Big refactor. Now we take Y=1 for white in CIE's XYZ color space

Author: castarco

ColorSharp/Properties/AssemblyInfo.cs

@@ -1,4 +1,4 @@
-/**
+/*
  * The MIT License (MIT)
  * Copyright (c) 2014 Andrés Correa Casablanca
  * 
@@ -21,10 +21,10 @@
  * SOFTWARE.
  */
 
-/**
-* Contributors:
-*  - Andrés Correa Casablanca <castarco@gmail.com , castarco@litipk.com>
-*/
+/*
+ * Contributors:
+ *  - Andrés Correa Casablanca <castarco@gmail.com , castarco@litipk.com>
+ */
 
 
 using System.Reflection;

ColorSharp/src/ColorSpaces/AConvertibleColor.cs

@@ -35,27 +35,13 @@ namespace Litipk.ColorSharp
 {
 	namespace ColorSpaces
 	{
-		// TODO : Refactor to allow static conversors
-		public delegate T ColorConversor<out T> (ConversionStrategy strategy=ConversionStrategy.Default) where T : AConvertibleColor;
-
 		public abstract class AConvertibleColor
 		{
-			#region constants
-
-			const int MAX_ACCEPTABLE_PATH_LENGH = 32;
-
-			#endregion
-
-
 			#region properties
 
 			// If this "color" comes from another data source, then we keep the original data.
 			protected AConvertibleColor DataSource = null;
 
-			// TODO : Make it private static... (and add accessors)
-			//  delegates
-			protected readonly Dictionary<Type, ColorConversor<AConvertibleColor>> Conversors = new Dictionary<Type, ColorConversor<AConvertibleColor>>();
-
 			#endregion
 
 
@@ -72,116 +58,39 @@ protected AConvertibleColor(AConvertibleColor dataSource = null)
 
 			#region conversion skeleton
 
-			// Tells us the number of needed steps to convert the object to another color space.
-			int ConversionPathLength(Type target, List<Type> visited=null)
+			public T ConvertTo<T> (ConversionStrategy strategy=ConversionStrategy.Default) where T : AConvertibleColor
 			{
-				if (Conversors.ContainsKey (target)) {
-					// TODO: This should depend on the inclusion relations between color spaces
-					return 1;
-				}
-
-				int pathLength = MAX_ACCEPTABLE_PATH_LENGH + 1;
-
-				Type tt = this.GetType ();
-
-				if (visited == null) {
-					visited = new List<Type> { tt };
-				} else {
-					// We make a copy to avoid problems
-					visited = new List<Type> (visited);
-					if (!visited.Contains (tt)) {
-						visited.Add (tt);
-					}
-				}
-
-				foreach (Type k in Conversors.Keys) {
-					if (visited.Contains (k)) {
-						continue;
-					}
-
-					int tmpCpl = 1 + ((AConvertibleColor)Activator.CreateInstance(k)).ConversionPathLength (
-						target, visited
-					);
-
-					pathLength = Math.Min (pathLength, tmpCpl);
-				}
-
-				return pathLength;
-			}
-
-			public T ConvertTo<T> (ConversionStrategy strategy=ConversionStrategy.Default, List<Type> visited = null) where T : AConvertibleColor
-			{
-				int basePathLength, dataSourcePathLength;
-
 				Type t = typeof(T);
 				Type tt = GetType ();
-				Type ist = null; // Intermediate color space type
 
 				if (t == tt) {
 					// Dumb conversion
 					return (T)(AConvertibleColor)this;
 				}
 
-				// We are going to compare the conversion path lengths in order to chose the best option
-				// (with least precission loss).
 				if (DataSource != null) {
 					if (DataSource.GetType () == t) {
-						// Recovering original data
 						return (T)DataSource;
 					}
 
-					dataSourcePathLength = DataSource.ConversionPathLength (t, new List<Type> {tt});
-				} else {
-					dataSourcePathLength = MAX_ACCEPTABLE_PATH_LENGH;
-				}
-
-				if (visited == null) {
-					visited = new List<Type> { tt };
-				} else {
-					// We make a copy to avoid problems
-					visited = new List<Type> (visited);
-					if (!visited.Contains (tt)) {
-						visited.Add (tt);
-					}
-				}
-
-				if (Conversors.ContainsKey (t)) {
-					// We don't use the direct conversor because maybe we can use the dataSource direct conversor
-					basePathLength = 1;
-				} else {
-					basePathLength = MAX_ACCEPTABLE_PATH_LENGH + 1;
-
-					foreach(Type k in Conversors.Keys)
-					{
-						if (visited.Contains (k)) {
-							continue;
-						}
-
-						int tmpCpl = 1 + ((AConvertibleColor)Activator.CreateInstance(k)).ConversionPathLength (
-							t, visited
-						);
-
-						if (tmpCpl < basePathLength) {
-							ist = k;
-							basePathLength = tmpCpl;
-						}
-					}
+					return DataSource.ConvertTo<T> (strategy);
 				}
 
