169 lines
3.7 KiB
C
169 lines
3.7 KiB
C
/*
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* FloatImg library
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* HUE - SATURATION - VALUE
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+---------------------------------------------+
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| ce code ne fonctionne vraiment PAS ! |
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+---------------------------------------------+
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <string.h>
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#include <math.h>
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#include "../floatimg.h"
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extern int verbosity;
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/*
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https://baillehachepascal.dev/2021/rgb_hsv.php
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*/
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/* --------------------------------------------------------------------- */
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/* helper functions */
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static float maxi3f(float a, float b, float c)
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{
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return ((a > b)? (a > c ? a : c) : (b > c ? b : c));
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}
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static float mini3f(float a, float b, float c)
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{
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return ((a < b)? (a < c ? a : c) : (b < c ? b : c));
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}
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static int pseudoeq(float a, float b)
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{
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return (fabsf(a-b)<0.00000001); // UGLY HACK ???
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}
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/* --------------------------------------------------------------------- */
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/*
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* WARNING : ALL THIS CODE IS STRANGE
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*
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www.tutorialspoint.com/c-program-to-change-rgb-color-model-to-hsv-color-model
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*/
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int fimg_rgb2hsv(float rgb[3], float hsv[3], float scale)
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{
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// float h, s, v;
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float cmin, cmax, diff;
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// scale input value to [0..1]
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rgb[0] /= scale; rgb[1] /= scale; rgb[2] /= scale;
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hsv[0] = hsv[1] = hsv[2] = -12345.6789;
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cmin = mini3f(rgb[0], rgb[1], rgb[2]);
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cmax = maxi3f(rgb[0], rgb[1], rgb[2]);
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diff = cmax - cmin;
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if (pseudoeq(cmax, cmin)) hsv[0] = 0.0;
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else if (pseudoeq(cmax, rgb[0]))
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hsv[0] = fmod((60 * ((rgb[1] - rgb[2]) / diff) + 360), 360.0);
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else if (pseudoeq(cmax, rgb[1]))
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hsv[0] = fmod((60 * ((rgb[2] - rgb[0]) / diff) + 120), 360.0);
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else if (pseudoeq(cmax, rgb[2]))
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hsv[0] = fmod((60 * ((rgb[0] - rgb[1]) / diff) + 240), 360.0);
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if (pseudoeq(cmax, 0.0)) hsv[1] = 0.0;
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else hsv[1] = (diff / cmax) / 100.0;
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hsv[2] = cmax * 100.0; /* WHAT THE FUCK ? */
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#if DEBUG_LEVEL
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fprintf(stderr, "cmin/cmax %f %f\n", cmin, cmax);
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#endif
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return 0;
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}
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/* --------------------------------------------------------------------- */
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int fimg_hsv2rgb(float hsv[3], float rgb[3], float scale)
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{
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float hh, ff, p, q, t;
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long i;
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if(hsv[1] <= 0.0) { // < is bogus, just shuts up warnings
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rgb[0] = rgb[1] = rgb[2] = hsv[2];
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return 0;
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}
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hh = hsv[0];
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if(hh >= 360.0) hh = 0.0;
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hh /= 60.0;
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i = (long)hh;
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ff = hh - i;
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p = hsv[2] * (1.0 - hsv[1]);
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q = hsv[2] * (1.0 - (hsv[1] * ff));
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t = hsv[2] * (1.0 - (hsv[1] * (1.0 - ff)));
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switch(i) {
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case 0:
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rgb[0] = hsv[2]; rgb[1] = t; rgb[2] = p;
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break;
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case 1:
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rgb[0] = q; rgb[1] = hsv[2]; rgb[2] = p;
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break;
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case 2:
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rgb[0] = p; rgb[1] = hsv[2]; rgb[2] = t;
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break;
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case 3:
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rgb[0] = p; rgb[1] = q; rgb[2] = hsv[2];
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break;
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case 4:
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rgb[0] = t; rgb[1] = p; rgb[2] = hsv[2];
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break;
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case 5:
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default:
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rgb[0] = hsv[2]; rgb[1] = p; rgb[2] = q;
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break;
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}
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return 0;
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}
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/* --------------------------------------------------------------------- */
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/*
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* expect garbage !
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*/
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int fimg_essai_hsv(char *fname)
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{
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float colors[3], values[3], newcols[3];
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int foo, r, g, b;
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#define INC 16
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for (r=0; r<255; r+=INC) {
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for (g=0; g<255; g+=INC) {
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for (b=0; b<255; b+=INC) {
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printf("%4d %4d %4d ", r, g, b);
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colors[0] = (float)r;
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colors[1] = (float)g;
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colors[2] = (float)b;
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foo = fimg_rgb2hsv(colors, values, 255.0);
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if (foo) {
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fprintf(stderr, "%s: err %d in rgv->hsv\n", __func__, foo);
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exit(1);
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}
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printf(" %8.4f %8.4f %8.4f ",
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values[0], values[1], values[2]);
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foo = fimg_hsv2rgb(values, newcols, 255.0);
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if (foo) {
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fprintf(stderr, "%s: err %d in hsv->rgb\n", __func__, foo);
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exit(1);
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}
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printf(" %8.4f %8.4f %8.4f\n",
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newcols[0], newcols[1], newcols[2]);
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}
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}
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}
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return -1;
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}
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/* --------------------------------------------------------------------- */
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