tiffdirectory.java

源码为Eclipse开源开发平台桌面开发工具SWT的源代码,

				break;
			}
			case TAG_Compression: {
				compression = getEntryValue(type, buffer, offset);
				break;
			}
			case TAG_PhotometricInterpretation: {
				photometricInterpretation = getEntryValue(type, buffer, offset);
				break;
			}
			case TAG_StripOffsets: {
				if (type != TYPE_LONG && type != TYPE_SHORT) SWT.error(SWT.ERROR_INVALID_IMAGE);
				stripOffsets = new int[count];
				getEntryValue(type, buffer, offset, stripOffsets);
				break;
			}
			case TAG_SamplesPerPixel: {
				if (type != TYPE_SHORT) SWT.error(SWT.ERROR_INVALID_IMAGE);
				samplesPerPixel = getEntryValue(type, buffer, offset);
				/* Only the basic 1 and 3 values are supported */
				if (samplesPerPixel != 1 && samplesPerPixel != 3) SWT.error(SWT.ERROR_UNSUPPORTED_DEPTH);
				break;
			}
			case TAG_RowsPerStrip: {
				rowsPerStrip = getEntryValue(type, buffer, offset);
				break;
			}
			case TAG_StripByteCounts: {
				stripByteCounts = new int[count];
				getEntryValue(type, buffer, offset, stripByteCounts);
				break;
			}
			case TAG_XResolution: {
				/* Ignored */
				break;
			}
			case TAG_YResolution: {
				/* Ignored */
				break;
			}
			case TAG_T4Options: {
				if (type != TYPE_LONG) SWT.error(SWT.ERROR_INVALID_IMAGE);
				t4Options = getEntryValue(type, buffer, offset);
				if ((t4Options & 0x1) == 1) {
					/* 2-dimensional coding is not supported */
					SWT.error(SWT.ERROR_UNSUPPORTED_FORMAT);
				}
				break;
			}
			case TAG_ResolutionUnit: {
				/* Ignored */
				break;
			}
			case TAG_ColorMap: {
				if (type != TYPE_SHORT) SWT.error(SWT.ERROR_INVALID_IMAGE);
				/* Get the offset of the colorMap (use TYPE_LONG) */
				colorMapOffset = getEntryValue(TYPE_LONG, buffer, offset);
				break;
			}
		}
	}
}

public ImageData read() throws IOException {
	/* Set TIFF default values */
	bitsPerSample = new int[] {1};
	colorMapOffset = NO_VALUE;
	compression = 1;
	imageLength = NO_VALUE;
	imageWidth = NO_VALUE;
	photometricInterpretation = NO_VALUE;
	rowsPerStrip = Integer.MAX_VALUE;
	samplesPerPixel = 1;
	stripByteCounts = null;
	stripOffsets = null;
	
	byte[] buffer = new byte[2];
	file.read(buffer);
	int numberEntries = toInt(buffer, 0, TYPE_SHORT);
	buffer = new byte[IFD_ENTRY_SIZE * numberEntries];
	file.read(buffer);
	parseEntries(buffer);
	
	PaletteData palette = null;
	depth = 0;
	switch (photometricInterpretation) {
		case 0:
		case 1: {
			/* Bilevel or Grayscale image */
			palette = getGrayPalette();
			depth = bitsPerSample[0];
			break;
		}
		case 2: {
			/* RGB image */
			if (colorMapOffset != NO_VALUE) SWT.error(SWT.ERROR_INVALID_IMAGE);
			/* SamplesPerPixel 3 is the only value supported */
			palette = getRGBPalette(bitsPerSample[0], bitsPerSample[1], bitsPerSample[2]);
			depth = bitsPerSample[0] + bitsPerSample[1] + bitsPerSample[2];
			break;		
		}
		case 3: {
			/* Palette Color image */
			if (colorMapOffset == NO_VALUE) SWT.error(SWT.ERROR_INVALID_IMAGE);
			palette = getColorMap();
			depth = bitsPerSample[0];
			break;
		}
		default: {
			SWT.error(SWT.ERROR_INVALID_IMAGE);
		}
	}

