7 void hsl_to_rgb(float hsl_x, float hsl_y, float hsl_z, float *rgb_x, float *rgb_y, float *rgb_z)
9 float mi, ma, maminusmi, h;
12 maminusmi = hsl_y * 2 * hsl_z;
14 maminusmi = hsl_y * (2 - 2 * hsl_z);
16 // hsl_z = 0.5 * mi + 0.5 * ma
17 // maminusmi = - mi + ma
18 mi = hsl_z - 0.5 * maminusmi;
19 ma = hsl_z + 0.5 * maminusmi;
21 h = hsl_x - 6 * floor(hsl_x / 6);
23 //else if(ma == rgb_x)
24 // h = 60 * (rgb_y - rgb_z) / (ma - mi);
28 *rgb_y = h * (ma - mi) + mi;
31 //else if(ma == rgb_y)
32 // h = 60 * (rgb_z - rgb_x) / (ma - mi) + 120;
35 *rgb_x = (2 - h) * (ma - mi) + mi;
43 *rgb_z = (h - 2) * (ma - mi) + mi;
45 //else // if(ma == rgb_z)
46 // h = 60 * (rgb_x - rgb_y) / (ma - mi) + 240;
50 *rgb_y = (4 - h) * (ma - mi) + mi;
55 *rgb_x = (h - 4) * (ma - mi) + mi;
59 //else if(ma == rgb_x)
60 // h = 60 * (rgb_y - rgb_z) / (ma - mi);
65 *rgb_z = (6 - h) * (ma - mi) + mi;
69 void hslimage_color(float v_x, float v_y, float margin_x, float margin_y, float *rgb_x, float *rgb_y, float *rgb_z)
71 v_x = (v_x - margin_x) / (1 - 2 * margin_x);
72 v_y = (v_y - margin_y) / (1 - 2 * margin_y);
77 if(v_y > 0.875) // grey bar
78 hsl_to_rgb(0, 0, v_x, rgb_x, rgb_y, rgb_z);
80 hsl_to_rgb(v_x * 6, 1, (v_y / 0.875), rgb_x, rgb_y, rgb_z);
88 for(y = 0; y < 512; ++y)
90 for(x = 0; x < 512; ++x)
92 hslimage_color(x / 512.0, y / 512.0, MARGIN_X, MARGIN_Y, &r, &g, &b);
94 putc(floor(r * 15 + 0.5) * 17, stdout);
95 putc(floor(g * 15 + 0.5) * 17, stdout);
96 putc(floor(b * 15 + 0.5) * 17, stdout);
98 putc(floor(r * 255 + 0.5), stdout);
99 putc(floor(g * 255 + 0.5), stdout);
100 putc(floor(b * 255 + 0.5), stdout);