private Color CalculateSelectedColor( Point p )
{
IColorSpaceStructure selectedColor = null;
if ( m_colorSpace is HsbColorSpace ) {
HSB hsb = ( HSB ) m_colorSpace.Structure;
if ( m_component == 'H' ) {
int brightness = ( int ) ( ( ( double ) 255 - p.Y ) / 2.55 );
int saturation = ( int ) ( ( double ) p.X / 2.55 );
selectedColor = new HSB( hsb.Hue, saturation, brightness );
} else if ( m_component == 'S' ) {
int hue = ( int ) ( p.X * ( ( double ) 360 / 255 ) );
int brightness = ( int ) ( ( ( double ) 255 - p.Y ) / 2.55 );
if ( hue == 360 ) {
hue = 0;
}
selectedColor = new HSB( hue, hsb.Saturation, brightness );
} else if ( m_component == 'B' ) {
int hue = ( int ) ( p.X * ( ( double ) 360 / 255 ) );
int saturation = ( int ) ( ( ( double ) 255 - p.Y ) / 2.55 );
if ( hue == 360 ) {
hue = 0;
}
selectedColor = new HSB( hue, saturation, hsb.Brightness );
}
} else if ( m_colorSpace is RgbColorSpace ) {
RGB rgb = ( RGB ) m_colorSpace.Structure;
if ( m_component == 'R' ) {
selectedColor = new RGB( rgb.Red, 255 - p.Y, p.X );
} else if ( m_component == 'G' ) {
selectedColor = new RGB( 255 - p.Y, rgb.Green, p.X );
} else if ( m_component == 'B' ) {
selectedColor = new RGB( p.X, 255 - p.Y, rgb.Blue);
}
}
RGB crgb;
HSB hsbSelectedColor;
if ( ( hsbSelectedColor = selectedColor as HSB ) != null ) {
crgb = ColorConverter.HsbToRgb( hsbSelectedColor );
} else {
crgb = ( RGB ) selectedColor;
}
return ColorConverter.RgbToColor( crgb );
}
/// <summary>
/// Converts a RGB color structure to a Color object.
/// </summary>
/// <param name="rgb">A RGB object representing the color that is to be
/// converted.</param>
/// <returns>A Color equivalent.</returns>
internal static Color RgbToColor( RGB rgb )
{
return Color.FromArgb( rgb.Red, rgb.Green, rgb.Blue );
}
/// <summary>
/// Converts RGB to HSB.
/// </summary>
/// <param name="rgb">A RGB object containing the RGB values that are to
/// be converted to HSB values.</param>
/// <returns>A HSB equivalent.</returns>
internal static HSB RgbToHsb( RGB rgb )
{
// NOTE #1: Even though we're dealing with a very small range of
// numbers, the accuracy of all calculations is fairly important.
// For this reason, I've opted to use double data types instead
// of float, which gives us a little bit extra precision (recall
// that precision is the number of significant digits with which
// the result is expressed).
double r = rgb.Red / 255d;
double g = rgb.Green / 255d;
double b = rgb.Blue / 255d;
double minValue = GetMinimumValue( r, g, b );
double maxValue = GetMaximumValue( r, g, b );
double delta = maxValue - minValue;
double hue = 0;
double saturation = 0;
double brightness = maxValue * 100;
if ( maxValue == 0 || delta == 0 ) {
hue = 0;
saturation = 0;
} else {
// NOTE #2: FXCop insists that we avoid testing for floating
// point equality (CA1902). Instead, we'll perform a series of
// tests with the help of Double.Epsilon that will provide
// a more accurate equality evaluation.
if ( minValue == 0 ) {
saturation = 100;
} else {
saturation = ( delta / maxValue ) * 100;
}
if ( Math.Abs( r - maxValue ) < Double.Epsilon ) {
hue = ( g - b) / delta;
} else if ( Math.Abs( g - maxValue ) < Double.Epsilon ) {
hue = 2 + ( b - r ) / delta;
} else if ( Math.Abs( b - maxValue ) < Double.Epsilon ) {
hue = 4 + ( r - g ) / delta;
}
}
hue *= 60;
if ( hue < 0 ) {
hue += 360;
}
return new HSB(
( int ) Math.Round( hue ),
( int ) Math.Round( saturation ),
( int ) Math.Round( brightness ) );
}
/// <summary>
/// Updates the color slider.
