private void readHeader() throws IOException {
if (gotHeader) {
iis.seek(128);
return;
}
metadata = new PCXMetadata();
manufacturer = iis.readByte(); // manufacturer
if (manufacturer != MANUFACTURER) throw new IllegalStateException("image is not a PCX file");
metadata.version = iis.readByte(); // version
encoding = iis.readByte(); // encoding
if (encoding != ENCODING)
throw new IllegalStateException("image is not a PCX file, invalid encoding " + encoding);
metadata.bitsPerPixel = iis.readByte();
metadata.xmin = iis.readShort();
metadata.ymin = iis.readShort();
xmax = iis.readShort();
ymax = iis.readShort();
metadata.hdpi = iis.readShort();
metadata.vdpi = iis.readShort();
iis.readFully(smallPalette);
iis.readByte(); // reserved
colorPlanes = iis.readByte();
bytesPerLine = iis.readShort();
paletteType = iis.readShort();
metadata.hsize = iis.readShort();
metadata.vsize = iis.readShort();
iis.skipBytes(54); // skip filler
width = xmax - metadata.xmin + 1;
height = ymax - metadata.ymin + 1;
if (colorPlanes == 1) {
if (paletteType == PALETTE_GRAYSCALE) {
ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_GRAY);
int[] nBits = {8};
colorModel =
new ComponentColorModel(
cs, nBits, false, false, Transparency.OPAQUE, DataBuffer.TYPE_BYTE);
sampleModel =
new ComponentSampleModel(DataBuffer.TYPE_BYTE, width, height, 1, width, new int[] {0});
} else {
if (metadata.bitsPerPixel == 8) {
// read palette from end of file, then reset back to image data
iis.mark();
if (iis.length() == -1) {
// read until eof, and work backwards
while (iis.read() != -1) ;
iis.seek(iis.getStreamPosition() - 256 * 3 - 1);
} else {
iis.seek(iis.length() - 256 * 3 - 1);
}
int palletteMagic = iis.read();
if (palletteMagic != 12)
processWarningOccurred(
"Expected palette magic number 12; instead read "
+ palletteMagic
+ " from this image.");
iis.readFully(largePalette);
iis.reset();
colorModel = new IndexColorModel(metadata.bitsPerPixel, 256, largePalette, 0, false);
sampleModel = colorModel.createCompatibleSampleModel(width, height);
} else {
int msize = metadata.bitsPerPixel == 1 ? 2 : 16;
colorModel = new IndexColorModel(metadata.bitsPerPixel, msize, smallPalette, 0, false);
sampleModel = colorModel.createCompatibleSampleModel(width, height);
}
}
} else {
ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_sRGB);
int[] nBits = {8, 8, 8};
colorModel =
new ComponentColorModel(
cs, nBits, false, false, Transparency.OPAQUE, DataBuffer.TYPE_BYTE);
sampleModel =
new ComponentSampleModel(
DataBuffer.TYPE_BYTE,
width,
height,
1,
width * colorPlanes,
new int[] {0, width, width * 2});
}
originalSampleModel = sampleModel;
originalColorModel = colorModel;
gotHeader = true;
}