	ImageData image = ImageData.internal_new(
			imageWidth,
			imageLength, 
			depth,
			palette,
			1,
			null,
			0,
			null,
			null,
			-1,
			-1,
			SWT.IMAGE_TIFF,
			0,
			0,
			0,
			0);
	decodePixels(image);
	return image;
}

int toInt(byte[] buffer, int i, int type) {
	if (type == TYPE_LONG) {
		return isLittleEndian ? 
		(buffer[i] & 0xFF) | ((buffer[i + 1] & 0xFF) << 8) | ((buffer[i + 2] & 0xFF) << 16) | ((buffer[i + 3] & 0xFF) << 24) :
		(buffer[i + 3] & 0xFF) | ((buffer[i + 2] & 0xFF) << 8) | ((buffer[i + 1] & 0xFF) << 16) | ((buffer[i] & 0xFF) << 24);
	}
	if (type == TYPE_SHORT) {
		return isLittleEndian ? 
		(buffer[i] & 0xFF) | ((buffer[i + 1] & 0xFF) << 8) :
		(buffer[i + 1] & 0xFF) | ((buffer[i] & 0xFF) << 8);		
	}
	/* Invalid type */
	SWT.error(SWT.ERROR_INVALID_IMAGE);
	return -1;
}

void write(int photometricInterpretation) throws IOException {
	boolean isRGB = photometricInterpretation == 2;
	boolean isColorMap = photometricInterpretation == 3;
	boolean isBiLevel = photometricInterpretation == 0 || photometricInterpretation == 1;

	int imageWidth = image.width;
	int imageLength = image.height;
	int rowByteSize = image.bytesPerLine;
	
	int numberEntries = isBiLevel ? 9 : 11;
	int lengthDirectory = 2 + 12 * numberEntries + 4;
	/* Offset following the header and the directory */
	int nextOffset = 8 + lengthDirectory;

	/* Extra space used by XResolution and YResolution values */
	int extraBytes = 16;

	int[] colorMap = null;
	if (isColorMap) {	
		PaletteData palette = image.palette;
		RGB[] rgbs = palette.getRGBs();
		colorMap = formatColorMap(rgbs);
		/* The number of entries of the Color Map must match the bitsPerSample field */
		if (colorMap.length != 3 * 1 << image.depth) SWT.error(SWT.ERROR_UNSUPPORTED_FORMAT);
		/* Extra space used by ColorMap values */
		extraBytes += colorMap.length * 2;
	}
	if (isRGB) {
		/* Extra space used by BitsPerSample values */
		extraBytes += 6;
	} 
	/* TIFF recommends storing the data in strips of no more than 8 Ko */
	byte[] data = image.data;
	int[][] strips = new int[2][];
	int nbrRowsPerStrip = formatStrips(rowByteSize, imageLength, data, 8192, nextOffset, extraBytes, strips);
	int[] stripOffsets = strips[0];
	int[] stripByteCounts = strips[1];

	int bitsPerSampleOffset = NO_VALUE;
	if (isRGB) {
		bitsPerSampleOffset = nextOffset;
		nextOffset += 6;
	}
	int stripOffsetsOffset = NO_VALUE, stripByteCountsOffset = NO_VALUE;
	int xResolutionOffset, yResolutionOffset, colorMapOffset = NO_VALUE;
	int cnt = stripOffsets.length;
	if (cnt > 1) {
		stripOffsetsOffset = nextOffset;
		nextOffset += 4 * cnt;
		stripByteCountsOffset = nextOffset;
		nextOffset += 4 * cnt;
	}
	xResolutionOffset = nextOffset;
	nextOffset += 8;
	yResolutionOffset = nextOffset;
	nextOffset += 8;
	if (isColorMap) {
		colorMapOffset = nextOffset;
		nextOffset += colorMap.length * 2;
	}
	/* TIFF header */
	writeHeader();
	
