| /* BMPDecoder.java -- |
| Copyright (C) 2005 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| package gnu.javax.imageio.bmp; |
| |
| import java.io.IOException; |
| import javax.imageio.stream.ImageInputStream; |
| import java.nio.ByteBuffer; |
| import java.nio.ByteOrder; |
| import java.awt.image.IndexColorModel; |
| import java.awt.image.BufferedImage; |
| |
| public abstract class BMPDecoder { |
| |
| protected BMPInfoHeader infoHeader; |
| protected BMPFileHeader fileHeader; |
| protected long offset; |
| |
| public BMPDecoder(BMPFileHeader fh, BMPInfoHeader ih){ |
| fileHeader = fh; |
| infoHeader = ih; |
| offset = BMPFileHeader.SIZE + BMPInfoHeader.SIZE; |
| } |
| |
| /** |
| * Determines the coding type of the bitmap and returns the corresponding |
| * decoder. |
| */ |
| public static BMPDecoder getDecoder(BMPFileHeader fh, BMPInfoHeader ih){ |
| switch(ih.getCompression()){ |
| case BMPInfoHeader.BI_RGB: // uncompressed RGB |
| switch(ih.getBitCount()){ |
| case 32: |
| return new DecodeBF32(fh, ih, true); |
| |
| case 24: |
| return new DecodeRGB24(fh, ih); |
| |
| case 16: |
| return new DecodeBF16(fh, ih, true); |
| |
| case 8: |
| return new DecodeRGB8(fh, ih); |
| |
| case 4: |
| return new DecodeRGB4(fh, ih); |
| |
| case 1: |
| return new DecodeRGB1(fh, ih); |
| |
| default: |
| return null; |
| } |
| |
| case BMPInfoHeader.BI_RLE8: |
| return new DecodeRLE8(fh, ih); |
| |
| case BMPInfoHeader.BI_RLE4: |
| return new DecodeRLE4(fh, ih); |
| |
| case BMPInfoHeader.BI_BITFIELDS: |
| switch(ih.getBitCount()){ |
| case 16: |
| return new DecodeBF16(fh, ih, false); |
| |
| case 32: |
| return new DecodeBF32(fh, ih, false); |
| |
| default: |
| return null; |
| } |
| |
| default: |
| return null; |
| } |
| } |
| |
| /** |
| * The image decoder. |
| */ |
| public abstract BufferedImage decode(ImageInputStream in) |
| throws IOException, BMPException; |
| |
| /** |
| * Reads r,g,b bit masks from an inputstream |
| */ |
| protected int[] readBitMasks(ImageInputStream in) throws IOException { |
| int[] bitmasks = new int[3]; |
| byte[] temp = new byte[12]; |
| if(in.read(temp) != 12) |
| throw new IOException("Couldn't read bit masks."); |
| offset += 12; |
| |
| ByteBuffer buf = ByteBuffer.wrap(temp); |
| buf.order(ByteOrder.LITTLE_ENDIAN); |
| bitmasks[0] = buf.getInt(); |
| bitmasks[1] = buf.getInt(); |
| bitmasks[2] = buf.getInt(); |
| return bitmasks; |
| } |
| |
| /** |
| * Reads an N-color palette from an inputstream in RGBQUAD format and |
| * returns an equivalent ColorModel object |
| */ |
| protected IndexColorModel readPalette(ImageInputStream in) throws IOException { |
| int N = infoHeader.getNumberOfPaletteEntries(); |
| byte[] r = new byte[N]; |
| byte[] g = new byte[N]; |
| byte[] b = new byte[N]; |
| for(int i=0;i<N;i++){ |
| byte[] RGBquad = new byte[4]; |
| if(in.read(RGBquad) != 4) |
| throw new IOException("Error reading palette information."); |
| // RGBQUAD structure is b,g,r,0 |
| r[i] = RGBquad[2]; |
| g[i] = RGBquad[1]; |
| b[i] = RGBquad[0]; |
| } |
| |
| offset += 4*N; |
| return new IndexColorModel(8, N, r, g, b); |
| } |
| |
| /** |
| * Read bytes to the start of the image data |
| */ |
| protected void skipToImage(ImageInputStream in) throws IOException { |
| byte[] d = new byte[1]; |
| long n = fileHeader.getOffset() - offset; |
| for(int i=0;i<n;i++) |
| in.read(d); |
| } |
| } |