/// <summary>
/// Create a hue filter matrix using the given angle in degrees.
/// </summary>
/// <param name="degrees">The angle of rotation in degrees.</param>
/// <returns>The <see cref="Matrix4x4"/></returns>
public static Matrix4x4 CreateHueFilter(float degrees)
{
// Wrap the angle round at 360.
degrees %= 360;
// Make sure it's not negative.
while (degrees < 0)
{
degrees += 360;
}
float radian = MathFExtensions.DegreeToRadian(degrees);
float cosRadian = MathF.Cos(radian);
float sinRadian = MathF.Sin(radian);
// The matrix is set up to preserve the luminance of the image.
// See http://graficaobscura.com/matrix/index.html
// Number are taken from https://msdn.microsoft.com/en-us/library/jj192162(v=vs.85).aspx
return(new Matrix4x4
{
M11 = .213F + (cosRadian * .787F) - (sinRadian * .213F),
M12 = .213F - (cosRadian * .213F) - (sinRadian * 0.143F),
M13 = .213F - (cosRadian * .213F) - (sinRadian * .787F),
M21 = .715F - (cosRadian * .715F) - (sinRadian * .715F),
M22 = .715F + (cosRadian * .285F) + (sinRadian * 0.140F),
M23 = .715F - (cosRadian * .715F) + (sinRadian * .715F),
M31 = .072F - (cosRadian * .072F) + (sinRadian * .928F),
M32 = .072F - (cosRadian * .072F) - (sinRadian * 0.283F),
M33 = .072F + (cosRadian * .928F) + (sinRadian * .072F),
M44 = 1
});
}
public CieLuv Convert(CieLchuv input)
{
// Conversion algorithm described here:
// https://en.wikipedia.org/wiki/CIELUV#Cylindrical_representation_.28CIELCH.29
float l = input.L, c = input.C, hDegrees = input.H;
float hRadians = MathFExtensions.DegreeToRadian(hDegrees);
float u = c * MathF.Cos(hRadians);
float v = c * MathF.Sin(hRadians);
return(new CieLuv(l, u, v, input.WhitePoint));
}
public CieLab Convert(CieLch input)
{
// Conversion algorithm described here:
// https://en.wikipedia.org/wiki/Lab_color_space#Cylindrical_representation:_CIELCh_or_CIEHLC
float l = input.L, c = input.C, hDegrees = input.H;
float hRadians = MathFExtensions.DegreeToRadian(hDegrees);
float a = c * MathF.Cos(hRadians);
float b = c * MathF.Sin(hRadians);
return(new CieLab(l, a, b, input.WhitePoint));
}
/// <summary>
/// Initializes a new instance of the <see cref="HueProcessor{TPixel}"/> class.
/// </summary>
/// <param name="angle">The new brightness of the image. Must be between -100 and 100.</param>
public HueProcessor(float angle)
{
// Wrap the angle round at 360.
angle = angle % 360;
// Make sure it's not negative.
while (angle < 0)
{
angle += 360;
}
this.Angle = angle;
float radians = MathFExtensions.DegreeToRadian(angle);
float cosradians = MathF.Cos(radians);
float sinradians = MathF.Sin(radians);
float lumR = .213F;
float lumG = .715F;
float lumB = .072F;
float oneMinusLumR = 1 - lumR;
float oneMinusLumG = 1 - lumG;
float oneMinusLumB = 1 - lumB;
// The matrix is set up to preserve the luminance of the image.