-				if (dataSourcePathLength > MAX_ACCEPTABLE_PATH_LENGH && basePathLength > MAX_ACCEPTABLE_PATH_LENGH) {
-					throw new InvalidCastException ("Unable to find a conversion path to this color space.");
-				}
+				return InnerConvertTo<T> (strategy);
+			}
 
-				if (DataSource != null && dataSourcePathLength <= basePathLength + 1) {
-					return DataSource.ConvertTo<T> (strategy);
-				}
+			protected T InnerConvertTo<T> (ConversionStrategy strategy = ConversionStrategy.Default) where T : AConvertibleColor
+			{
+				Type t = typeof(T);
 
-				if (basePathLength == 1) {
-					return (T)Conversors [t] (strategy);
-				}
+				if (t == typeof(CIEXYZ))
+					return (T)(AConvertibleColor)ToCIEXYZ (strategy);
+				if (t == typeof(CIExyY))
+					return (T)(AConvertibleColor)ToCIExyY(strategy);
+				if (t == typeof(SRGB))
+					return (T)(AConvertibleColor)ToSRGB (strategy);
 
-				visited.Add (ist);
-				return Conversors [ist] ().ConvertTo<T>(strategy, visited);
+				throw new NotImplementedException ("This conversion isn't implemented.");
 			}
 
 			#endregion
@@ -194,6 +103,21 @@ public T ConvertTo<T> (ConversionStrategy strategy=ConversionStrategy.Default, L
 			 */
 			public abstract bool IsInsideColorSpace ();
 
+			/**
+			 * <summary>Converts the color sample to a CIE's 1931 XYZ color sample.</summary>
+			 */
+			public abstract CIEXYZ ToCIEXYZ(ConversionStrategy strategy = ConversionStrategy.Default);
+
+			/**
+			 * <summary>Converts the color sample to a CIE's 1931 xyY color sample.</summary>
+			 */
+			public abstract CIExyY ToCIExyY (ConversionStrategy strategy = ConversionStrategy.Default);
+
+			/**
+			 * <summary>Converts the color sample to an HP's & Microsoft's 1996 sRGB sample.</summary>
+			 */
+			public abstract SRGB ToSRGB(ConversionStrategy strategy = ConversionStrategy.Default);
+
 			#endregion
 		}
 	}

ColorSharp/src/ColorSpaces/CIEXYZ.cs

@@ -36,34 +36,40 @@ namespace Litipk.ColorSharp
 	namespace ColorSpaces
 	{
 		/**
-		 * CIE 1931 (2º) XYZ Color Space.
+		 * <summary>CIE's 1931 (2º) XYZ Color Space.</summary>
 		 */
 		public sealed class CIEXYZ : AConvertibleColor
 		{
-			#region readonly properties
+			#region properties
 
-			public readonly double X, Y, Z;
+			/**
+			 * <value>X component of the CIE's 1931 XYZ color space.</value>
+			 */
+			public readonly double X;
+
+			/**
+			 * <value>Y component of the CIE's 1931 XYZ color space.</value>
+			 */
+			public readonly double Y;
+
+			/**
+			 * <value>Z component of the CIE's 1931 XYZ color space.</value>
+			 */
+			public readonly double Z;
 
 			#endregion
 
 
 			#region constructors
 
-			public CIEXYZ() {
-				Conversors.Add (typeof(SRGB), ToSRGB);
-				Conversors.Add (typeof(CIExyY), ToxyY);
-			}
-
 			/**
-			 * This constructor "installs" the conversor methods into the instance
+			 * <summary>Creates a new color sample in the CIE's 1931 xyY color space</summary>
+			 * <param name="X">CIE's 1931 XYZ X coordinate</param>
+			 * <param name="Y">CIE's 1931 XYZ Y coordinate</param>
+			 * <param name="Z">CIE's 1931 XYZ Z coordinate</param>
+			 * <param name="dataSource">If you aren't working with ColorSharp internals, don't use this parameter</param>
 			 */
-			private CIEXYZ(AConvertibleColor dataSource=null) : base(dataSource) {
-				Conversors.Add (typeof(SRGB), ToSRGB);
-				Conversors.Add (typeof(CIExyY), ToxyY);
-			}
-
-			// Constructor
-			public CIEXYZ (double X, double Y, double Z, AConvertibleColor dataSource=null) : this(dataSource)
+			public CIEXYZ (double X, double Y, double Z, AConvertibleColor dataSource=null) : base(dataSource)
 			{
 				this.X = X;
 				this.Y = Y;
@@ -73,53 +79,74 @@ public CIEXYZ (double X, double Y, double Z, AConvertibleColor dataSource=null)
 			#endregion
 
