private void FadeImages()
{
using (var sourceGraphics = Graphics.FromImage(_screenBuffer[_lastScreenBuffer]))
using (var destinationGraphics = Graphics.FromImage(_screenBuffer[_activeScreenBuffer]))
{
IntPtr sourceDC = IntPtr.Zero;
IntPtr sourceBitmapHandle = IntPtr.Zero;
IntPtr oldSourceObjectHandle = IntPtr.Zero;
IntPtr destinationDC = IntPtr.Zero;
IntPtr destinationBitmapHandle = IntPtr.Zero;
IntPtr oldDestinationObjectHandle = IntPtr.Zero;
try
{
sourceDC = sourceGraphics.GetHdc();
sourceBitmapHandle = _screenBuffer[_lastScreenBuffer].GetHbitmap();
oldSourceObjectHandle = Gdi32.SelectObject(sourceDC, sourceBitmapHandle);
if (oldSourceObjectHandle == IntPtr.Zero)
{
throw new Win32Exception();
}
destinationDC = destinationGraphics.GetHdc();
destinationBitmapHandle = _screenBuffer[_activeScreenBuffer].GetHbitmap();
oldDestinationObjectHandle = Gdi32.SelectObject(destinationDC, destinationBitmapHandle);
if (oldDestinationObjectHandle == IntPtr.Zero)
{
throw new Win32Exception();
}
var constantAlphaBlend = new Gdi32.BlendFunction
{
BlendOp = Gdi32.AC_SRC_OVER,
SourceConstantAlpha = 0x99,
};
if (!Gdi32.AlphaBlend(destinationDC, 0, 0, _screenBuffer[_activeScreenBuffer].Width, _screenBuffer[_activeScreenBuffer].Height,
sourceDC, 0, 0, _screenBuffer[_lastScreenBuffer].Width, _screenBuffer[_lastScreenBuffer].Height,
constantAlphaBlend))
{
throw new Win32Exception();
}
}
finally
{
if (oldDestinationObjectHandle != IntPtr.Zero)
{
Gdi32.SelectObject(destinationDC, oldDestinationObjectHandle);
}
if (destinationBitmapHandle != IntPtr.Zero)
{
Gdi32.DeleteObject(destinationBitmapHandle);
}
if (destinationDC != IntPtr.Zero)
{
destinationGraphics.ReleaseHdc(destinationDC);
}
if (oldSourceObjectHandle != IntPtr.Zero)
{
Gdi32.SelectObject(sourceDC, oldSourceObjectHandle);
}
if (sourceBitmapHandle != IntPtr.Zero)
{
Gdi32.DeleteObject(sourceBitmapHandle);
}
if (sourceDC != IntPtr.Zero)
{
sourceGraphics.ReleaseHdc(sourceDC);
}
}
}
}
