Added ReduceColorEffect (using the WuQuantizer in the effect). Changed the way the ApplyEffect works, an effect might decide to do nothing and return null.

git-svn-id: http://svn.code.sf.net/p/greenshot/code/trunk@2471 7dccd23d-a4a3-4e1f-8c07-b4c1b4018ab4

GreenshotPlugin/Core/Effects.cs

@@ -138,6 +138,34 @@ namespace Greenshot.Core {
 		}
 	}
 
+	/// <summary>
+	/// ReduceColorsEffect
+	/// </summary>
+	public class ReduceColorsEffect : IEffect {
+		private static log4net.ILog LOG = log4net.LogManager.GetLogger(typeof(ReduceColorsEffect));
+		public ReduceColorsEffect() : base() {
+			Colors = 256;
+		}
+		public int Colors {
+			get;
+			set;
+		}
+		public Image Apply(Image sourceImage, out Point offsetChange) {
+			offsetChange = Point.Empty;
+			using (WuQuantizer quantizer = new WuQuantizer((Bitmap)sourceImage)) {
+				int colorCount = quantizer.GetColorCount();
+				if (colorCount > Colors) {
+					try {
+						return quantizer.GetQuantizedImage(Colors);
+					} catch (Exception e) {
+						LOG.Warn("Error occurred while Quantizing the image, ignoring and using original. Error: ", e);
+					}
+				}
+			}
+			return null;
+		}
+	}
+
 	/// <summary>
 	/// InvertEffect
 	/// </summary>

GreenshotPlugin/Core/ImageHelper.cs

@@ -357,18 +357,20 @@ namespace GreenshotPlugin.Core {
 			// Default out value for the offset, will be modified there where needed
 			offset = new Point(0, 0);
 			Point tmpPoint;
-			Image tmpImage = null;
 			foreach (IEffect effect in effects) {
-				tmpImage = effect.Apply(currentImage, out tmpPoint);
-				offset.Offset(tmpPoint);
-				if (disposeImage) {
-					currentImage.Dispose();
+				Image tmpImage = effect.Apply(currentImage, out tmpPoint);
+				if (tmpImage != null) {
+					offset.Offset(tmpPoint);
+					if (disposeImage) {
+						currentImage.Dispose();
+					}
+					currentImage = tmpImage;
+					tmpImage = null;
+					// Make sure the "new" image is disposed
+					disposeImage = true;
 				}
-				currentImage = tmpImage;
-				// Make sure the "new" image is disposed
-				disposeImage = true;
 			}
-			return tmpImage;
+			return currentImage;
 		}
 
 		/// <summary>