private void writeBlocks(byte[] data) throws IOException {
if (data != null && data.length > 0) {
int offset = 0;
while (offset < data.length) {
int len = Math.min(data.length - offset, 255);
stream.write(len);
stream.write(data, offset, len);
offset += len;
}
}
}
private void writeCommentExtension(GIFWritableImageMetadata im) throws IOException {
if (im.comments != null) {
try {
Iterator iter = im.comments.iterator();
while (iter.hasNext()) {
stream.write(0x21);
stream.write(0xfe);
writeBlocks((byte[]) iter.next());
stream.write(0x00);
}
} catch (IOException e) {
throw new IIOException("I/O error writing Comment Extension!", e);
}
}
}
private void writeGraphicControlExtension(
int disposalMethod,
boolean userInputFlag,
boolean transparentColorFlag,
int delayTime,
int transparentColorIndex)
throws IOException {
try {
stream.write(0x21);
stream.write(0xf9);
stream.write(4);
int packedFields = (disposalMethod & 0x3) << 2;
if (userInputFlag) {
packedFields |= 0x2;
}
if (transparentColorFlag) {
packedFields |= 0x1;
}
stream.write(packedFields);
stream.writeShort((short) delayTime);
stream.write(transparentColorIndex);
stream.write(0x00);
} catch (IOException e) {
throw new IIOException("I/O error writing Graphic Control Extension!", e);
}
}
private void writeApplicationExtension(GIFWritableImageMetadata im) throws IOException {
if (im.applicationIDs != null) {
Iterator iterIDs = im.applicationIDs.iterator();
Iterator iterCodes = im.authenticationCodes.iterator();
Iterator iterData = im.applicationData.iterator();
while (iterIDs.hasNext()) {
try {
stream.write(0x21);
stream.write(0xff);
stream.write(11);
stream.write((byte[]) iterIDs.next(), 0, 8);
stream.write((byte[]) iterCodes.next(), 0, 3);
writeBlocks((byte[]) iterData.next());
stream.write(0x00);
} catch (IOException e) {
throw new IIOException("I/O error writing Application Extension!", e);
}
}
}
}
private void writeHeader(
String version,
int logicalScreenWidth,
int logicalScreenHeight,
int colorResolution,
int pixelAspectRatio,
int backgroundColorIndex,
boolean sortFlag,
int bitsPerPixel,
byte[] globalColorTable)
throws IOException {
try {
// Signature
stream.writeBytes("GIF" + version);
// Screen Descriptor
// Width
stream.writeShort((short) logicalScreenWidth);
// Height
stream.writeShort((short) logicalScreenHeight);
// Global Color Table
// Packed fields
int packedFields = globalColorTable != null ? 0x80 : 0x00;
packedFields |= ((colorResolution - 1) & 0x7) << 4;
if (sortFlag) {
packedFields |= 0x8;
}
packedFields |= (bitsPerPixel - 1);
stream.write(packedFields);
// Background color index
stream.write(backgroundColorIndex);
// Pixel aspect ratio
stream.write(pixelAspectRatio);
// Global Color Table
if (globalColorTable != null) {
stream.write(globalColorTable);
}
} catch (IOException e) {
throw new IIOException("I/O error writing header!", e);
}
}
private void writeImageDescriptor(
int imageLeftPosition,
int imageTopPosition,
int imageWidth,
int imageHeight,
boolean interlaceFlag,
boolean sortFlag,
int bitsPerPixel,
byte[] localColorTable)
throws IOException {
try {
stream.write(0x2c);
stream.writeShort((short) imageLeftPosition);
stream.writeShort((short) imageTopPosition);
stream.writeShort((short) imageWidth);
stream.writeShort((short) imageHeight);
int packedFields = localColorTable != null ? 0x80 : 0x00;
if (interlaceFlag) {
packedFields |= 0x40;
}
if (sortFlag) {
packedFields |= 0x8;
}
packedFields |= (bitsPerPixel - 1);
stream.write(packedFields);
if (localColorTable != null) {
stream.write(localColorTable);
}
} catch (IOException e) {
throw new IIOException("I/O error writing Image Descriptor!", e);
}
}
private void writeRasterData(
RenderedImage image,
Rectangle sourceBounds,
Dimension destSize,
ImageWriteParam param,
boolean interlaceFlag)
throws IOException {
int sourceXOffset = sourceBounds.x;
int sourceYOffset = sourceBounds.y;
int sourceWidth = sourceBounds.width;
int sourceHeight = sourceBounds.height;
int destWidth = destSize.width;
int destHeight = destSize.height;
int periodX;
int periodY;
if (param == null) {
periodX = 1;
periodY = 1;
} else {
periodX = param.getSourceXSubsampling();
