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2003.03.19 09:59 "Re: Grayscale 16-bit images", by Andrey Kiselev
On Tue, Mar 18, 2003 at 11:58:33PM +0100, Claus Ekstroem wrote:
> I'm trying to read a 16-bit grayscale image:
> I figure reading
> the file as a RGBAImage is the wrong approach, so could someone mail me a
> couple of lines of code to read and access the
> individual pixels?
You should use something like:
TIFF *tif;
uint16 spp, bpp, photo;
uint32 width, height;
char *buf;
tif = TIFFOpen(filename, "r");
if (!tif)
{
fprintf (stderr, "Can't open %s for reading\n", filename);
return 2;
}
TIFFGetField(tif, TIFFTAG_IMAGELENGTH, &height);
TIFFGetField(tif, TIFFTAG_IMAGEWIDTH, &height);
TIFFGetField(tif, TIFFTAG_BITSPERSAMPLE, &bpp);
TIFFGetField(tif, TIFFTAG_SAMPLESPERPIXEL, &spp);
TIFFGetField(tif, TIFFTAG_PHOTOMETRIC, &photo);
linesize = TIFFScanlineSize(tif);
buf = malloc(linesize * height);
for (i = 0; i < height; i++)
TIFFReadScanline(tif, &buf[i * linesize], i, 0);
TIFFClose(tif);
The whole image will be read into buffer. After this you can access
individual pixels according bpp and spp values,
i.e. for 16 bit unsigned integer: ((uint16 *)buf)[i].
Regards,
Andrey
--
Andrey V. Kiselev
Home phone: +7 812 5274898 ICQ# 26871517