/// <summary>
/// Convert RGB colorspace to HSI colorspace.
/// </summary>
public static VectorHsi RGB2HSI(VectorRgb rgb)
{
VectorHsi hsi = new VectorHsi();
//method from CxImageLib. ximadsp.cpp file.
byte H, S, I;
UInt16 Rdelta, Gdelta, Bdelta;
//get R, G, and B in 8-bit
byte R = rgb.R;
byte G = rgb.G;
byte B = rgb.B;
byte cMax = Math.Max(Math.Max(R, G), B);// calculate lightness (intensity)
byte cMin = Math.Min(Math.Min(R, G), B);
I = (byte)((((cMax + cMin) * HSIMAX) + RGBMAX) / (2 * RGBMAX));
if (cMax == cMin){ // r=g=b --> achromatic case
S = 0; // saturation
H = HSIUNDEFINED; // hue
}
else { // chromatic case
if (I <= (HSIMAX / 2)) // saturation
S = (byte)((((cMax - cMin) * HSIMAX) + ((cMax + cMin) / 2)) / (cMax + cMin));
else
S = (byte)((((cMax - cMin) * HSIMAX) + ((2 * RGBMAX - cMax - cMin) / 2)) / (2 * RGBMAX - cMax - cMin));
// hue
Rdelta = (UInt16)((((cMax - R) * (HSIMAX / 6)) + ((cMax - cMin) / 2)) / (cMax - cMin));
Gdelta = (UInt16)((((cMax - G) * (HSIMAX / 6)) + ((cMax - cMin) / 2)) / (cMax - cMin));
Bdelta = (UInt16)((((cMax - B) * (HSIMAX / 6)) + ((cMax - cMin) / 2)) / (cMax - cMin));
if (R == cMax)
H = (byte)(Bdelta - Gdelta);
else if (G == cMax)
H = (byte)((HSIMAX / 3) + Rdelta - Bdelta);
else // B == cMax
H = (byte)(((2 * HSIMAX) / 3) + Gdelta - Rdelta);
//if (H < 0) H += HSIMAX; //always false
if (H > HSIMAX) H -= HSIMAX;
}
hsi.H = (float)(H / 255.0f);
hsi.S = (float)(S / 255.0f);
hsi.I = (float)(I / 255.0f);
return hsi;
}
/// <summary>
/// show in TextBoxes HSI and RGB components
/// </summary>
/// <param name="color">color of pixel</param>
/// <param name="boxes">6 TextBoxes</param>
public static void ShowPixelComponents(Color color, params TextBox[] boxes)
{
VectorHsi hsi = new VectorHsi(color);
int h = (int)(hsi.H * 255f);
int s = (int)(hsi.S * 255f);
int i = (int)(hsi.I * 255f);
if (boxes.Length == 6)
{
boxes[0].Text = Convert.ToString(h);
boxes[1].Text = Convert.ToString(s);
boxes[2].Text = Convert.ToString(i);
boxes[3].Text = Convert.ToString(color.R);
boxes[4].Text = Convert.ToString(color.G);
boxes[5].Text = Convert.ToString(color.B);
}
}
/// <summary>
/// Convert HSI colorspace to RGB colorspace.
/// </summary>
public static VectorRgb HSI2RGB(VectorHsi hsi)
{
float h = hsi.H;
float s = hsi.S;
float i = hsi.I;
//method from CxImageLib. ximadsp.cpp file.
float m1, m2;
byte R, G, B;
h = (float)h * 360.0f;
if (i <= 0.5) m2 = i * (1 + s);
else m2 = i + s - i * s;
m1 = 2 * i - m2;
if (s == 0)
{
R = G = B = (byte)(i * 255.0f);
}
else
{
R = (byte)(HueToRGB(m1, m2, h + 120) * 255.0f);
G = (byte)(HueToRGB(m1, m2, h) * 255.0f);
B = (byte)(HueToRGB(m1, m2, h - 120) * 255.0f);
}
return new VectorRgb(R, G, B);
}
/// <summary>
/// Convert HSI colorspace to Color struct.
