/// <summary>
/// Convert from HSL to RGB color space.
/// </summary>
///
/// <param name="hsl">Source color in <b>HSL</b> color space.</param>
/// <param name="rgb">Destination color in <b>RGB</b> color space.</param>
///
public static void ToRGB(HSL hsl, RGB rgb)
{
if (hsl.Saturation == 0)
{
// gray values
rgb.Red = rgb.Green = rgb.Blue = (byte)(hsl.Luminance * 255);
}
else
{
float v1, v2;
float hue = (float)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.Red = (byte)(255 * Hue_2_RGB(v1, v2, hue + (1.0f / 3)));
rgb.Green = (byte)(255 * Hue_2_RGB(v1, v2, hue));
rgb.Blue = (byte)(255 * Hue_2_RGB(v1, v2, hue - (1.0f / 3)));
}
rgb.Alpha = 255;
}
// Gather statistics for the specified image
private unsafe void ProcessImage(UnmanagedImage image, byte *mask, int maskLineSize)
{
// get image dimension
int width = image.Width;
int height = image.Height;
pixels = pixelsWithoutBlack = 0;
int[] s = new int[256];
int[] l = new int[256];
int[] swb = new int[256];
int[] lwb = new int[256];
RGB rgb = new RGB( );
HSL hsl = new HSL( );
int pixelSize = (image.PixelFormat == PixelFormat.Format24bppRgb) ? 3 : 4;
int offset = image.Stride - width * pixelSize;
int maskOffset = maskLineSize - width;
// do the job
byte *p = (byte *)image.ImageData.ToPointer( );
if (mask == null)
{
// for each line
for (int y = 0; y < height; y++)
{
// for each pixel
for (int x = 0; x < width; x++, p += pixelSize)
{
rgb.Red = p[RGB.R];
rgb.Green = p[RGB.G];
rgb.Blue = p[RGB.B];
// convert to HSL color space
AForgeCore.Imaging.HSL.FromRGB(rgb, hsl);
s[(int)(hsl.Saturation * 255)]++;
l[(int)(hsl.Luminance * 255)]++;
pixels++;
if (hsl.Luminance != 0.0)
{
swb[(int)(hsl.Saturation * 255)]++;
lwb[(int)(hsl.Luminance * 255)]++;
pixelsWithoutBlack++;
}
}
p += offset;
}
}
else
{
// for each line
for (int y = 0; y < height; y++)
{
// for each pixel
for (int x = 0; x < width; x++, p += pixelSize, mask++)
{
if (*mask == 0)
{
continue;
}
rgb.Red = p[RGB.R];
rgb.Green = p[RGB.G];
rgb.Blue = p[RGB.B];
// convert to HSL color space
AForgeCore.Imaging.HSL.FromRGB(rgb, hsl);
s[(int)(hsl.Saturation * 255)]++;
l[(int)(hsl.Luminance * 255)]++;
pixels++;
if (hsl.Luminance != 0.0)
{
swb[(int)(hsl.Saturation * 255)]++;
lwb[(int)(hsl.Luminance * 255)]++;
pixelsWithoutBlack++;
}
}
p += offset;
mask += maskOffset;
}
}
// create histograms
saturation = new ContinuousHistogram(s, new Range(0, 1));
luminance = new ContinuousHistogram(l, new Range(0, 1));
saturationWithoutBlack = new ContinuousHistogram(swb, new Range(0, 1));
luminanceWithoutBlack = new ContinuousHistogram(lwb, new Range(0, 1));
}