xonotic/misc/tools/hslimage.c
2010-03-18 14:22:15 +01:00

105 lines
2.1 KiB
C

#include <math.h>
#include <stdio.h>
#define MARGIN_X 0
#define MARGIN_Y 0
void hsl_to_rgb(float hsl_x, float hsl_y, float hsl_z, float *rgb_x, float *rgb_y, float *rgb_z)
{
float mi, ma, maminusmi, h;
if(hsl_z <= 0.5)
maminusmi = hsl_y * 2 * hsl_z;
else
maminusmi = hsl_y * (2 - 2 * hsl_z);
// hsl_z = 0.5 * mi + 0.5 * ma
// maminusmi = - mi + ma
mi = hsl_z - 0.5 * maminusmi;
ma = hsl_z + 0.5 * maminusmi;
h = hsl_x - 6 * floor(hsl_x / 6);
//else if(ma == rgb_x)
// h = 60 * (rgb_y - rgb_z) / (ma - mi);
if(h <= 1)
{
*rgb_x = ma;
*rgb_y = h * (ma - mi) + mi;
*rgb_z = mi;
}
//else if(ma == rgb_y)
// h = 60 * (rgb_z - rgb_x) / (ma - mi) + 120;
else if(h <= 2)
{
*rgb_x = (2 - h) * (ma - mi) + mi;
*rgb_y = ma;
*rgb_z = mi;
}
else if(h <= 3)
{
*rgb_x = mi;
*rgb_y = ma;
*rgb_z = (h - 2) * (ma - mi) + mi;
}
//else // if(ma == rgb_z)
// h = 60 * (rgb_x - rgb_y) / (ma - mi) + 240;
else if(h <= 4)
{
*rgb_x = mi;
*rgb_y = (4 - h) * (ma - mi) + mi;
*rgb_z = ma;
}
else if(h <= 5)
{
*rgb_x = (h - 4) * (ma - mi) + mi;
*rgb_y = mi;
*rgb_z = ma;
}
//else if(ma == rgb_x)
// h = 60 * (rgb_y - rgb_z) / (ma - mi);
else // if(h <= 6)
{
*rgb_x = ma;
*rgb_y = mi;
*rgb_z = (6 - h) * (ma - mi) + mi;
}
}
void hslimage_color(float v_x, float v_y, float margin_x, float margin_y, float *rgb_x, float *rgb_y, float *rgb_z)
{
v_x = (v_x - margin_x) / (1 - 2 * margin_x);
v_y = (v_y - margin_y) / (1 - 2 * margin_y);
if(v_x < 0) v_x = 0;
if(v_y < 0) v_y = 0;
if(v_x > 1) v_x = 1;
if(v_y > 1) v_y = 1;
if(v_y > 0.875) // grey bar
hsl_to_rgb(0, 0, v_x, rgb_x, rgb_y, rgb_z);
else
hsl_to_rgb(v_x * 6, 1, (v_y / 0.875), rgb_x, rgb_y, rgb_z);
}
int main()
{
int x, y;
float r, g, b;
for(y = 0; y < 512; ++y)
{
for(x = 0; x < 512; ++x)
{
hslimage_color(x / 512.0, y / 512.0, MARGIN_X, MARGIN_Y, &r, &g, &b);
/*
putc(floor(r * 15 + 0.5) * 17, stdout);
putc(floor(g * 15 + 0.5) * 17, stdout);
putc(floor(b * 15 + 0.5) * 17, stdout);
*/
putc(floor(r * 255 + 0.5), stdout);
putc(floor(g * 255 + 0.5), stdout);
putc(floor(b * 255 + 0.5), stdout);
}
}
return 0;
}