jpegfileformat.java

源码为Eclipse开源开发平台桌面开发工具SWT的源代码,

/*******************************************************************************
 * Copyright (c) 2000, 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.internal.image;


import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import java.io.*;

final class JPEGFileFormat extends FileFormat {
	int restartInterval;
	JPEGFrameHeader frameHeader;
	int imageWidth, imageHeight;
	int interleavedMcuCols, interleavedMcuRows;
	int maxV, maxH;
	boolean progressive;
	int samplePrecision;
	int nComponents;
	int[][] frameComponents;
	int[] componentIds;
	byte[][] imageComponents;
	int[] dataUnit;
	int[][][] dataUnits;
	int[] precedingDCs;
	JPEGScanHeader scanHeader;
	byte[] dataBuffer;
	int currentBitCount;
	int bufferCurrentPosition;
	int restartsToGo;
	int nextRestartNumber;
	JPEGArithmeticConditioningTable arithmeticTables;
	JPEGHuffmanTable[] acHuffmanTables;
	JPEGHuffmanTable[] dcHuffmanTables;
	int[][] quantizationTables;
	int currentByte;
	int decoderQFactor;
	int encoderQFactor = 75;
	int eobrun = 0;
	/* JPEGConstants */
	public static final int DCTSIZE = 8;
	public static final int DCTSIZESQR = 64;
	/* JPEGFixedPointConstants */
	public static final int FIX_0_899976223 = 7373;
	public static final int FIX_1_961570560 = 16069;
	public static final int FIX_2_053119869 = 16819;
	public static final int FIX_0_298631336 = 2446;
	public static final int FIX_1_847759065 = 15137;
	public static final int FIX_1_175875602 = 9633;
	public static final int FIX_3_072711026 = 25172;
	public static final int FIX_0_765366865 = 6270;
	public static final int FIX_2_562915447 = 20995;
	public static final int FIX_0_541196100 = 4433;
	public static final int FIX_0_390180644 = 3196;
	public static final int FIX_1_501321110 = 12299;
	/* JPEGMarkerCodes */
	public static final int APP0  = 0xFFE0;
	public static final int APP15 = 0xFFEF;
	public static final int COM   = 0xFFFE;
	public static final int DAC   = 0xFFCC;
	public static final int DHP   = 0xFFDE;
	public static final int DHT   = 0xFFC4;
	public static final int DNL   = 0xFFDC;
	public static final int DRI   = 0xFFDD;
	public static final int DQT   = 0xFFDB;
	public static final int EOI   = 0xFFD9;
	public static final int EXP   = 0xFFDF;
	public static final int JPG   = 0xFFC8;
	public static final int JPG0  = 0xFFF0;
	public static final int JPG13 = 0xFFFD;
	public static final int RST0  = 0xFFD0;
	public static final int RST1  = 0xFFD1;
	public static final int RST2  = 0xFFD2;
	public static final int RST3  = 0xFFD3;
	public static final int RST4  = 0xFFD4;
	public static final int RST5  = 0xFFD5;
	public static final int RST6  = 0xFFD6;
	public static final int RST7  = 0xFFD7;
	public static final int SOF0  = 0xFFC0;
	public static final int SOF1  = 0xFFC1;
	public static final int SOF2  = 0xFFC2;
	public static final int SOF3  = 0xFFC3;
	public static final int SOF5  = 0xFFC5;
	public static final int SOF6  = 0xFFC6;
	public static final int SOF7  = 0xFFC7;
	public static final int SOF9  = 0xFFC9;
	public static final int SOF10 = 0xFFCA;
	public static final int SOF11 = 0xFFCB;
	public static final int SOF13 = 0xFFCD;
	public static final int SOF14 = 0xFFCE;
	public static final int SOF15 = 0xFFCF;
	public static final int SOI   = 0xFFD8;
	public static final int SOS   = 0xFFDA;
	public static final int TEM   = 0xFF01;
	/* JPEGFrameComponentParameterConstants */
	public static final int TQI	= 0;
