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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
};
}
}
}
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