 
-			#region conversors
+			#region AConvertibleColor methods
 
-			public CIExyY ToxyY (ConversionStrategy strategy=ConversionStrategy.Default)
+			/**
+			 * <inheritdoc />
+			 */
+			public override bool IsInsideColorSpace()
 			{
-				double XYZ = X + Y + Z;
-				return new CIExyY (X / XYZ, Y / XYZ, Y, DataSource ?? this);
+				return ToCIExyY ().IsInsideColorSpace ();
+			}
+
+			/**
+			 * <inheritdoc />
+			 */
+			public override CIEXYZ ToCIEXYZ (ConversionStrategy strategy=ConversionStrategy.Default)
+			{
+				return this;
 			}
 
 			/**
-			 * Converts the CIE 1931 XYZ sample to a HP's & Microsoft's 1996 sRGB sample
+			 * <inheritdoc />
 			 */
-			public SRGB ToSRGB (ConversionStrategy strategy=ConversionStrategy.Default)
+			public override CIExyY ToCIExyY (ConversionStrategy strategy=ConversionStrategy.Default)
 			{
-				double tx = X / 100.0;
-				double ty = Y / 100.0;
-				double tz = Z / 100.0;
+				double XYZ = X + Y + Z;
+				return new CIExyY (X / XYZ, Y / XYZ, Y, DataSource ?? this);
+			}
 
+			/**
+			* <inheritdoc />
+			*/
+			public override SRGB ToSRGB (ConversionStrategy strategy=ConversionStrategy.Default)
+			{
 				// Linear transformation
-				double r = tx * 3.2406 + ty * -1.5372 + tz * -0.4986;
-				double g = tx * -0.9689 + ty * 1.8758 + tz * 0.0415;
-				double b = tx * 0.0557 + ty * -0.2040 + tz * 1.0570;
+				double r = X * 3.2406 + Y * -1.5372 + Z * -0.4986;
+				double g = X * -0.9689 + Y * 1.8758 + Z * 0.0415;
+				double b = X * 0.0557 + Y * -0.2040 + Z * 1.0570;
 
 				// Gamma correction
 				r = r > 0.0031308 ? 1.055 * Math.Pow(r, 1 / 2.4) - 0.055 : 12.92 * r;
 				g = g > 0.0031308 ? 1.055 * Math.Pow(g, 1 / 2.4) - 0.055 : 12.92 * g;
 				b = b > 0.0031308 ? 1.055 * Math.Pow(b, 1 / 2.4) - 0.055 : 12.92 * b;
 
-				if ((strategy & ConversionStrategy.ForceStretching) != 0) {
+				if ((strategy & ConversionStrategy.ForceLowStretch) != 0) {
 					double minChannelValue = Math.Min (r, Math.Min (g, b));
 
 					if (minChannelValue < 0.0) {
 						r -= minChannelValue;
 						g -= minChannelValue;
 						b -= minChannelValue;
 					}
-				} else if ((strategy & ConversionStrategy.ForceTruncating) != 0) {
+				} else if ((strategy & ConversionStrategy.ForceLowTruncate) != 0) {
 					r = Math.Max (0.0, r);
 					g = Math.Max (0.0, g);
 					b = Math.Max (0.0, b);
 				}
 
-				double maxChannelValue = Math.Max (r, Math.Max (g, b));
+				if ((strategy & ConversionStrategy.ForceHighStretch) != 0) {
+					double maxChannelValue = Math.Max (r, Math.Max (g, b));
 
-				if (maxChannelValue > 1.0) {
-					r = r / maxChannelValue;
-					g = g / maxChannelValue;
-					b = b / maxChannelValue;
+					if (maxChannelValue > 1.0) {
+						r = r / maxChannelValue;
+						g = g / maxChannelValue;
+						b = b / maxChannelValue;
+					}
+				} else if ((strategy & ConversionStrategy.ForceHighTruncate) != 0) {
+					r = Math.Min (1.0, r);
+					g = Math.Min (1.0, g);
+					b = Math.Min (1.0, b);
 				}
 
 				return new SRGB(r, g, b, DataSource ?? this);
@@ -128,13 +155,11 @@ public SRGB ToSRGB (ConversionStrategy strategy=ConversionStrategy.Default)
 			#endregion
 
 
-			#region inherited methods
-
-			public override bool IsInsideColorSpace()
-			{
-				return ConvertTo<CIExyY> ().IsInsideColorSpace ();
-			}
+			#region Object methods
 
+			/**
+			 * <inheritdoc />
+			 */
 			public override bool Equals(Object obj)
 			{
 				CIEXYZ xyzObj = obj as CIEXYZ; 
@@ -148,6 +173,10 @@ public override bool Equals(Object obj)
 					Math.Abs (Z - xyzObj.Z) <= double.Epsilon
 				);
 			}
+
+			/**
+			 * <inheritdoc />
+			 */
 			public override int GetHashCode ()
 			{
 				int hash = 23;
@@ -159,7 +188,6 @@ public override int GetHashCode ()
 				return hash;
 			}
 
-
 			#endregion
 		}
 	}