	public static final int HI	= 1;
	public static final int VI	= 2;
	public static final int CW	= 3;
	public static final int CH	= 4;
	/* JPEGScanComponentParameterConstants */
	public static final int DC	= 0;
	public static final int AC	= 1;
	/* JFIF Component Constants */
	public static final int ID_Y		= 1 - 1;
	public static final int ID_CB	= 2 - 1;
	public static final int ID_CR	= 3 - 1;

	public static final int[] ExtendTest = {
		0, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 
		4096, 8192, 16384, 32768, 65536, 131072, 262144
	};
	public static final int[] ExtendOffset = new int[] {
		0, -1, -3, -7, -15, -31, -63, -127, -255, -511, -1023, -2047, 
		-4095, -8191, -16383, -32767, -65535, -131071, -262143
	};
	public static final int[] ZigZag8x8 = {
		0, 1, 8, 16, 9, 2, 3, 10,
		17, 24, 32, 25, 18, 11, 4, 5,
		12, 19, 26, 33, 40, 48, 41, 34,
		27, 20, 13, 6, 7, 14, 21, 28,
		35, 42, 49, 56, 57, 50, 43, 36,
		29, 22, 15, 23, 30, 37, 44, 51,
		58, 59, 52, 45, 38, 31, 39, 46,
		53, 60, 61, 54, 47, 55, 62, 63
	};
	public static int[] CrRTable, CbBTable, CrGTable, CbGTable;
	public static int[] RYTable, GYTable, BYTable,
		RCbTable, GCbTable, BCbTable, RCrTable, GCrTable, BCrTable, NBitsTable;
	static {
		initialize();
	}
void compress(ImageData image, byte[] dataYComp, byte[] dataCbComp, byte[] dataCrComp) {
	int srcWidth = image.width;
	int srcHeight = image.height;
	int vhFactor = maxV * maxH;
	int[] frameComponent;
	imageComponents = new byte[nComponents][];
	for (int i = 0; i < nComponents; i++) {
		frameComponent = frameComponents[componentIds[i]];
		imageComponents[i] = new byte[frameComponent[CW] * frameComponent[CH]];
	}
	frameComponent = frameComponents[componentIds[ID_Y]];
	for (int yPos = 0; yPos < srcHeight; yPos++) {
		int srcOfs = yPos * srcWidth;
		int dstOfs = yPos * frameComponent[CW];
		System.arraycopy(dataYComp, srcOfs, imageComponents[ID_Y], dstOfs, srcWidth);
	}
	frameComponent = frameComponents[componentIds[ID_CB]];
	for (int yPos = 0; yPos < srcHeight / maxV; yPos++) {
		int destRowIndex = yPos * frameComponent[CW];
		for (int xPos = 0; xPos < srcWidth / maxH; xPos++) {
			int sum = 0;
			for (int iv = 0; iv < maxV; iv++) {
				int srcIndex = (yPos * maxV + iv) * srcWidth + (xPos * maxH);
				for (int ih = 0; ih < maxH; ih++) {
					sum += dataCbComp[srcIndex + ih] & 0xFF;
				}
			}
			imageComponents[ID_CB][destRowIndex + xPos] = (byte)(sum / vhFactor);
		}
	}
	frameComponent = frameComponents[componentIds[ID_CR]];
	for (int yPos = 0; yPos < srcHeight / maxV; yPos++) {
		int destRowIndex = yPos * frameComponent[CW];
		for (int xPos = 0; xPos < srcWidth / maxH; xPos++) {
			int sum = 0;
			for (int iv = 0; iv < maxV; iv++) {
				int srcIndex = (yPos * maxV + iv) * srcWidth + (xPos * maxH);
				for (int ih = 0; ih < maxH; ih++) {
					sum += dataCrComp[srcIndex + ih] & 0xFF;
				}
			}
			imageComponents[ID_CR][destRowIndex + xPos] = (byte)(sum / vhFactor);
		}
	}
	for (int iComp = 0; iComp < nComponents; iComp++) {
		byte[] imageComponent = imageComponents[iComp];
		frameComponent = frameComponents[componentIds[iComp]];
		int hFactor = frameComponent[HI];
		int vFactor = frameComponent[VI];
		int componentWidth = frameComponent[CW];
		int componentHeight = frameComponent[CH];
		int compressedWidth = srcWidth / (maxH / hFactor);
		int compressedHeight = srcHeight / (maxV / vFactor);
		if (compressedWidth < componentWidth) {
			int delta = componentWidth - compressedWidth;
