/// <summary>
/// Convert an <see cref="HSBColor" /> value to an equivalent <see cref="Color" /> value.
/// </summary>
/// <remarks>
/// This method is based on code from http://www.cs.rit.edu/~ncs/color/ by Eugene Vishnevsky.
/// </remarks>
/// <param name="hsbColor">The <see cref="HSBColor" /> struct to be converted</param>
/// <returns>An equivalent <see cref="Color" /> struct, compatible with the GDI+ library</returns>
public static Color ToRGB(HSBColor hsbColor)
{
Color rgbColor = Color.Black;
// Determine which sector of the color wheel contains this hue
// hsbColor.H ranges from 0 to 255, and there are 6 sectors, so 42.5 per sector
int sector = (int)Math.Floor((double)hsbColor.H / 42.5);
// Calculate where the hue lies within the sector for interpolation purpose
double fraction = (double)hsbColor.H / 42.5 - (double)sector;
double sFrac = (double)hsbColor.S / 255.0;
byte p = (byte)(((double)hsbColor.B * (1.0 - sFrac)) + 0.5);
byte q = (byte)(((double)hsbColor.B * (1.0 - sFrac * fraction)) + 0.5);
byte t = (byte)(((double)hsbColor.B * (1.0 - sFrac * (1.0 - fraction))) + 0.5);
switch (sector)
{
case 0: // red - yellow
rgbColor = Color.FromArgb(hsbColor.A, hsbColor.B, t, p);
break;
case 1: // yellow - green
rgbColor = Color.FromArgb(hsbColor.A, q, hsbColor.B, p);
break;
case 2: // green - cyan
rgbColor = Color.FromArgb(hsbColor.A, p, hsbColor.B, t);
break;
case 3: // cyan - blue
rgbColor = Color.FromArgb(hsbColor.A, p, q, hsbColor.B);
break;
case 4: // blue - magenta
rgbColor = Color.FromArgb(hsbColor.A, t, p, hsbColor.B);
break;
case 5:
default: // magenta - red
rgbColor = Color.FromArgb(hsbColor.A, hsbColor.B, p, q);
break;
}
return rgbColor;
}
public Image TestChangeColor(Bitmap bmp, byte minHue,byte maxHue,byte newHue)
{
BitmapData bmpData = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height),
ImageLockMode.ReadWrite, bmp.PixelFormat);
IntPtr ptr = bmpData.Scan0;
int bytes = bmpData.Stride * bmpData.Height;
byte[] rgbValues = new byte[bytes];
System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues, 0, bytes);
for (int c = 0; c < rgbValues.Length; c += 4)
{
HSBColor hsb = new HSBColor(Color.FromArgb(
rgbValues[c + 3], rgbValues[c + 2],
rgbValues[c + 1], rgbValues[c]));
if (hsb.H >= minHue && hsb.H <= maxHue)
{
hsb.H = Convert.ToByte(newHue);
}
Color color = hsb.ToRGB();
rgbValues[c] = color.B;
rgbValues[c + 1] = color.G;
rgbValues[c + 2] = color.R;
rgbValues[c + 3] = color.A;
}
System.Runtime.InteropServices.Marshal.Copy(rgbValues, 0, ptr, bytes);
bmp.UnlockBits(bmpData);
return (Image)bmp;
}
/// <summary>
/// Convert a <see cref="Color" /> value to an equivalent <see cref="HSBColor" /> value.
/// </summary>
/// <remarks>
/// This method is based on code from http://www.cs.rit.edu/~ncs/color/ by Eugene Vishnevsky.
/// </remarks>
/// <param name="rgbColor">The <see cref="Color" /> struct to be converted</param>
/// <returns>An equivalent <see cref="HSBColor" /> struct</returns>
public static HSBColor FromRGB(Color rgbColor)
{
double r = (double)rgbColor.R / 255.0;
double g = (double)rgbColor.G / 255.0;
double b = (double)rgbColor.B / 255.0;
double min = Math.Min(Math.Min(r, g), b);
double max = Math.Max(Math.Max(r, g), b);
HSBColor hsbColor = new HSBColor(rgbColor.A, 0, 0, 0);
hsbColor.B = (byte)(max * 255.0 + 0.5);
double delta = max - min;
if (max != 0.0)
{
hsbColor.S = (byte)(delta / max * 255.0 + 0.5);
}
else
{
hsbColor.S = 0;
hsbColor.H = 0;
return hsbColor;
}
double h;
if (r == max)
h = (g - b) / delta; // between yellow & magenta
else if (g == max)
h = 2 + (b - r) / delta; // between cyan & yellow
else
h = 4 + (r - g) / delta; // between magenta & cyan
hsbColor.H = (byte)(h * 42.5);
if (hsbColor.H < 0)
hsbColor.H += 255;
return hsbColor;
}
