Bibliothèque de traitements d'images en virgule flottante. http://la.buvette.org/photos/cumul/
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/*
* FLOATIMG
* calculer un histogramme et l'afficher
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "../floatimg.h"
extern int verbosity;
/* --------------------------------------------------------------------- */
int fimg_calcul_histo(FloatImg *src, long *ghist, int sz)
{
float maxval;
int x, y, idx;
float rgb[3], moy;
fprintf(stderr, ">>> %s ( %p %p %d )\n", __func__, src, ghist, sz);
maxval = fimg_get_maxvalue(src);
fprintf(stderr, "maximum is %f\n", maxval);
for (y=0; y<src->height; y++) {
for(x=0; x<src->width; x++) {
fimg_get_rgb(src, x, y, rgb);
moy = (rgb[0]+rgb[1]+rgb[2]) / 3.0;
/* ok, here the had math part ... */
idx = (int)( (moy*sz) / maxval);
/* sanity check */
if (idx<0 || idx>=sz) {
fprintf(stderr, "idx = %d, error\n", idx);
abort();
}
ghist[idx]++;
}
}
return -66;
}
/* --------------------------------------------------------------------- */
#define NSLICES 999
int fimg_essai_histo(FloatImg *src, char *outpic, int k)
{
long histo[NSLICES];
int foo;
FILE *pipe;
fprintf(stderr, ">>> %s ( %p '%s' %d )\n", __func__, src, outpic, k);
memset(histo, 0, NSLICES*sizeof(long));
foo = fimg_calcul_histo(src, histo, NSLICES);
for (foo=0; foo<NSLICES; foo++) {
printf("%7d %ld\n", foo, histo[foo]);
}
pipe = popen("gnuplot", "w");
fprintf(pipe, "set term png size 1000,400\n");
fprintf(pipe, "set output \"histo.png\"\n");
fprintf(pipe, "plot 'toto' with lines\n");
fclose(pipe);
return -1;
}
/* --------------------------------------------------------------------- */