C/C++ : LibTiff Tutorial

C/C++ : LibTiff Tutorial

Libtiff is a library for reading and writing Tagged Image File Format (abbreviated TIFF) files. The set also contains command line tools for processing TIFFs. It is distributed in source code and can be found as binary builds for all kinds of platforms. The libtiff software was written by Sam Leffler while working for Silicon Graphics (wikipedia).

We can use this libtiff library in Windows and Linux (I am not yet try this libtiff library in other system operation like MAC). You can download the Windows version in this address : http://gnuwin32.sourceforge.net/packages/tiff.htm.

I am interested using this libtiff library to reading my tiff image and show the output in RGBA format. This is a simple code  how to print RGBA value from tiff image using libtiff library:

/*
 * readtiff.c
 *
 *  Created on: Jun 4, 2012
 *      Author: toto
 */

#include <stdio.h>
#include <tiffio.h>
#include <stdlib.h>

int main(int argc, char **argv)
{
	TIFF *image;
	uint32 width, height;
	int r1,c1, t1, imagesize;
	int nsamples;
	unsigned char *scanline=NULL;

	uint16 BitsPerSample;           // normally 8 for grayscale image
	uint16 SamplesPerPixel;         // normally 1 for grayscale image
	uint16 i;

	// Open the TIFF image
	if((image = TIFFOpen(argv[1], "r")) == NULL){
		fprintf(stderr, "Could not open incoming image\n");
		exit(42);
	}

	// Find the width and height of the image
	TIFFGetField(image, TIFFTAG_IMAGEWIDTH, &width);
	TIFFGetField(image, TIFFTAG_IMAGELENGTH, &height);
	TIFFGetField(image, TIFFTAG_BITSPERSAMPLE, &BitsPerSample);
	TIFFGetField(image, TIFFTAG_SAMPLESPERPIXEL, &SamplesPerPixel);
	imagesize = height * width + 1;	//get image size

	//allocate memory for reading tif image
	scanline = (unsigned char *)_TIFFmalloc(SamplesPerPixel*width);
	if (scanline == NULL){
		fprintf (stderr,"Could not allocate memory!\n");
		exit(0);
	}

	fprintf(stderr,"W=%i H=%i BitsPerSample=%i SamplesPerPixel=%i\n", width, height,BitsPerSample,SamplesPerPixel);
	for (r1 = 0; r1 < height; r1++)
	{
		TIFFReadScanline(image, scanline, r1, 0);
		for (c1 = 0; c1 < width; c1++)
		{
			t1 = c1*SamplesPerPixel;

			for(i=0; i<SamplesPerPixel; i++)
				printf("%u \t", *(scanline + t1+i));
			printf("\n");
		}
	}

	_TIFFfree(scanline); //free allocate memory

	TIFFClose(image);

}

Compile this C/C++ : LibTiff Tutorial with command :

gcc readtiff.c -ltiff -o readtiff

You can running this C/C++ : LibTiff Tutorial with command :

./readtiff sampletif.tiff > output.txt

We can plot see or plot this tiff RGBA value from the output.txt file.