			for (int yPos = 0; yPos < compressedHeight; yPos++) {
				int dstOfs = ((yPos + 1) * componentWidth - delta);
				int dataValue = imageComponent[dstOfs - 1] & 0xFF;
				for (int i = 0; i < delta; i++) {
					imageComponent[dstOfs + i] = (byte)dataValue;
				}
			}
		}
		if (compressedHeight < componentHeight) {
			int srcOfs = (compressedHeight - 1) * componentWidth;
			for (int yPos = compressedHeight; yPos <= componentHeight; yPos++) {
				int dstOfs = (yPos - 1) * componentWidth;
				System.arraycopy(imageComponent, srcOfs, imageComponent, dstOfs, componentWidth);
			}
		}
	}
}
void convert4BitRGBToYCbCr(ImageData image) {
	RGB[] rgbs = image.getRGBs();
	int paletteSize = rgbs.length;
	byte[] yComp = new byte[paletteSize];
	byte[] cbComp = new byte[paletteSize];
	byte[] crComp = new byte[paletteSize];
	int srcWidth = image.width;
	int srcHeight = image.height;
	for (int i = 0; i < paletteSize; i++) {
		RGB color = rgbs[i];
		int r = color.red;
		int g = color.green;
		int b = color.blue;
		int n = RYTable[r] + GYTable[g] + BYTable[b];
		yComp[i] = (byte)(n / 65536);
		if ((n < 0) && (n % 65536 != 0)) yComp[i]--;
		n = RCbTable[r] + GCbTable[g] + BCbTable[b];
		cbComp[i] = (byte)(n / 65536);
		if ((n < 0) && (n % 65536 != 0)) cbComp[i]--;
		n = RCrTable[r] + GCrTable[g] + BCrTable[b];
		crComp[i] = (byte)(n / 65536);
		if ((n < 0) && (n % 65536 != 0)) crComp[i]--;
	}
	int bSize = srcWidth * srcHeight;
	byte[] dataYComp = new byte[bSize];
	byte[] dataCbComp = new byte[bSize];
	byte[] dataCrComp = new byte[bSize];
	byte[] origData = image.data;
	for (int yPos = 0; yPos < srcHeight; yPos++) {
		for (int xPos = 0; xPos < srcWidth / 2; xPos++) {
			int srcIndex = yPos * (srcWidth / 2) + xPos;
			int dstIndex = yPos * srcWidth + (xPos * 2);
			int value2 = origData[srcIndex] & 0xFF;
			int value1 = value2 / 16;
			value2 = value2 % 16;
			dataYComp[dstIndex] = yComp[value1];
			dataCbComp[dstIndex] = cbComp[value1];
			dataCrComp[dstIndex] = crComp[value1];
			dataYComp[dstIndex + 1] = yComp[value2];
			dataCbComp[dstIndex + 1] = cbComp[value2];
			dataCrComp[dstIndex + 1] = crComp[value2];
		}
	}
	compress(image, dataYComp, dataCbComp, dataCrComp);
}
void convert8BitRGBToYCbCr(ImageData image) {
	RGB[] rgbs = image.getRGBs();
	int paletteSize = rgbs.length;
	byte[] yComp = new byte[paletteSize];
	byte[] cbComp = new byte[paletteSize];
	byte[] crComp = new byte[paletteSize];
	int srcWidth = image.width;
	int srcHeight = image.height;
	for (int i = 0; i < paletteSize; i++) {
		RGB color = rgbs[i];
		int r = color.red;
		int g = color.green;
		int b = color.blue;
		int n = RYTable[r] + GYTable[g] + BYTable[b];
		yComp[i] = (byte)(n / 65536);
		if ((n < 0) && (n % 65536 != 0)) yComp[i]--;
		n = RCbTable[r] + GCbTable[g] + BCbTable[b];
		cbComp[i] = (byte)(n / 65536);
		if ((n < 0) && (n % 65536 != 0)) cbComp[i]--;
		n = RCrTable[r] + GCrTable[g] + BCrTable[b];
		crComp[i] = (byte)(n / 65536);
		if ((n < 0) && (n % 65536 != 0)) crComp[i]--;
	}
	int dstWidth = image.width;
	int dstHeight = srcHeight;
	int stride = (srcWidth + 3) / 4 * 4;
	int bSize = dstWidth * dstHeight;
	byte[] dataYComp = new byte[bSize];
	byte[] dataCbComp = new byte[bSize];
	byte[] dataCrComp = new byte[bSize];
	byte[] origData = image.data;
	for (int yPos = 0; yPos < srcHeight; yPos++) {
		int srcRowIndex = yPos * stride;
		int dstRowIndex = yPos * dstWidth;
		for (int xPos = 0; xPos < srcWidth; xPos++) {
