/**
* Compute the source region and destination dimensions taking any parameter settings into
* account.
*/
private static void computeRegions(
Rectangle sourceBounds, Dimension destSize, ImageWriteParam p) {
ImageWriteParam param;
int periodX = 1;
int periodY = 1;
if (p != null) {
int[] sourceBands = p.getSourceBands();
if (sourceBands != null && (sourceBands.length != 1 || sourceBands[0] != 0)) {
throw new IllegalArgumentException("Cannot sub-band image!");
}
// Get source region and subsampling factors
Rectangle sourceRegion = p.getSourceRegion();
if (sourceRegion != null) {
// Clip to actual image bounds
sourceRegion = sourceRegion.intersection(sourceBounds);
sourceBounds.setBounds(sourceRegion);
}
// Adjust for subsampling offsets
int gridX = p.getSubsamplingXOffset();
int gridY = p.getSubsamplingYOffset();
sourceBounds.x += gridX;
sourceBounds.y += gridY;
sourceBounds.width -= gridX;
sourceBounds.height -= gridY;
// Get subsampling factors
periodX = p.getSourceXSubsampling();
periodY = p.getSourceYSubsampling();
}
// Compute output dimensions
destSize.setSize(
(sourceBounds.width + periodX - 1) / periodX,
(sourceBounds.height + periodY - 1) / periodY);
if (destSize.width <= 0 || destSize.height <= 0) {
throw new IllegalArgumentException("Empty source region!");
}
}
public BufferedImage read(int imageIndex, ImageReadParam param) throws IOException {
if (iis == null) {
throw new IllegalStateException(I18N.getString("WBMPImageReader1"));
}
checkIndex(imageIndex);
clearAbortRequest();
processImageStarted(imageIndex);
if (param == null) param = getDefaultReadParam();
// read header
readHeader();
Rectangle sourceRegion = new Rectangle(0, 0, 0, 0);
Rectangle destinationRegion = new Rectangle(0, 0, 0, 0);
computeRegions(
param, this.width, this.height, param.getDestination(), sourceRegion, destinationRegion);
int scaleX = param.getSourceXSubsampling();
int scaleY = param.getSourceYSubsampling();
int xOffset = param.getSubsamplingXOffset();
int yOffset = param.getSubsamplingYOffset();
// If the destination is provided, then use it. Otherwise, create new one
BufferedImage bi = param.getDestination();
if (bi == null)
bi =
new BufferedImage(
destinationRegion.x + destinationRegion.width,
destinationRegion.y + destinationRegion.height,
BufferedImage.TYPE_BYTE_BINARY);
boolean noTransform =
destinationRegion.equals(new Rectangle(0, 0, width, height))
&& destinationRegion.equals(new Rectangle(0, 0, bi.getWidth(), bi.getHeight()));
// Get the image data.
WritableRaster tile = bi.getWritableTile(0, 0);
// Get the SampleModel.
MultiPixelPackedSampleModel sm = (MultiPixelPackedSampleModel) bi.getSampleModel();
if (noTransform) {
if (abortRequested()) {
processReadAborted();
return bi;
}
// If noTransform is necessary, read the data.
iis.read(
((DataBufferByte) tile.getDataBuffer()).getData(), 0, height * sm.getScanlineStride());
processImageUpdate(bi, 0, 0, width, height, 1, 1, new int[] {0});
processImageProgress(100.0F);
} else {
int len = (this.width + 7) / 8;
byte[] buf = new byte[len];
byte[] data = ((DataBufferByte) tile.getDataBuffer()).getData();
int lineStride = sm.getScanlineStride();
iis.skipBytes(len * sourceRegion.y);
int skipLength = len * (scaleY - 1);
// cache the values to avoid duplicated computation
int[] srcOff = new int[destinationRegion.width];
int[] destOff = new int[destinationRegion.width];
int[] srcPos = new int[destinationRegion.width];
int[] destPos = new int[destinationRegion.width];
for (int i = destinationRegion.x, x = sourceRegion.x, j = 0;
i < destinationRegion.x + destinationRegion.width;
i++, j++, x += scaleX) {
srcPos[j] = x >> 3;
srcOff[j] = 7 - (x & 7);
destPos[j] = i >> 3;
destOff[j] = 7 - (i & 7);
}
for (int j = 0, y = sourceRegion.y, k = destinationRegion.y * lineStride;
j < destinationRegion.height;
j++, y += scaleY) {
if (abortRequested()) break;
iis.read(buf, 0, len);
for (int i = 0; i < destinationRegion.width; i++) {
// get the bit and assign to the data buffer of the raster
int v = (buf[srcPos[i]] >> srcOff[i]) & 1;
data[k + destPos[i]] |= v << destOff[i];
}
k += lineStride;
iis.skipBytes(skipLength);
processImageUpdate(bi, 0, j, destinationRegion.width, 1, 1, 1, new int[] {0});
processImageProgress(100.0F * j / destinationRegion.height);
}
}
if (abortRequested()) processReadAborted();
else processImageComplete();
return bi;
}