public BufferedImage read(int imageIndex, ImageReadParam param) throws IOException {
checkIndex(imageIndex);
readHeader();
if (iis == null) throw new IllegalStateException("input is null");
BufferedImage img;
clearAbortRequest();
processImageStarted(imageIndex);
if (param == null) param = getDefaultReadParam();
sourceRegion = new Rectangle(0, 0, 0, 0);
destinationRegion = new Rectangle(0, 0, 0, 0);
computeRegions(
param, this.width, this.height, param.getDestination(), sourceRegion, destinationRegion);
scaleX = param.getSourceXSubsampling();
scaleY = param.getSourceYSubsampling();
// If the destination band is set used it
sourceBands = param.getSourceBands();
destBands = param.getDestinationBands();
seleBand = (sourceBands != null) && (destBands != null);
noTransform = destinationRegion.equals(new Rectangle(0, 0, width, height)) || seleBand;
if (!seleBand) {
sourceBands = new int[colorPlanes];
destBands = new int[colorPlanes];
for (int i = 0; i < colorPlanes; i++) destBands[i] = sourceBands[i] = i;
}
// If the destination is provided, then use it. Otherwise, create new one
bi = param.getDestination();
// Get the image data.
WritableRaster raster = null;
if (bi == null) {
if (sampleModel != null && colorModel != null) {
sampleModel =
sampleModel.createCompatibleSampleModel(
destinationRegion.width + destinationRegion.x,
destinationRegion.height + destinationRegion.y);
if (seleBand) sampleModel = sampleModel.createSubsetSampleModel(sourceBands);
raster = Raster.createWritableRaster(sampleModel, new Point(0, 0));
bi = new BufferedImage(colorModel, raster, false, null);
}
} else {
raster = bi.getWritableTile(0, 0);
sampleModel = bi.getSampleModel();
colorModel = bi.getColorModel();
noTransform &= destinationRegion.equals(raster.getBounds());
}
byte bdata[] = null; // buffer for byte data
if (sampleModel.getDataType() == DataBuffer.TYPE_BYTE)
bdata = (byte[]) ((DataBufferByte) raster.getDataBuffer()).getData();
readImage(bdata);
if (abortRequested()) processReadAborted();
else processImageComplete();
return bi;
}
