/*
* 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.sanselan.formats.bmp.pixelparsers;
import java.io.IOException;
import org.apache.sanselan.ImageReadException;
import org.apache.sanselan.formats.bmp.BmpHeaderInfo;
public class PixelParserBitFields extends PixelParserSimple
{
private final int redShift;
private final int greenShift;
private final int blueShift;
private final int alphaShift;
private final int redMask;
private final int greenMask;
private final int blueMask;
private final int alphaMask;
public PixelParserBitFields(BmpHeaderInfo bhi, byte ColorTable[],
byte ImageData[]) throws ImageReadException, IOException
{
super(bhi, ColorTable, ImageData);
redMask = bhi.redMask;
greenMask = bhi.greenMask;
blueMask = bhi.blueMask;
alphaMask = bhi.alphaMask;
redShift = getMaskShift(redMask);
greenShift = getMaskShift(greenMask);
blueShift = getMaskShift(blueMask);
alphaShift = (alphaMask != 0 ? getMaskShift(alphaMask) : 0);
}
private int getMaskShift(int mask)
{
int trailingZeroes = 0;
while ((0x1 & mask) == 0)
{
mask = 0x7fffffff & (mask >> 1);
trailingZeroes++;
}
int maskLength = 0;
while ((0x1 & mask) == 1)
{
mask = 0x7fffffff & (mask >> 1);
maskLength++;
}
return (trailingZeroes - (8 - maskLength));
}
private int bytecount = 0;
public int getNextRGB() throws ImageReadException, IOException
{
int data;
if (bhi.bitsPerPixel == 8)
{
data = 0xff & imageData[bytecount + 0];
bytecount += 1;
}
else if (bhi.bitsPerPixel == 24)
{
data = bfp.read3Bytes("Pixel", is, "BMP Image Data");
bytecount += 3;
}
else if (bhi.bitsPerPixel == 32)
{
data = bfp.read4Bytes("Pixel", is, "BMP Image Data");
bytecount += 4;
}
else if (bhi.bitsPerPixel == 16)
{
data = bfp.read2Bytes("Pixel", is, "BMP Image Data");
bytecount += 2;
}
else
throw new ImageReadException("Unknown BitsPerPixel: "
+ bhi.bitsPerPixel);
int red = (redMask & data);
int green = (greenMask & data);
int blue = (blueMask & data);
int alpha = (alphaMask != 0 ? alphaMask & data : 0xff);
red = (redShift >= 0) ? red >> redShift : red << -redShift;
green = (greenShift >= 0) ? green >> greenShift : green << -greenShift;
blue = (blueShift >= 0) ? blue >> blueShift : blue << -blueShift;
alpha = (alphaShift >= 0) ? alpha >> alphaShift : alpha << -alphaShift;
int rgb = (alpha << 24) | (red << 16) | (green << 8) | (blue << 0);
return rgb;
}
public void newline() throws ImageReadException, IOException
{
while (((bytecount) % 4) != 0)
{
bfp.readByte("Pixel", is, "BMP Image Data");
bytecount++;
}
}
}