	/* Image File Directory */
	out.writeShort(numberEntries);	
	writeEntry(TAG_ImageWidth, TYPE_LONG, 1, imageWidth);	
	writeEntry(TAG_ImageLength, TYPE_LONG, 1, imageLength);
	if (isColorMap) writeEntry(TAG_BitsPerSample, TYPE_SHORT, 1, image.depth);
	if (isRGB) writeEntry(TAG_BitsPerSample, TYPE_SHORT, 3, bitsPerSampleOffset);
	writeEntry(TAG_Compression, TYPE_SHORT, 1, COMPRESSION_NONE);
	writeEntry(TAG_PhotometricInterpretation, TYPE_SHORT, 1, photometricInterpretation);
	writeEntry(TAG_StripOffsets, TYPE_LONG, cnt, cnt > 1 ? stripOffsetsOffset : stripOffsets[0]);
	if (isRGB) writeEntry(TAG_SamplesPerPixel, TYPE_SHORT, 1, 3);
	writeEntry(TAG_RowsPerStrip, TYPE_LONG, 1, nbrRowsPerStrip);
	writeEntry(TAG_StripByteCounts, TYPE_LONG, cnt, cnt > 1 ? stripByteCountsOffset : stripByteCounts[0]);
	writeEntry(TAG_XResolution, TYPE_RATIONAL, 1, xResolutionOffset);
	writeEntry(TAG_YResolution, TYPE_RATIONAL, 1, yResolutionOffset);
	if (isColorMap) writeEntry(TAG_ColorMap, TYPE_SHORT, colorMap.length, colorMapOffset);
	/* Offset of next IFD (0 for last IFD) */
	out.writeInt(0);
	
	/* Values longer than 4 bytes Section */
	
	/* BitsPerSample 8,8,8 */
	if (isRGB) for (int i = 0; i < 3; i++) out.writeShort(8);
	if (cnt > 1) {
		for (int i = 0; i < cnt; i++) out.writeInt(stripOffsets[i]);
		for (int i = 0; i < cnt; i++) out.writeInt(stripByteCounts[i]);
	}
	/* XResolution and YResolution set to 300 dpi */
	for (int i = 0; i < 2; i++) {
		out.writeInt(300);
		out.writeInt(1);
	}
	/* ColorMap */
	if (isColorMap) for (int i = 0; i < colorMap.length; i++) out.writeShort(colorMap[i]);
	
	/* Image Data */
	out.write(data);
}

void writeEntry(short tag, int type, int count, int value) throws IOException {
	out.writeShort(tag);
	out.writeShort(type);
	out.writeInt(count);
	out.writeInt(value);
}

void writeHeader() throws IOException {
	/* little endian */
	out.writeByte((byte)0x49);
	out.writeByte((byte)0x49);

	/* TIFF identifier */
	out.writeShort(42);
	/* 
	* Offset of the first IFD is chosen to be 8.
	* It is word aligned and immediately after this header.
	*/
	out.writeInt(8);
}

void writeToStream(LEDataOutputStream byteStream) throws IOException {
	out = byteStream;
	int photometricInterpretation = -1;
	
	/* Scanline pad must be 1 */
	if (image.scanlinePad != 1) SWT.error(SWT.ERROR_UNSUPPORTED_FORMAT);
	switch (image.depth) {
		case 1: {
			/* Palette must be black and white or white and black */
			PaletteData palette = image.palette;
			RGB[] rgbs = palette.colors;
			if (palette.isDirect || rgbs == null || rgbs.length != 2) SWT.error(SWT.ERROR_UNSUPPORTED_FORMAT);
			RGB rgb0 = rgbs[0];
			RGB rgb1 = rgbs[1];
			if (!(rgb0.red == rgb0.green && rgb0.green == rgb0.blue &&
				rgb1.red == rgb1.green && rgb1.green == rgb1.blue &&
				((rgb0.red == 0x0 && rgb1.red == 0xFF) || (rgb0.red == 0xFF && rgb1.red == 0x0)))) {
				SWT.error(SWT.ERROR_UNSUPPORTED_FORMAT); 
			}
			/* 0 means a color index of 0 is imaged as white */
			photometricInterpretation = image.palette.colors[0].red == 0xFF ? 0 : 1;
			break;
		}
		case 4:
		case 8: {
			photometricInterpretation = 3;
			break;
		}
		case 24: {
			photometricInterpretation = 2;
			break;
		}
		default: {
			SWT.error(SWT.ERROR_UNSUPPORTED_FORMAT);
		}
	}
	write(photometricInterpretation);
}

}