2005.08.04 20:02 "[Tiff] NEWBIE HELP NEEDED: Efficiently changing orientation tags in multipage tiff files", by Bradley Feldman
Hi all:
I'm new to this library and this list and looking for some helpful tips on
writing a routine to quickly and efficiently change the orientation tag of
every page of a multipage file.
I see plenty of examples with single page files, but nothing with
multipagers.
As a primer, I've experimented with tiffset but found it only effects the
first page of a multitiff file.
Likewise, I've written a program that is basically simple loop that reads a
tiff file's directories, sets the orientation tag and writes out the
directory to a new file, but I'm not getting any image data. How so do I
get the whole input file, page by page with just the orientation changed to
the output file? I'm obviously missing some steps
Here's some pseudo code I'm using:
infile = TIFFOpen("input.tif", "r");
outfile = TIFFOpen("output.tif", "w");
do {
TIFFGetFieldDefaulted(infile, TIFFTAG_ORIENTATION, &orientation);
orientation = newValue;
TIFFSetField(infile, TIFFTAG_ORIENTATION, orientation);
if (!TIFFWriteDirectory(outfile)) {
printf("Error!");
(void) TIFFClose(outfile);
(void) TIFFClose(infile);
exit (-2);
}
} while(TIFFReadDirectory(infile));
TIFFClose(infile);
TIFFClose(outfile);
Many thanks in advance for any help you can provide me with!
*Bradley