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make hsv reversible 

SVN revision: 12821
This commit is contained in:
Carsten Haitzler 2005-01-08 07:55:42 +00:00
parent 7227d27988
commit 054f56166a
1 changed files with 99 additions and 100 deletions
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199
src/lib/color_helpers.c
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@ -5,115 +5,114 @@
*/
void
__imlib_rgb_to_hsv(int r, int g, int b, float *hue, float *saturation,
float *value)
__imlib_rgb_to_hsv(int r, int g, int b, float *h, float *s, float *v)
{
int f;
float i, j, k, max, min, d;
i = ((float)r) / 255.0;
j = ((float)g) / 255.0;
k = ((float)b) / 255.0;
f = 0;
max = min = i;
if (j > max)
{
max = j;
f = 1;
}
else
min = j;
if (k > max)
{
max = k;
f = 2;
}
else if (k < min)
min = k;
d = max - min;
*value = max;
if (max != 0)
*saturation = d / max;
else
*saturation = 0;
if (*saturation == 0)
*hue = 0;
int min, max;
int delta;
max = (r+g+abs(r-g))/2;
max = (max+b+abs(max-b))/2;
min = (r+g-abs(r-g))/2;
min = (min+b-abs(min-b))/2;
delta = max - min;
*v = (float)(100 * max) / 255.0;
if (max!=0)
*s = (float)(100 * delta) / (float)max;
else
{
switch (f)
{
case 0:
*hue = (j - k) / d;
break;
case 1:
*hue = 2 + (k - i) / d;
break;
case 2:
*hue = 4 + (i - j) / d;
break;
}
*hue *= 60.0;
if (*hue < 0)
*hue += 360.0;
*s = 0.0;
*h = 0.0;
*v = 0.0;
}
if (r == max)
{
*h = (float)(100*(g-b)) / (float)(6.0*delta);
}
else
{
if (g == max)
{
*h = (float)(100*(2*delta + b-r)) / (float)(6.0*delta);
}
else
{
*h = (float)(100*(4*delta+r-g)) / (float)(6.0*delta);
}
}
if (*h < 0.0) *h += 100.0;
if (*h > 100.0) *h -= 100.0;
}
void
__imlib_hsv_to_rgb(float hue, float saturation, float value, int *r, int *g,
int *b)
__imlib_hsv_to_rgb(float h, float s, float v, int *r, int *g, int *b)
{
int i, p, q, t, h;
float vs, vsf;
i = (int)(value * 255.0);
if (saturation == 0)
*r = *g = *b = i;
else
float hh, f;
float p, q, t;
int i;
if (s == 0.0)
{
if (hue == 360)
hue = 0;
hue = hue / 60.0;
h = (int)hue;
vs = value * saturation;
vsf = vs * (hue - h);
p = (int)(255.0 * (value - vs));
q = (int)(255.0 * (value - vsf));
t = (int)(255.0 * (value - vs + vsf));
switch (h)
{
case 0:
*r = i;
*g = t;
*b = p;
break;
case 1:
*r = q;
*g = i;
*b = p;
break;
case 2:
*r = p;
*g = i;
*b = t;
break;
case 3:
*r = p;
*g = q;
*b = i;
break;
case 4:
*r = t;
*g = p;
*b = i;
break;
case 5:
*r = i;
*g = p;
*b = q;
break;
}
*r = lround ((v*255.0)/100.0);
*g = lround ((v*255.0)/100.0);
*b = lround ((v*255.0)/100.0);
return;
}
hh = (h * 6.0) / 100.0;
i = floor (hh);
f = hh - (float)i;
p = v*(1.0 - s / 100.0) / 100.0;
q = v*(1.0 - (s*f) / 100.0) / 100.0;
t = v*(1.0 - s*(1.0 - f) / 100.0) / 100.0;
switch (i)
{
case 0:
{
*r = lround (v*255.0 / 100.0);
*g = lround (t*255.0);
*b = lround (p*255.0);
break;
}
case 1:
{
*r = lround (q*255.0);
*g = lround (v*255.0 / 100.0);
*b = lround (p*255.0);
break;
}
case 2:
{
*r = lround (p*255.0);
*g = lround (v*255.0 / 100.0);
*b = lround (t*255.0);
break;
}
case 3:
{
*r = lround (p*255.0);
*g = lround (q*255.0);
*b = lround (v*255.0 / 100.0);
break;
}
case 4:
{
*r = lround (t*255.0);
*g = lround (p*255.0);
*b = lround (v*255.0 / 100.0);
break;
}
case 5:
{
*r = lround (v*255.0 / 100.0);
*g = lround (p*255.0);
*b = lround (q*255.0);
break;
}
}
}