhi.bitsPerPixel) {
if (cachedBitCount != 0) {
throw new ImagingException("Unexpected leftover bits: " + cachedBitCount + "/" + bhi.bitsPerPixel);
}
cachedBitCount += 8;
cachedByte = 0xff & imageData[byteCount];
byteCount++;
}
final int cacheMask = (1 << bhi.bitsPerPixel) - 1;
final int sample = cacheMask & cachedByte >> 8 - bhi.bitsPerPixel;
cachedByte = 0xff & cachedByte << bhi.bitsPerPixel;
cachedBitCount -= bhi.bitsPerPixel;
return getColorTableRgb(sample);
}
case 8: {
final int sample = 0xff & imageData[byteCount + 0];
final int rgb = getColorTableRgb(sample);
byteCount += 1;
return rgb;
}
case 16: {
final int data = read2Bytes("Pixel", is, "BMP Image Data", ByteOrder.LITTLE_ENDIAN);
final int blue = (0x1f & data >> 0) << 3;
final int green = (0x1f & data >> 5) << 3;
final int red = (0x1f & data >> 10) << 3;
final int alpha = 0xff;
final int rgb = alpha << 24 | red << 16 | green << 8 | blue << 0;
byteCount += 2;
return rgb;
}
case 24: {
final int blue = 0xff & imageData[byteCount + 0];
final int green = 0xff & imageData[byteCount + 1];
final int red = 0xff & imageData[byteCount + 2];
final int alpha = 0xff;
final int rgb = alpha << 24 | red << 16 | green << 8 | blue << 0;
byteCount += 3;
return rgb;
}
case 32: {
final int blue = 0xff & imageData[byteCount + 0];
final int green = 0xff & imageData[byteCount + 1];
final int red = 0xff & imageData[byteCount + 2];
final int alpha = 0xff;
final int rgb = alpha << 24 | red << 16 | green << 8 | blue << 0;
byteCount += 4;
return rgb;
}
default:
break;
}
throw new ImagingException("Unknown BitsPerPixel: " + bhi.bitsPerPixel);
}
@Override
public void newline() throws ImagingException, IOException {
cachedBitCount = 0;
while (byteCount % 4 != 0) {
readByte("Pixel", is, "BMP Image Data");
byteCount++;
}
}
}