/// <summary>
/// Converts RGB to HSV color.
/// </summary>
public static ColorHsv ToHsv(this Color rgb)
{
ColorHsv hsv = new ColorHsv();
float min, max, delta;
min = rgb.r < rgb.g ? rgb.r : rgb.g;
min = min < rgb.b ? min : rgb.b;
max = rgb.r > rgb.g ? rgb.r : rgb.g;
max = max > rgb.b ? max : rgb.b;
hsv.Value = max; // v
delta = max - min;
if (delta < 0.00001f)
{
hsv.Saturation = 0;
hsv.Hue = 0; // undefined, maybe nan?
return(hsv);
}
if (max > 0.0)
{ // NOTE: if Max is == 0, this divide would cause a crash
hsv.Saturation = (delta / max); // s
}
else
{
// if max is 0, then r = g = b = 0
// s = 0, h is undefined
hsv.Saturation = 0.0f;
hsv.Hue = float.NaN; // its now undefined
return(hsv);
}
if (rgb.r >= max) // > is bogus, just keeps compilor happy
{
hsv.Hue = (rgb.g - rgb.b) / delta; // between yellow & magenta
}
else if (rgb.g >= max)
{
hsv.Hue = 2.0f + (rgb.b - rgb.r) / delta; // between cyan & yellow
}
else
{
hsv.Hue = 4.0f + (rgb.r - rgb.g) / delta; // between magenta & cyan
}
hsv.Hue *= 60.0f; // degrees
if (hsv.Hue < 0.0f)
{
hsv.Hue += 360.0f;
}
return(hsv);
}
/// <summary>
/// Interpolates value for type.
/// </summary>
public static Color HsvInterpolator(Color from, Color to, float weight)
{
Color aRgb = from != null ? from : Color.black;
Color bRgb = to != null ? to : Color.black;
// convert colors to HSV
ColorHsv a = aRgb.ToHsv();
ColorHsv b = bRgb.ToHsv();
// interpolate values
ColorHsv resultHsv = new ColorHsv();
resultHsv.Hue = Lerp(a.Hue, b.Hue, weight);
resultHsv.Saturation = Lerp(a.Saturation, b.Saturation, weight);
resultHsv.Value = Lerp(a.Value, b.Value, weight);
// convert back to RGB
Color result = resultHsv.ToRgb();
result.a = Lerp(aRgb.a, bRgb.a, weight);
return(result);
}
/// <summary>
/// Converts HSV to RGB color.
/// </summary>
public static Color ToRgb(this ColorHsv hsv)
{
float hh, p, q, t, ff;
long i;
Color rgb = new Color();
if (hsv.Saturation <= 0.0f)
{
rgb.r = hsv.Value;
rgb.g = hsv.Value;
rgb.b = hsv.Value;
return(rgb);
}
hh = hsv.Hue;
if (hh >= 360.0f)
{
hh = 0.0f;
}
hh /= 60.0f;
i = (long)hh;
ff = hh - i;
p = hsv.Value * (1.0f - hsv.Saturation);
q = hsv.Value * (1.0f - (hsv.Saturation * ff));
t = hsv.Value * (1.0f - (hsv.Saturation * (1.0f - ff)));
switch (i)
{
case 0:
rgb.r = hsv.Value;
rgb.g = t;
rgb.b = p;
break;
case 1:
rgb.r = q;
rgb.g = hsv.Value;
rgb.b = p;
break;
case 2:
rgb.r = p;
rgb.g = hsv.Value;
rgb.b = t;
break;
case 3:
rgb.r = p;
rgb.g = q;
rgb.b = hsv.Value;
break;
case 4:
rgb.r = t;
rgb.g = p;
rgb.b = hsv.Value;
break;
case 5:
default:
rgb.r = hsv.Value;
rgb.g = p;
rgb.b = q;
break;
}
return(rgb);
}