periodY = param.getSourceYSubsampling();
}
SampleModel sampleModel = image.getSampleModel();
int bitsPerPixel = sampleModel.getSampleSize()[0];
int initCodeSize = bitsPerPixel;
if (initCodeSize == 1) {
initCodeSize++;
}
stream.write(initCodeSize);
LZWCompressor compressor = new LZWCompressor(stream, initCodeSize, false);
boolean isOptimizedCase =
periodX == 1
&& periodY == 1
&& sampleModel instanceof ComponentSampleModel
&& image.getNumXTiles() == 1
&& image.getNumYTiles() == 1
&& image.getTile(0, 0).getDataBuffer() instanceof DataBufferByte;
int numRowsWritten = 0;
int progressReportRowPeriod = Math.max(destHeight / 20, 1);
processImageStarted(imageIndex);
if (interlaceFlag) {
if (DEBUG) System.out.println("Writing interlaced");
if (isOptimizedCase) {
Raster tile = image.getTile(0, 0);
byte[] data = ((DataBufferByte) tile.getDataBuffer()).getData();
ComponentSampleModel csm = (ComponentSampleModel) tile.getSampleModel();
int offset = csm.getOffset(sourceXOffset, sourceYOffset, 0);
int lineStride = csm.getScanlineStride();
writeRowsOpt(
data,
offset,
lineStride,
compressor,
0,
8,
destWidth,
destHeight,
numRowsWritten,
progressReportRowPeriod);
if (abortRequested()) {
return;
}
numRowsWritten += destHeight / 8;
writeRowsOpt(
data,
offset,
lineStride,
compressor,
4,
8,
destWidth,
destHeight,
numRowsWritten,
progressReportRowPeriod);
if (abortRequested()) {
return;
}
numRowsWritten += (destHeight - 4) / 8;
writeRowsOpt(
data,
offset,
lineStride,
compressor,
2,
4,
destWidth,
destHeight,
numRowsWritten,
progressReportRowPeriod);
if (abortRequested()) {
return;
}
numRowsWritten += (destHeight - 2) / 4;
writeRowsOpt(
data,
offset,
lineStride,
compressor,
1,
2,
destWidth,
destHeight,
numRowsWritten,
progressReportRowPeriod);
} else {
writeRows(
image,
compressor,
sourceXOffset,
periodX,
sourceYOffset,
8 * periodY,
sourceWidth,
0,
8,
destWidth,
destHeight,
numRowsWritten,
progressReportRowPeriod);
if (abortRequested()) {
return;
}
numRowsWritten += destHeight / 8;
writeRows(
image,
compressor,
sourceXOffset,
periodX,
sourceYOffset + 4 * periodY,
8 * periodY,
sourceWidth,
4,
8,
destWidth,
destHeight,
numRowsWritten,
progressReportRowPeriod);
if (abortRequested()) {
return;
}
numRowsWritten += (destHeight - 4) / 8;
writeRows(
image,
compressor,
sourceXOffset,
periodX,
sourceYOffset + 2 * periodY,
4 * periodY,
sourceWidth,
2,
4,
destWidth,
destHeight,
numRowsWritten,
progressReportRowPeriod);
if (abortRequested()) {
return;
}
numRowsWritten += (destHeight - 2) / 4;
writeRows(
image,
compressor,
sourceXOffset,
periodX,
sourceYOffset + periodY,
2 * periodY,
sourceWidth,
1,
2,
destWidth,
destHeight,
numRowsWritten,
progressReportRowPeriod);
}
} else {
if (DEBUG) System.out.println("Writing non-interlaced");
if (isOptimizedCase) {
Raster tile = image.getTile(0, 0);
byte[] data = ((DataBufferByte) tile.getDataBuffer()).getData();
ComponentSampleModel csm = (ComponentSampleModel) tile.getSampleModel();
int offset = csm.getOffset(sourceXOffset, sourceYOffset, 0);
int lineStride = csm.getScanlineStride();
writeRowsOpt(
data,
offset,
lineStride,
compressor,
0,
1,
destWidth,
destHeight,
numRowsWritten,
progressReportRowPeriod);
} else {
writeRows(
image,
compressor,
sourceXOffset,
periodX,
sourceYOffset,
periodY,
sourceWidth,
0,
1,
destWidth,
destHeight,
numRowsWritten,
progressReportRowPeriod);
}
}
if (abortRequested()) {
return;
}
processImageProgress(100.0F);
compressor.flush();
stream.write(0x00);
processImageComplete();
}
private void writeTrailer() throws IOException {
stream.write(0x3b);
}
private void writePlainTextExtension(GIFWritableImageMetadata im) throws IOException {
if (im.hasPlainTextExtension) {
try {
stream.write(0x21);
stream.write(0x1);
stream.write(12);
stream.writeShort(im.textGridLeft);
stream.writeShort(im.textGridTop);
stream.writeShort(im.textGridWidth);
stream.writeShort(im.textGridHeight);
stream.write(im.characterCellWidth);
stream.write(im.characterCellHeight);
stream.write(im.textForegroundColor);
stream.write(im.textBackgroundColor);
writeBlocks(im.text);
stream.write(0x00);
} catch (IOException e) {
throw new IIOException("I/O error writing Plain Text Extension!", e);
}
}
}