[longomatch] Add a YCbCr color format

[Andoni Morales Alastruey <amorales src gnome org>]

commit 7e8b95dea4cba55b601e9eb675cd0c672d625bb7
Author: Andoni Morales Alastruey <ylatuya gmail com>
Date:   Fri Aug 1 20:38:26 2014 +0200

    Add a YCbCr color format

 LongoMatch.Core/Common/Color.cs |   49 ++++++++++++++++++++++++++++++++++++++-
 1 files changed, 48 insertions(+), 1 deletions(-)
---
diff --git a/LongoMatch.Core/Common/Color.cs b/LongoMatch.Core/Common/Color.cs
index f462fd7..53dcb2e 100644
--- a/LongoMatch.Core/Common/Color.cs
+++ b/LongoMatch.Core/Common/Color.cs
@@ -94,6 +94,53 @@ namespace LongoMatch.Common
                static public Color Red1 = new Color (255, 51, 0);
                static public Color Blue1 = new Color (0, 153, 255);
                static public Color Yellow = new Color (255, 255, 0);
+
        }
-}
 
+
+       public class YCbCrColor {
+
+               public YCbCrColor (byte y, byte cb, byte cr) {
+                       Y = y;
+                       Cb = cb;
+                       Cr = cr;
+               }
+
+               public byte Y {
+                       get;
+                       set;
+               }
+
+               public byte Cb {
+                       get;
+                       set;
+               }
+
+               public byte Cr {
+                       get;
+                       set;
+               }
+
+               public static YCbCrColor YCbCrFromColor (Color c) {
+                       byte Y, Cb, Cr;
+
+                       Y = (byte) (16 + 0.257 * c.R + 0.504 * c.G + 0.098 * c.B);
+                       Cb = (byte) (128 - 0.148 * c.R - 0.291 * c.G + 0.439 * c.B);
+                       Cr = (byte) (128 + 0.439 * c.R - 0.396 * c.G - 0.071 * c.B);
+                       return new YCbCrColor (Y, Cb, Cr);
+               }
+
+               public static Color ColorFromYCbCr (YCbCrColor c) {
+                       double r, g, b;
+
+                       r = (1.164 * (c.Y - 16) + 1.596 * (c.Cr - 128));
+                       g = (1.164 * (c.Y - 16) - 0.392 * (c.Cb - 128) - 0.813 * (c.Cr - 128));
+                       b = (1.164 * (c.Y - 16) + 2.017 * (c.Cb - 128));
+
+                       return new Color (
+                               (byte) Math.Max(0, Math.Min (r, 255)),
+                               (byte) Math.Max(0, Math.Min (g, 255)),
+                               (byte) Math.Max(0, Math.Min (b, 255)));
+               }
+       }
+}