Simple libtiff Example
First, you have to install libtiff. On Linux it’s almost certainly in your repository you should install a package with an name similar to libtiff-dev.
On MacOS X I did the following:
curl ftp://ftp.remotesensing.org/pub/libtiff/tiff-3.9.5.zip > tiff-3.9.5.zip tar xvzf tiff-3.9.5.zip cd tiff-3.9.5 ./configure make sudo make install
Then create the following cpp file:
#include "tiffio.h"
#include <iostream>
using namespace std;
main(int argc, char* argv[])
{
TIFF* tif = TIFFOpen(argv[1], "r");
if (tif) {
uint32 w, h;
size_t npixels;
uint32* raster;
TIFFGetField(tif, TIFFTAG_IMAGEWIDTH, &w);
TIFFGetField(tif, TIFFTAG_IMAGELENGTH, &h);
npixels = w * h;
raster = (uint32*) _TIFFmalloc(npixels * sizeof (uint32));
if (raster != NULL) {
if (TIFFReadRGBAImage(tif, w, h, raster, 0)) {
cout << "P2" << endl;
cout << w << " " << h << endl;
cout << 255 << endl;
for(size_t c_h=0;c_h<h;c_h++) {
for(size_t c_w=0;c_w<w;c_w++) {
cout << raster[(w*h)-((c_h*w)+(w-c_w))]%256 << " ";
}
cout << endl;
}
}
_TIFFfree(raster);
}
TIFFClose(tif);
}
}
[/sourcecode]
This program converts a tiff file to a PGM (portable grey map) file. PGM is a simple text based format, this makes it very easy to debug. You can read more about PGM on <a href="http://en.wikipedia.org/wiki/Portable_graymap">wikipedia</a>.
Note: It's not converting the RGB value to grey very well it's simply modding the value for the example.
Compile the program as follow (on MacOS you'll need to have install XCode or another gcc version):
[sourcecode language="bash"]
g++ tiffsimple.cpp -ltiff
Then run it as:
./a.out inputfile.tif
You can view the resulting PGM file with ImageMagick.
Notes
You can also transform the TIFF coordinates rather than performing the transformation yourself when converting to PGM as follows:
#include “tiffio.h”
#include
using namespace std;
main(int argc, char* argv[])
{
TIFF* tif = TIFFOpen(argv[1], “r”);
if (tif) {
uint32 w, h;
size_t npixels;
uint32* raster;
TIFFGetField(tif, TIFFTAG_IMAGEWIDTH, &w);
TIFFGetField(tif, TIFFTAG_IMAGELENGTH, &h);
npixels = w * h;
raster = (uint32*) _TIFFmalloc(npixels * sizeof (uint32));
if (raster != NULL) {
if (TIFFReadRGBAImageOriented(tif, w, h, raster,ORIENTATION_TOPLEFT, 0)) {
cout << "P2" << endl;
cout << w << " " << h << endl;
cout << 255 << endl;
for(size_t c_h=0;c_h
RSS