Added GDIplus.cs, this contains a GDI+ wrapper. Currently there is the ApplyBlur which applies a Gaussian blur effect on the specified rectangle of the passed bitmap.

git-svn-id: http://svn.code.sf.net/p/greenshot/code/trunk@2489 7dccd23d-a4a3-4e1f-8c07-b4c1b4018ab4

GreenshotPlugin/UnmanagedHelpers/GDIplus.cs

@@ -0,0 +1,114 @@
+/*
+ * Greenshot - a free and open source screenshot tool
+ * Copyright (C) 2007-2013  Thomas Braun, Jens Klingen, Robin Krom
+ * 
+ * For more information see: http://getgreenshot.org/
+ * The Greenshot project is hosted on Sourceforge: http://sourceforge.net/projects/greenshot/
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 1 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+using System;
+using System.Drawing;
+using System.Runtime.InteropServices;
+using System.Security;
+using Microsoft.Win32.SafeHandles;
+using System.Reflection;
+
+namespace GreenshotPlugin.UnmanagedHelpers {
+	/// <summary>
+	/// Contains members that specify the nature of a Gaussian blur.
+	/// </summary>
+	/// <remarks>Cannot be pinned with GCHandle due to bool value.</remarks>
+	[StructLayout(LayoutKind.Sequential, Pack = 1)]
+	internal struct BlurParams {
+		/// <summary>
+		/// Real number that specifies the blur radius (the radius of the Gaussian convolution kernel) in 
+		/// pixels. The radius must be in the range 0 through 255. As the radius increases, the resulting 
+		/// bitmap becomes more blurry.
+		/// </summary>
+		public float Radius;
+
+		/// <summary>
+		/// Boolean value that specifies whether the bitmap expands by an amount equal to the blur radius. 
+		/// If TRUE, the bitmap expands by an amount equal to the radius so that it can have soft edges. 
+		/// If FALSE, the bitmap remains the same size and the soft edges are clipped.
+		/// </summary>
+		public bool ExpandEdges;
+	}
+
+	/// <summary>
+	/// GDIplus Helpers
+	/// </summary>
+	public static class GDIplus {
+		[DllImport("gdiplus.dll", SetLastError = true, ExactSpelling = true, CharSet = CharSet.Unicode)]
+		private static extern int GdipBitmapApplyEffect(IntPtr bitmap, IntPtr effect, ref RECT rectOfInterest, bool useAuxData, IntPtr auxData, int auxDataSize);
+		[DllImport("gdiplus.dll", SetLastError = true, ExactSpelling = true, CharSet = CharSet.Unicode)]
+		private static extern int GdipSetEffectParameters(IntPtr effect, IntPtr parameters, uint size);
+		[DllImport("gdiplus.dll", SetLastError = true, ExactSpelling = true, CharSet = CharSet.Unicode)]
+		private static extern int GdipCreateEffect(Guid guid, out IntPtr effect);
+		[DllImport("gdiplus.dll", SetLastError = true, ExactSpelling = true, CharSet = CharSet.Unicode)]
+		private static extern int GdipDeleteEffect(IntPtr effect);
+		private static Guid BlurEffectGuid = new Guid("{633C80A4-1843-482B-9EF2-BE2834C5FDD4}");
+
+		internal static TResult GetPrivateField<TResult>(object obj, string fieldName) {
+			if (obj == null) {
+				return default(TResult);
+			}
+			Type ltType = obj.GetType();
+			FieldInfo lfiFieldInfo = ltType.GetField( fieldName,System.Reflection.BindingFlags.GetField |System.Reflection.BindingFlags.Instance |System.Reflection.BindingFlags.NonPublic);
+			if (lfiFieldInfo != null) {
+				return (TResult)lfiFieldInfo.GetValue(obj);
+			} else {
+				throw new InvalidOperationException(string.Format("Instance field '{0}' could not be located in object of type '{1}'.",fieldName, obj.GetType().FullName));
+			}
+		}
+
+		/// <summary>
+		/// Use the GDI+ blur effect on the bitmap
+		/// </summary>
+		/// <param name="destinationBitmap">Bitmap to apply the effect to</param>
+		/// <param name="area">Rectangle to apply the blur effect to</param>
+		/// <param name="radius">0-255</param>
+		/// <returns>false if there is no GDI+ available or an exception occured</returns>
+		public static bool ApplyBlur(Bitmap destinationBitmap, Rectangle area, float radius) {
+			if (Environment.OSVersion.Version.Major < 6) {
+				return false;
+			}
+			try {
+				BlurParams blurParams = new BlurParams();
+				blurParams.Radius = radius;
+				blurParams.ExpandEdges = false;
+				IntPtr hBlurParams = Marshal.AllocHGlobal(Marshal.SizeOf(blurParams));
+				Marshal.StructureToPtr(blurParams, hBlurParams, true);
+
+				uint paramsSize = (uint)Marshal.SizeOf(blurParams);
+
+				IntPtr hEffect = IntPtr.Zero;
+
+				int status = GdipCreateEffect(BlurEffectGuid, out hEffect);
+				GdipSetEffectParameters(hEffect, hBlurParams, paramsSize);
+
+				//IntPtr hBitmap = destinationBitmap.GetHbitmap();
+				IntPtr hBitmap = GetPrivateField<IntPtr>(destinationBitmap, "nativeImage");
+				RECT rec = new RECT(area);
+				GdipBitmapApplyEffect(hBitmap, hEffect, ref rec, false, IntPtr.Zero, 0);
+				GdipDeleteEffect(hEffect);
+				Marshal.FreeHGlobal(hBlurParams);
+				return true;
+			} catch (Exception ex) {
+				return false;
+			}
+		}
+	}
+}