Fixed a potential issue with GetWindowLong, using a wrapper which decides upon the IntPtr size which call needs to be made.

Fixed the corner cut to work with a CreateRoundRectRgn, but made if it cuts configurable so people can turn it off.
Added a CountColor method to ImageHelper.cs, which should be used to check if PrintWindow functions properly.

git-svn-id: http://svn.code.sf.net/p/greenshot/code/trunk@2236 7dccd23d-a4a3-4e1f-8c07-b4c1b4018ab4

GreenshotPlugin/Core/ImageHelper.cs

@@ -1074,6 +1074,37 @@ namespace GreenshotPlugin.Core {
 			return ResizeBitmap(sourceBitmap, maintainAspectRatio, false, Color.Empty, newWidth, newHeight, out throwAway);
 		}
 
+		/// <summary>
+		/// Count how many times the supplied color exists
+		/// </summary>
+		/// <param name="sourceBitmap">Bitmap to count the pixels of</param>
+		/// <param name="colorToCount">Color to count/param>
+		/// <param name="includeAlpha">true if Alpha needs to be checked</param>
+		/// <returns>int with the number of pixels which have colorToCount</returns>
+		public static int CountColor(Bitmap sourceBitmap, Color colorToCount, bool includeAlpha) {
+			int colors = 0;
+			int toCount = colorToCount.ToArgb();
+			if (!includeAlpha) {
+				toCount = toCount & 0xffffff;
+			}
+			using (BitmapBuffer bb = new BitmapBuffer(sourceBitmap, true)) {
+				bb.Lock();
+				for (int y = 0; y < bb.Height; y++) {
+					for (int x = 0; x < bb.Width; x++) {
+						int bitmapcolor = bb.GetColorAt(x, y).ToArgb();
+						if (!includeAlpha) {
+							bitmapcolor = bitmapcolor & 0xffffff;
+						}
+						if (bitmapcolor == toCount) {
+							colors++;
+						}
+					}
+				}
+				bb.Unlock();
+				return colors;
+			}
+		}
+
 		/// <summary>
 		/// Scale the bitmap, keeping aspect ratio, but the canvas will always have the specified size.
 		/// </summary>