/// </summary>
private void UpdateColorSlider()
{
RGB rgb = ( RGB )this.rgbColorSpace.Structure;
HSB hsb = ( HSB )this.hsbColorSpace.Structure;
Rectangle region = new Rectangle(0, -1, 18, 257);
using (Graphics g = Graphics.FromImage(m_colorSliderBitmap)) {
if (this.m_currentColorSpace is RgbColorSpace)
{
char dChar = this.m_currentColorSpace.SelectedComponent.DisplayCharacter;
int red = rgb.Red;
int green = rgb.Green;
int blue = rgb.Blue;
Color startColor;
Color endColor;
switch (dChar)
{
case 'R':
startColor = Color.FromArgb(0, green, blue);
endColor = Color.FromArgb(255, green, blue);
break;
case 'G':
startColor = Color.FromArgb(red, 0, blue);
endColor = Color.FromArgb(red, 255, blue);
break;
default:
startColor = Color.FromArgb(red, green, 0);
endColor = Color.FromArgb(red, green, 255);
break;
}
using (LinearGradientBrush lgb = new LinearGradientBrush(region, startColor, endColor, 270f)) {
g.FillRectangle(lgb, region);
}
}
else if (this.m_currentColorSpace is HsbColorSpace)
{
if (this.m_currentColorSpace.SelectedComponent.DisplayCharacter == 'H')
{
Rectangle rect = new Rectangle(0, 0, 20, 256);
using (LinearGradientBrush brBrush = new LinearGradientBrush(rect, Color.Blue, Color.Red, 90f, false)) {
Color[] colorArray = { Color.Red, Color.Magenta, Color.Blue, Color.Cyan, Color.FromArgb(0, 255, 0), Color.Yellow, Color.Red };
float[] posArray = { 0.0f, 0.1667f, 0.3372f, 0.502f, 0.6686f, 0.8313f, 1.0f };
ColorBlend colorBlend = new ColorBlend();
colorBlend.Colors = colorArray;
colorBlend.Positions = posArray;
brBrush.InterpolationColors = colorBlend;
g.FillRectangle(brBrush, region);
}
}
else if (this.m_currentColorSpace.SelectedComponent.DisplayCharacter == 'B')
{
RGB sRgb = ColorConverter.HsbToRgb(new HSB(hsb.Hue, hsb.Saturation, 100));
RGB eRgb = ColorConverter.HsbToRgb(new HSB(hsb.Hue, hsb.Saturation, 0));
using (LinearGradientBrush lgb = new LinearGradientBrush(region, Color.FromArgb(sRgb.Red, sRgb.Green, sRgb.Blue), Color.FromArgb(eRgb.Red, eRgb.Green, eRgb.Blue), 90f)) {
g.FillRectangle(lgb, region);
}
}
else
{
RGB sRgb = ColorConverter.HsbToRgb(new HSB(hsb.Hue, 100, hsb.Brightness));
RGB eRgb = ColorConverter.HsbToRgb(new HSB(hsb.Hue, 0, hsb.Brightness));
using (LinearGradientBrush lgb = new LinearGradientBrush(region, Color.FromArgb(sRgb.Red, sRgb.Green, sRgb.Blue), Color.FromArgb(eRgb.Red, eRgb.Green, eRgb.Blue), 90f)) {
g.FillRectangle(lgb, region);
}
}
}
}
this.picColorSlider.Image = m_colorSliderBitmap;
}