152 lines
3.0 KiB
C
Executable File
152 lines
3.0 KiB
C
Executable File
typedef struct {
|
|
double r; // a fraction between 0 and 1
|
|
double g; // a fraction between 0 and 1
|
|
double b; // a fraction between 0 and 1
|
|
} rgb;
|
|
|
|
typedef struct {
|
|
double h; // angle in degrees
|
|
double s; // a fraction between 0 and 1
|
|
double v; // a fraction between 0 and 1
|
|
} hsv;
|
|
|
|
static rgb int2rgb(uint32_t in);
|
|
static hsv rgb2hsv(rgb in);
|
|
static rgb hsv2rgb(hsv in);
|
|
|
|
rgb int2rgb(uint32_t in)
|
|
{
|
|
rgb out;
|
|
out.r = (in >> 16) & 255;
|
|
out.g = (in >> 8) & 255;
|
|
out.b = in & 255;
|
|
return out;
|
|
}
|
|
|
|
hsv rgb2hsv(rgb in)
|
|
{
|
|
hsv out;
|
|
double min, max, delta;
|
|
|
|
min = in.r < in.g ? in.r : in.g;
|
|
min = min < in.b ? min : in.b;
|
|
|
|
max = in.r > in.g ? in.r : in.g;
|
|
max = max > in.b ? max : in.b;
|
|
|
|
out.v = max;
|
|
delta = max - min;
|
|
|
|
if (delta < 0.00001)
|
|
{
|
|
out.s = 0;
|
|
out.h = 0;
|
|
return out;
|
|
}
|
|
if(max > 0.0)
|
|
{
|
|
out.s = (delta / max);
|
|
}
|
|
else
|
|
{
|
|
out.s = 0.0;
|
|
out.h = 0;
|
|
return out;
|
|
}
|
|
|
|
if(in.r >= max)
|
|
out.h = ( in.g - in.b ) / delta;
|
|
else if(in.g >= max)
|
|
out.h = 2.0 + ( in.b - in.r ) / delta;
|
|
else
|
|
out.h = 4.0 + ( in.r - in.g ) / delta;
|
|
|
|
out.h *= 60.0;
|
|
|
|
if(out.h < 0.0)
|
|
out.h += 360.0;
|
|
|
|
return out;
|
|
}
|
|
|
|
|
|
rgb hsv2rgb(hsv in)
|
|
{
|
|
double hh, p, q, t, ff;
|
|
long i;
|
|
rgb out;
|
|
|
|
if(in.s <= 0.0)
|
|
{
|
|
out.r = in.v;
|
|
out.g = in.v;
|
|
out.b = in.v;
|
|
return out;
|
|
}
|
|
hh = in.h;
|
|
|
|
if(hh >= 360.0)
|
|
hh = 0.0;
|
|
|
|
hh /= 60.0;
|
|
i = (long)hh;
|
|
ff = hh - i;
|
|
p = in.v * (1.0 - in.s);
|
|
q = in.v * (1.0 - (in.s * ff));
|
|
t = in.v * (1.0 - (in.s * (1.0 - ff)));
|
|
|
|
switch(i)
|
|
{
|
|
case 0:
|
|
out.r = in.v;
|
|
out.g = t;
|
|
out.b = p;
|
|
break;
|
|
case 1:
|
|
out.r = q;
|
|
out.g = in.v;
|
|
out.b = p;
|
|
break;
|
|
case 2:
|
|
out.r = p;
|
|
out.g = in.v;
|
|
out.b = t;
|
|
break;
|
|
|
|
case 3:
|
|
out.r = p;
|
|
out.g = q;
|
|
out.b = in.v;
|
|
break;
|
|
case 4:
|
|
out.r = t;
|
|
out.g = p;
|
|
out.b = in.v;
|
|
break;
|
|
case 5:
|
|
default:
|
|
out.r = in.v;
|
|
out.g = p;
|
|
out.b = q;
|
|
break;
|
|
}
|
|
return out;
|
|
}
|
|
|
|
rgb gradient(rgb start, rgb end, double ratio)
|
|
{
|
|
if(ratio < 0)
|
|
ratio = 0;
|
|
if(ratio > 1)
|
|
ratio = 1;
|
|
|
|
auto start_hsv = rgb2hsv(start);
|
|
auto end_hsv = rgb2hsv(end);
|
|
|
|
hsv result;
|
|
result.h = start_hsv.h + ratio * (end_hsv.h - start_hsv.h);
|
|
result.s = start_hsv.s + ratio * (end_hsv.s - start_hsv.s);
|
|
result.v = start_hsv.v + ratio * (end_hsv.v - start_hsv.v);
|
|
|
|
return hsv2rgb(result);
|
|
} |