			int value = origData[srcRowIndex + xPos] & 0xFF;
			int dstIndex = dstRowIndex + xPos;
			dataYComp[dstIndex] = yComp[value];
			dataCbComp[dstIndex] = cbComp[value];
			dataCrComp[dstIndex] = crComp[value];
		}
	}
	compress(image, dataYComp, dataCbComp, dataCrComp);
}
byte[] convertCMYKToRGB() {
	/* Unsupported CMYK format. Answer an empty byte array. */
	return new byte[0];
}
void convertImageToYCbCr(ImageData image) {
	switch (image.depth) {
		case 4:
			convert4BitRGBToYCbCr(image);
			return;
		case 8:
			convert8BitRGBToYCbCr(image);
			return;
		case 16:
		case 24:
		case 32:
			convertMultiRGBToYCbCr(image);
			return;
		default:
			SWT.error(SWT.ERROR_UNSUPPORTED_DEPTH);
	}
	return;
}
void convertMultiRGBToYCbCr(ImageData image) {
	int srcWidth = image.width;
	int srcHeight = image.height;
	int bSize = srcWidth * srcHeight;
	byte[] dataYComp = new byte[bSize];
	byte[] dataCbComp = new byte[bSize];
	byte[] dataCrComp = new byte[bSize];
	PaletteData palette = image.palette;
	int[] buffer = new int[srcWidth];
	if (palette.isDirect) {
		int redMask = palette.redMask;
		int greenMask = palette.greenMask;
		int blueMask = palette.blueMask;
		int redShift = palette.redShift;
		int greenShift = palette.greenShift;
		int blueShift = palette.blueShift;
		for (int yPos = 0; yPos < srcHeight; yPos++) {
			image.getPixels(0, yPos, srcWidth, buffer, 0);
			int dstRowIndex = yPos * srcWidth;
			for (int xPos = 0; xPos < srcWidth; xPos++) {
				int pixel = buffer[xPos];
				int dstDataIndex = dstRowIndex + xPos;
				int r = pixel & redMask;
				r = (redShift < 0) ? r >>> -redShift : r << redShift;
				int g = pixel & greenMask;
				g = (greenShift < 0) ? g >>> -greenShift : g << greenShift;
				int b = pixel & blueMask;
				b = (blueShift < 0) ? b >>> -blueShift : b << blueShift;				
				dataYComp[dstDataIndex] = (byte)((RYTable[r] + GYTable[g] + BYTable[b]) / 65536);
				dataCbComp[dstDataIndex] = (byte)((RCbTable[r] + GCbTable[g] + BCbTable[b]) / 65536);
				dataCrComp[dstDataIndex] = (byte)((RCrTable[r] + GCrTable[g] + BCrTable[b]) / 65536);
			}
		}
	} else {
		for (int yPos = 0; yPos < srcHeight; yPos++) {
			image.getPixels(0, yPos, srcWidth, buffer, 0);
			int dstRowIndex = yPos * srcWidth;
			for (int xPos = 0; xPos < srcWidth; xPos++) {
				int pixel = buffer[xPos];
				int dstDataIndex = dstRowIndex + xPos;
				RGB rgb = palette.getRGB(pixel);
				int r = rgb.red;
				int g = rgb.green;
				int b = rgb.blue;
				dataYComp[dstDataIndex] = (byte)((RYTable[r] + GYTable[g] + BYTable[b]) / 65536);
				dataCbComp[dstDataIndex] = (byte)((RCbTable[r] + GCbTable[g] + BCbTable[b]) / 65536);
				dataCrComp[dstDataIndex] = (byte)((RCrTable[r] + GCrTable[g] + BCrTable[b]) / 65536);
			}
		}
	}
	compress(image, dataYComp, dataCbComp, dataCrComp);
}
byte[] convertYToRGB() {
	int compWidth = frameComponents[componentIds[ID_Y]][CW];
	int bytesPerLine = (((imageWidth * 8 + 7) / 8) + 3) / 4 * 4;
	byte[] data = new byte[bytesPerLine * imageHeight];
	byte[] yComp = imageComponents[ID_Y];
	int destIndex = 0;
	for (int i = 0; i < imageHeight; i++) {
		int srcIndex = i * compWidth;
		for (int j = 0; j < bytesPerLine; j++) {
			int y = yComp[srcIndex] & 0xFF;
			if (y < 0) {
				y = 0;
			} else {
				if (y > 255) y = 255;
			}
			if (j >= imageWidth) {
				y = 0;
			}
			data[destIndex] = (byte)y;
			srcIndex++;
			destIndex++;
		}
	}
	return data;
}
byte[] convertYCbCrToRGB() {
	/**
	 * Convert existing image components into an RGB format.
