1 files changed, 120 insertions, 0 deletions
diff --git a/Software/Visual_Studio/Tango.RemoteDesktop/Comparers/RasterBitmapComparer.cs b/Software/Visual_Studio/Tango.RemoteDesktop/Comparers/RasterBitmapComparer.cs
new file mode 100644
index 000000000..34250cc59
--- /dev/null
+++ b/Software/Visual_Studio/Tango.RemoteDesktop/Comparers/RasterBitmapComparer.cs
@@ -0,0 +1,120 @@
+using System;
+using System.Collections.Generic;
+using System.Drawing;
+using System.Drawing.Imaging;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Tango.RemoteDesktop.Frames;
+
+namespace Tango.RemoteDesktop.Comparers
+{
+    /// <summary>
+    /// Represents a raster <see cref="IBitmapComparer{TFrame}"/> comparer which will compare and return a <see cref="RasterFrame"/> difference.
+    /// </summary>
+    /// <seealso cref="Tango.RemoteDesktop.IBitmapComparer{Tango.RemoteDesktop.Frames.RasterFrame}" />
+    public class RasterBitmapComparer : IBitmapComparer<RasterFrame>
+    {
+        /// <summary>
+        /// Creates the difference as <see cref="RasterFrame"/>.
+        /// </summary>
+        /// <param name="previousBitmap">The previous bitmap.</param>
+        /// <param name="currentBitmap">The current bitmap.</param>
+        /// <returns></returns>
+        /// <exception cref="InvalidOperationException">
+        /// Cannot compare image. They are the same instance
+        /// or
+        /// Cannot compare image of different size.
+        /// </exception>
+        unsafe public BitmapComparerResult<RasterFrame> CreateDifference(Bitmap previousBitmap, Bitmap currentBitmap)
+        {
+            if (previousBitmap == null | currentBitmap == null)
+                throw new InvalidOperationException("Cannot compare image. They are the same instance");
+
+            if (previousBitmap.Height != currentBitmap.Height || previousBitmap.Width != currentBitmap.Width)
+                throw new InvalidOperationException("Cannot compare image of different size.");
+
+            bool hasDifference = false;
+
+            Color matchColor = Color.Transparent;
+
+            Bitmap diffImage = currentBitmap.Clone() as Bitmap;
+
+            int height = previousBitmap.Height;
+            int width = previousBitmap.Width;
+
+            BitmapData data1 = previousBitmap.LockBits(new Rectangle(0, 0, width, height),
+                                               ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
+            BitmapData data2 = currentBitmap.LockBits(new Rectangle(0, 0, width, height),
+                                               ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
+            BitmapData diffData = diffImage.LockBits(new Rectangle(0, 0, width, height),
+                                                   ImageLockMode.WriteOnly, PixelFormat.Format32bppArgb);
+
+            byte* data1Ptr = (byte*)data1.Scan0;
+            byte* data2Ptr = (byte*)data2.Scan0;
+            byte* diffPtr = (byte*)diffData.Scan0;
+
+            byte[] swapColor = new byte[4];
+            swapColor[0] = matchColor.B;
+            swapColor[1] = matchColor.G;
+            swapColor[2] = matchColor.R;
+            swapColor[3] = matchColor.A;
+
+            int rowPadding = data1.Stride - (previousBitmap.Width * 4);
+
+            // iterate over height (rows)
+            for (int i = 0; i < height; i++)
+            {
+                // iterate over width (columns)
+                for (int j = 0; j < width; j++)
+                {
+                    int same = 0;
+
+                    byte[] tmp = new byte[4];
+
+                    // compare pixels and copy new values into temporary array
+                    for (int x = 0; x < 4; x++)
+                    {
+                        tmp[x] = data2Ptr[0];
+                        if (data1Ptr[0] == data2Ptr[0])
+                        {
+                            same++;
+                        }
+                        data1Ptr++; // advance image1 ptr
+                        data2Ptr++; // advance image2 ptr
+                    }
+
+                    // swap color or add new values
+                    for (int x = 0; x < 4; x++)
+                    {
+                        diffPtr[0] = (same == 4) ? swapColor[x] : tmp[x];
+                        diffPtr++; // advance diff image ptr
+                    }
+
+                    if (same != 4)
+                    {
+                        hasDifference = true;
+                    }
+                }
+
+                // at the end of each column, skip extra padding
+                if (rowPadding > 0)
+                {
+                    data1Ptr += rowPadding;
+                    data2Ptr += rowPadding;
+                    diffPtr += rowPadding;
+                }
+            }
+
+            previousBitmap.UnlockBits(data1);
+            currentBitmap.UnlockBits(data2);
+            diffImage.UnlockBits(diffData);
+
+            return new BitmapComparerResult<RasterFrame>()
+            {
+                Frame = new RasterFrame(diffImage),
+                ContainsDifference = hasDifference
+            };
+        }
+    }
+}