// See http://graficaobscura.com/matrix/index.html
// Number are taken from https://msdn.microsoft.com/en-us/library/jj192162(v=vs.85).aspx
var matrix4X4 = new Matrix4x4
{
M11 = lumR + (cosradians * oneMinusLumR) - (sinradians * lumR),
M12 = lumR - (cosradians * lumR) - (sinradians * 0.143F),
M13 = lumR - (cosradians * lumR) - (sinradians * oneMinusLumR),
M21 = lumG - (cosradians * lumG) - (sinradians * lumG),
M22 = lumG + (cosradians * oneMinusLumG) + (sinradians * 0.140F),
M23 = lumG - (cosradians * lumG) + (sinradians * lumG),
M31 = lumB - (cosradians * lumB) + (sinradians * oneMinusLumB),
M32 = lumB - (cosradians * lumB) - (sinradians * 0.283F),
M33 = lumB + (cosradians * oneMinusLumB) + (sinradians * lumB),
M44 = 1
};
this.Matrix = matrix4X4;
}
public CieLchuv Convert(CieLuv input)
{
// Conversion algorithm described here:
// https://en.wikipedia.org/wiki/CIELUV#Cylindrical_representation_.28CIELCH.29
float l = input.L, a = input.U, b = input.V;
float c = MathF.Sqrt((a * a) + (b * b));
float hRadians = MathF.Atan2(b, a);
float hDegrees = MathFExtensions.RadianToDegree(hRadians);
// Wrap the angle round at 360.
hDegrees = hDegrees % 360;
// Make sure it's not negative.
while (hDegrees < 0)
{
hDegrees += 360;
}
return(new CieLchuv(l, c, hDegrees, input.WhitePoint));
}
public CieLch Convert(CieLab input)
{
// Conversion algorithm described here:
// https://en.wikipedia.org/wiki/Lab_color_space#Cylindrical_representation:_CIELCh_or_CIEHLC
float l = input.L, a = input.A, b = input.B;
float c = MathF.Sqrt((a * a) + (b * b));
float hRadians = MathF.Atan2(b, a);
float hDegrees = MathFExtensions.RadianToDegree(hRadians);
// Wrap the angle round at 360.
hDegrees = hDegrees % 360;
// Make sure it's not negative.
while (hDegrees < 0)
{
hDegrees += 360;
}
return(new CieLch(l, c, hDegrees, input.WhitePoint));
}
/// <summary> /// Creates a rotation matrix using the given rotation in degrees and a center point. /// </summary> /// <param name="degrees">The amount of rotation, in degrees.</param> /// <param name="centerPoint">The center point.</param> /// <returns>A rotation matrix.</returns> public static Matrix3x2 CreateRotationDegrees(float degrees, PointF centerPoint) => Matrix3x2.CreateRotation(MathFExtensions.DegreeToRadian(degrees), centerPoint);
/// <summary> /// Creates a rotation matrix using the given rotation in degrees. /// </summary> /// <param name="degrees">The amount of rotation, in degrees.</param> /// <returns>A rotation matrix.</returns> public static Matrix3x2 CreateRotationDegrees(float degrees) => Matrix3x2.CreateRotation(MathFExtensions.DegreeToRadian(degrees));
/// <summary> /// Creates a skew matrix from the given angles in degrees and a center point. /// </summary> /// <param name="degreesX">The X angle, in degrees.</param> /// <param name="degreesY">The Y angle, in degrees.</param> /// <param name="centerPoint">The center point.</param> /// <returns>A skew matrix.</returns> public static Matrix3x2 CreateSkewDegrees(float degreesX, float degreesY, PointF centerPoint) => Matrix3x2.CreateSkew(MathFExtensions.DegreeToRadian(degreesX), MathFExtensions.DegreeToRadian(degreesY), centerPoint);
/// <summary> /// Creates a skew matrix from the given angles in degrees. /// </summary> /// <param name="degreesX">The X angle, in degrees.</param> /// <param name="degreesY">The Y angle, in degrees.</param> /// <returns>A skew matrix.</returns> public static Matrix3x2 CreateSkewDegrees(float degreesX, float degreesY) => Matrix3x2.CreateSkew(MathFExtensions.DegreeToRadian(degreesX), MathFExtensions.DegreeToRadian(degreesY));
public void Convert_Degree_To_Radian()
{
Assert.Equal((float)(Math.PI / 2D), MathFExtensions.DegreeToRadian(90F), new FloatRoundingComparer(6));
}
public void Convert_Radian_To_Degree()
{
Assert.Equal(60F, MathFExtensions.RadianToDegree((float)(Math.PI / 3D)), new FloatRoundingComparer(5));
}