	 * YCbCr is defined per CCIR 601-1, except that Cb and Cr are
	 * normalized to the range 0..MAXJSAMPLE rather than -0.5 .. 0.5.
	 * The conversion equations to be implemented are therefore
	 * 	R = Y                + 1.40200 * Cr
	 * 	G = Y - 0.34414 * Cb - 0.71414 * Cr
	 * 	B = Y + 1.77200 * Cb
	 * where Cb and Cr represent the incoming values less MAXJSAMPLE/2.
	 * (These numbers are derived from TIFF 6.0 section 21, dated 3-June-92.)
	 * 
	 * To avoid floating-point arithmetic, we represent the fractional constants
	 * as integers scaled up by 2^16 (about 4 digits precision); we have to divide
	 * the products by 2^16, with appropriate rounding, to get the correct answer.
	 * Notice that Y, being an integral input, does not contribute any fraction
	 * so it need not participate in the rounding.
	 * 
	 * For even more speed, we avoid doing any multiplications in the inner loop
	 * by precalculating the constants times Cb and Cr for all possible values.
	 * For 8-bit JSAMPLEs this is very reasonable (only 256 entries per table);
	 * for 12-bit samples it is still acceptable.  It's not very reasonable for
	 * 16-bit samples, but if you want lossless storage you shouldn't be changing
	 * colorspace anyway.
	 * The Cr=>R and Cb=>B values can be rounded to integers in advance; the
	 * values for the G calculation are left scaled up, since we must add them
	 * together before rounding.
	 */
	int bSize = imageWidth * imageHeight * nComponents;
	byte[] rgbData = new byte[bSize];
	int destIndex = 0;
	expandImageComponents();
	byte[] yComp = imageComponents[ID_Y];
	byte[] cbComp = imageComponents[ID_CB];
	byte[] crComp = imageComponents[ID_CR];
	int compWidth = frameComponents[componentIds[ID_Y]][CW];
	for (int v = 0; v < imageHeight; v++) {
		int srcIndex = v * compWidth;
		for (int i = 0; i < imageWidth; i++) {
			int y = yComp[srcIndex] & 0xFF;
			int cb = cbComp[srcIndex] & 0xFF;
			int cr = crComp[srcIndex] & 0xFF;
			int r = y + CrRTable[cr];
			int g = y + ((CbGTable[cb] + CrGTable[cr]) / 65536);
			int b = y + CbBTable[cb];
			if (r < 0) {
				r = 0;
			} else {
				if (r > 255) r = 255;
			}
			if (g < 0) {
				g = 0;
			} else {
				if (g > 255) g = 255;
			}
			if (b < 0) {
				b = 0;
			} else {
				if (b > 255) b = 255;
			}
			rgbData[destIndex] = (byte)b;
			rgbData[destIndex + 1] = (byte)g;
			rgbData[destIndex + 2] = (byte)r;
			destIndex += 3;
			srcIndex++;
		}
	}
	return rgbData;
}
byte[] convertYIQToRGB() {
	/* Unsupported CMYK format. Answer an empty byte array. */
	return new byte[0];
}
void decodeACCoefficients(int[] dataUnit, int iComp) {
	int[] sParams = scanHeader.componentParameters[componentIds[iComp]];
	JPEGHuffmanTable acTable = acHuffmanTables[sParams[AC]];