public static void RgbToGray(
RGB source, RGB dest, GrayscaleStyle style)
{
byte gray = 127;
switch (style)
{
case GrayscaleStyle.BT907:
gray = GetGray(source, BT907);
break;
case GrayscaleStyle.RMY:
gray = GetGray(source, RMY);
break;
case GrayscaleStyle.Y:
gray = GetGray(source, Y);
break;
}
dest.R = dest.G = dest.B = gray;
}
public static void HslToRgb(HSL hsl, RGB rgb)
{
if (hsl.Saturation == 0)
{
rgb.R = rgb.G = rgb.B = (byte)(hsl.Luminance * 255);
}
else
{
double v1, v2;
double hue = (double)hsl.Hue / 360;
v2 = (hsl.Luminance < 0.5) ?
(hsl.Luminance * (1 + hsl.Saturation)) :
((hsl.Luminance + hsl.Saturation) - (hsl.Luminance * hsl.Saturation));
v1 = 2 * hsl.Luminance - v2;
rgb.R = (byte)(255 * HueToRGB(v1, v2, hue + (1.0 / 3)));
rgb.G = (byte)(255 * HueToRGB(v1, v2, hue));
rgb.B = (byte)(255 * HueToRGB(v1, v2, hue - (1.0 / 3)));
}
}
public static HSL RgbToHsl(RGB rgb)
{
HSL hsl = new HSL();
RgbToHsl(rgb, hsl);
return hsl;
}
public static void RgbToGray(RGB source, RGB dest)
{
RgbToGray(source, dest, GrayscaleStyle.BT907);
}
public static RGB RgbToGray(RGB source, GrayscaleStyle style)
{
RGB dest = new RGB();
RgbToGray(source, dest, style);
return dest;
}
public static RGB RgbToGray(RGB source)
{
RGB dest = new RGB();
RgbToGray(source, dest);
return dest;
}
public static RGB HslToRgb(HSL hsl)
{
RGB rgb = new RGB();
HslToRgb(hsl, rgb);
return rgb;
}
private static byte GetGray(RGB rgb, int[] coefficient)
{
return (byte)((rgb.R * coefficient[0] +
rgb.G * coefficient[1] +
rgb.B * coefficient[2]) / coefficient[3]);
}
public static void RgbToHsl(RGB rgb, HSL hsl)
{
double r = (rgb.R / 255.0);
double g = (rgb.G / 255.0);
double b = (rgb.G / 255.0);
double min = Math.Min(Math.Min(r, g), b);
double max = Math.Max(Math.Max(r, g), b);
double delta = max - min;
hsl.Luminance = (max + min) / 2;
if (delta == 0)
{
hsl.Hue = 0;
hsl.Saturation = 0.0;
}
else
{
hsl.Saturation = (hsl.Luminance < 0.5) ?
(delta / (max + min)) : (delta / (2 - max - min));
double del_r = (((max - r) / 6) + (delta / 2)) / delta;
double del_g = (((max - g) / 6) + (delta / 2)) / delta;
double del_b = (((max - b) / 6) + (delta / 2)) / delta;
double hue;
if (r == max)
{
hue = del_b - del_g;
}
else if (g == max)
{
hue = (1.0 / 3) + del_r - del_b;
}
else
{
hue = (2.0 / 3) + del_g - del_r;
}
if (hue < 0)
{
hue += 1;
}
if (hue > 1)
{
hue -= 1;
}
hsl.Hue = (int)(hue * 360);
}
}