Bibliothèque de traitements d'images en virgule flottante. http://la.buvette.org/photos/cumul/
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FloatImg/lib/fimg-math.c

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4 years ago
/*
* fimg-core.c
*
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <math.h>
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#include "../floatimg.h"
extern int verbosity; /* must be declared around main() */
/* ---------------------------------------------------------------- */
float fimg_get_maxvalue(FloatImg *head)
{
float maxval;
int foo;
if (head->type != FIMG_TYPE_RGB && head->type != FIMG_TYPE_GRAY) {
fprintf(stderr, "%s : type %d invalide\n",
__func__, head->type);
return nanf("wtf ?");
}
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maxval = 0.0; /* no negative values allowed */
switch (head->type) {
case FIMG_TYPE_RGB:
for (foo=0; foo<(head->width*head->height); foo++) {
if (head->R[foo] > maxval) maxval = head->R[foo];
if (head->G[foo] > maxval) maxval = head->G[foo];
if (head->B[foo] > maxval) maxval = head->B[foo];
}
case FIMG_TYPE_GRAY:
for (foo=0; foo<(head->width*head->height); foo++) {
if (head->R[foo] > maxval) maxval = head->R[foo];
}
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}
return maxval;
}
/* ---------------------------------------------------------------- */
int fimg_meanvalues(FloatImg *head, float means[4])
{
int idx, surface;
surface = head->width * head->height;
if (surface < 1) return -1;
memset(means, 0, 4*sizeof(float));
for (idx=0; idx<surface; idx++) {
means[0] += head->R[idx];
if (head->type > 2) {
means[1] += head->G[idx];
means[2] += head->B[idx];
}
}
for (idx=0; idx<4; idx++) means[idx] /= (float)surface;
return 0;
}
/* ---------------------------------------------------------------- */
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/*
* more elaborate functions are in fimg-2gray.c
*/
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int fimg_to_gray(FloatImg *head)
{
float add;
int foo;
if (head->type != FIMG_TYPE_RGB) {
fprintf(stderr, "%s : type %d invalide\n",
__func__, head->type);
return -3;
}
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for (foo=0; foo<(head->width*head->height); foo++) {
add = head->R[foo];
add += head->G[foo];
add += head->B[foo];
head->R[foo] = head->G[foo] = head->B[foo] = add / 3.0;
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}
return -1;
}
/* ---------------------------------------------------------------- */
void fimg_add_cste(FloatImg *fi, float value)
{
int nbre, idx;
if (fi->type != FIMG_TYPE_RGB) {
fprintf(stderr, "%s : type %d invalide\n",
__func__, fi->type);
return;
}
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nbre = fi->width * fi->height * fi->type;
#if DEBUG_LEVEL
fprintf(stderr, "%s, nbre is %d\n", __func__, nbre);
#endif
for (idx=0; idx<nbre; idx++) {
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fi->R[idx] += value;
}
}
/* ---------------------------------------------------------------- */
int fimg_count_negativ(FloatImg *fi)
{
int nbre, idx;
int count;
if (fi->type != FIMG_TYPE_RGB) {
fprintf(stderr, "%s : type %d invalide\n",
__func__, fi->type);
return -1;
}
nbre = fi->width * fi->height * fi->type;
count = 0;
for (idx=0; idx<nbre; idx++) {
if (fi->R[idx] < 0.0) count++;
}
return count;
}
/* ---------------------------------------------------------------- */
void fimg_mul_cste(FloatImg *fi, float value)
{
int nbre, idx;
if (fi->type != FIMG_TYPE_RGB) {
fprintf(stderr, "%s : type %d invalide\n",
__func__, fi->type);
return;
}
nbre = fi->width * fi->height * fi->type;
// #if DEBUG_LEVEL
fprintf(stderr, "%s, nbre is %d\n", __func__, nbre);
// #endif
for (idx=0; idx<nbre; idx++) {
fi->R[idx] *= value;
}
}
/* ---------------------------------------------------------------- */
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/* Warning: this function is _very_ slow */
void fimg_drand48(FloatImg *fi, float kmul)
{
int nbre, idx;
#if DEBUG_LEVEL
fprintf(stderr, ">>> %s ( %p %g )\n", __func__, fi, kmul);
#endif
if (fi->type != FIMG_TYPE_RGB) {
fprintf(stderr, "%s : type %d invalide\n",
__func__, fi->type);
return;
}
nbre = fi->width * fi->height;
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for (idx=0; idx<nbre; idx++) {
fi->R[idx] = drand48() * kmul;
fi->G[idx] = drand48() * kmul;
fi->B[idx] = drand48() * kmul;
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}
}
/* ---------------------------------------------------------------- */