public BufferedImage read(int imageIndex, ImageReadParam param) throws IOException {
BufferedImage dst = null;
try {
// Calculate and return a Rectangle that identifies the region of
// the
// source image that should be read:
//
// 1. If param is null, the upper-left corner of the region is (0,
// 0),
// and the width and height are specified by the width and height
// arguments. In other words, the entire image is read.
//
// 2. If param is not null
//
// 2.1 If param.getSourceRegion() returns a non-null Rectangle, the
// region is calculated as the intersection of param's Rectangle
// and the earlier (0, 0, width, height Rectangle).
//
// 2.2 param.getSubsamplingXOffset() is added to the region's x
// coordinate and subtracted from its width.
//
// 2.3 param.getSubsamplingYOffset() is added to the region's y
// coordinate and subtracted from its height.
int width = getWidth(imageIndex);
int height = getHeight(imageIndex);
Rectangle sourceRegion = getSourceRegion(param, width, height);
// Source subsampling is used to return a scaled-down source image.
// Default 1 values for X and Y subsampling indicate that a
// non-scaled
// source image will be returned.
int sourceXSubsampling = 1;
int sourceYSubsampling = 1;
// The destination offset determines the starting location in the
// destination where decoded pixels are placed. Default (0, 0)
// values indicate the upper-left corner.
Point destinationOffset = new Point(0, 0);
// If param is not null, override the source subsampling, and
// destination offset defaults.
if (param != null) {
sourceXSubsampling = param.getSourceXSubsampling();
sourceYSubsampling = param.getSourceYSubsampling();
destinationOffset = param.getDestinationOffset();
}
// Obtain a BufferedImage into which decoded pixels will be placed.
// This destination will be returned to the application.
//
// 1. If param is not null
//
// 1.1 If param.getDestination() returns a BufferedImage
//
// 1.1.1 Return this BufferedImage
//
// Else
//
// 1.1.2 Invoke param.getDestinationType ().
//
// 1.1.3 If the returned ImageTypeSpecifier equals
// getImageTypes (0) (see below), return its BufferedImage.
//
// 2. If param is null or a BufferedImage has not been obtained
//
// 2.1 Return getImageTypes (0)'s BufferedImage.
dst = getDestination(param, getImageTypes(0), width, height);
// Create a WritableRaster for the destination.
WritableRaster wrDst = dst.getRaster();
JBIG2Bitmap bitmap =
decoder
.getPageAsJBIG2Bitmap(imageIndex)
.getSlice(sourceRegion.x, sourceRegion.y, sourceRegion.width, sourceRegion.height);
BufferedImage image = bitmap.getBufferedImage();
int newWidth = (int) (image.getWidth() * (1 / (double) sourceXSubsampling));
int newHeight = (int) (image.getHeight() * (1 / (double) sourceYSubsampling));
BufferedImage scaledImage = scaleImage(image.getRaster(), newWidth, newHeight, 1, 1);
Raster raster = null;
if (scaledImage != null) {
raster = scaledImage.getRaster();
} else raster = image.getRaster();
wrDst.setRect(destinationOffset.x, destinationOffset.y, raster);
} catch (RuntimeException e) {
e.printStackTrace();
}
return dst;
}
