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2009.06.14 23:11 "Re: Tiff 16 bit and 32 bit images", by Keshab Neupane
Hi All,
Can you please look at my code and check what am I doing wrong.
I have to copy data from tiff 16 bit image into buffer and then into
destination buffer.
/* tiffinfo gives
TIFF Directory at offset 0x8 (8)
Image Width: 2160 Image Length: 900
Bits/Sample: 16
Sample Format: unsigned integer
Compression Scheme: None
Photometric Interpretation: min-is-black
Samples/Pixel: 1
Rows/Strip: 1
*/
#include <stdio.h>
#include "tiffio.h"
#include <stdlib.h>
int main(int argc , char **argv){
TIFF *tif;
uint16 bps, spp, bpp, photo, sampleFormat;
uint32 width, height;
char *buffer;
char *filename = argv[1];
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, &width);
TIFFGetField(tif, TIFFTAG_BITSPERSAMPLE, &bps);
TIFFGetField(tif, TIFFTAG_SAMPLESPERPIXEL, &spp);
bpp = bps * spp;
TIFFGetField(tif, TIFFTAG_PHOTOMETRIC, &photo);
TIFFGetField(tif, TIFFTAG_SAMPLEFORMAT, &sampleFormat);
int linesize = TIFFScanlineSize(tif);
buffer = (char*)malloc(linesize * height);
for (unsigned int i = 0; i < height; i++)
TIFFReadScanline(tif, &buffer[i * linesize], i, 0);
printf("sample format is %u\n",sampleFormat);
printf("photometric interpretation is %u\n",photo);
char *destination;
if(sampleFormat == 1){ // Check for unsigned integer case
// This is where I am doing wrong
for(unsigned int i =0; i < height/2; i++){
*((uint16*)destination)= ((uint16*)buffer)[i]; // copy data from
buffer to destination
// reason why I am casting with uint16 is because sample
format(image data) are unsigned interger values
buffer += 2;
destination += 2;
}
TIFFClose(tif);
free(buffer);
return 0;
}
My confusion/question,
What am I doing wrong while copying data from buffer to destination ?
I know I am doing wrong, but can't figure out how and why ?
Here, photometric interpretation is min-is-black, what will happen if I have
RGB or greyscale image i.e how do I copy data from buffer to destination ?
Sometimes, SAMPLEFORMAT is not given/available, how I can decide what data
types are tiff image made from. I need to handle 16 bit signed/unsigned and
32 bit float values !!
Any nice books where I can read all about tiff image format ? What are the
possible tiff image formats available/theoretically possible ?
I googled it but couldn't find any satisfactory result ?
Thank you everyone and sorry for asking so many questions,
Keshab