/// </summary>
public static Color HSI2COLOR(VectorHsi hsi)
{
float h = hsi.H;
float s = hsi.S;
float i = hsi.I;
float m1, m2;
byte R, G, B;
h = (float)h * 360.0f;
if (i <= 0.5) m2 = i * (1 + s);
else m2 = i + s - i * s;
m1 = 2 * i - m2;
if (s == 0)
{
R = G = B = (byte)(i * 255.0f);
}
else
{
R = (byte)(HueToRGB(m1, m2, h + 120) * 255.0f);
G = (byte)(HueToRGB(m1, m2, h) * 255.0f);
B = (byte)(HueToRGB(m1, m2, h - 120) * 255.0f);
}
return Color.FromArgb(R, G, B);
}
/// <summary>
/// Copy Constructor
/// </summary>
/// <param name="vec">Vector HSI</param>
public VectorHsi(VectorHsi vec)
{
this.h = vec.h;
this.s = vec.s;
this.i = vec.i;
}
/// <summary>
/// Clamp
/// </summary>
public static VectorHsi Clamp(VectorHsi source, float min, float max)
{
VectorHsi result = source;
if (result.h < min) result.h = min;
if (result.h > max) result.h = max;
if (result.s < min) result.s = min;
if (result.s > max) result.s = max;
if (result.i < min) result.i = min;
if (result.i > max) result.i = max;
return result;
}
/// <summary>
/// Constructor - transformation HSI to RGB
/// </summary>
/// <param name="vec">Vector HSI</param>
public VectorRgb(VectorHsi vec)
{
System.Drawing.Color cl = ColorspaceHelper.HSI2COLOR(vec);
this.r = cl.R;
this.g = cl.G;
this.b = cl.B;
}
/// <summary>
/// Filter processing.
/// </summary>
/// <param name="rOriginal">Original raster.</param>
/// <returns>Raster.</returns>
public override Raster ProcessWithoutWorker(Raster rOriginal)
{
int width = rOriginal.Width;
int height = rOriginal.Height;
Raster raster = new Raster(width, height);
VectorHsi hsi;
float fIntensity = (float)this.intensity / 255f;
float fSaturation = (float)this.saturation / 255f;
float fHue = (float)this.hue / 255f;
for (int j = 0; j < height; j++)
{
for (int i = 0; i < width; i++)
{
hsi = new VectorHsi(rOriginal[i, j]);
hsi.ChangeSaturation(fSaturation);
hsi.ChangeIntensity(fIntensity);
hsi.ChangeHue(fHue);
hsi = VectorHsi.Clamp(hsi, 0f, 1f);
raster[i, j] = hsi.ToVectorRGB();
}
}
return raster;
}
/// <summary>
/// Filter processing, with BackgroundWorker.
/// </summary>
/// <param name="rOriginal">Original raster.</param>
/// <param name="worker">BackgroundWorker.</param>
/// <returns>Raster.</returns>
public override Raster ProcessRaster(Raster rOriginal, System.ComponentModel.BackgroundWorker worker)
{
worker.WorkerReportsProgress = true;
int width = rOriginal.Width;
int height = rOriginal.Height;
Raster raster = new Raster(width, height);
VectorHsi hsi;
float fIntensity = (float)this.intensity / 255f;
float fSaturation = (float)this.saturation / 255f;
float fHue = (float)this.hue / 255f;
DateTime startTime = DateTime.Now;
for (int j = 0; j < height; j++)
{
for (int i = 0; i < width; i++)
{
hsi = new VectorHsi(rOriginal[i, j]);
hsi.ChangeSaturation(fSaturation);
hsi.ChangeIntensity(fIntensity);
hsi.ChangeHue(fHue);
hsi = VectorHsi.Clamp(hsi, 0.0f, 1.0f);
raster[i, j] = hsi.ToVectorRGB();
}
worker.ReportProgress((int)(100f * j / height), DateTime.Now - startTime);
}
return raster;
}
