private static void CopyGraphics(Graphics gxSrc, Graphics gxDest, int width, int height)
{
IntPtr destDc = gxDest.GetHdc();
IntPtr srcDc = gxSrc.GetHdc();
PlatformAPIs.BitBlt(destDc, 0, 0, width, height, srcDc, 0, 0, TernaryRasterOperations.SRCCOPY);
gxSrc.ReleaseHdc(srcDc);
gxDest.ReleaseHdc(destDc);
}
public static void DrawAlpha(Graphics gx, Bitmap image, byte transp, int x, int y)
{
using (Graphics gxSrc = Graphics.FromImage(image))
{
IntPtr hdcDst = gx.GetHdc();
IntPtr hdcSrc = gxSrc.GetHdc();
BlendFunction blendFunction = new BlendFunction();
blendFunction.BlendOp = (byte)BlendOperation.AC_SRC_OVER; // Only supported blend operation
blendFunction.BlendFlags = (byte)BlendFlags.Zero; // Documentation says put 0 here
blendFunction.SourceConstantAlpha = transp; // Constant alpha factor
blendFunction.AlphaFormat = (byte)0; // Don't look for per pixel alpha
PlatformAPIs.AlphaBlend(hdcDst, x, y, image.Width, image.Height, hdcSrc, 0, 0, image.Width, image.Height, blendFunction);
gx.ReleaseHdc(hdcDst); // Required cleanup to GetHdc()
gxSrc.ReleaseHdc(hdcSrc); // Required cleanup to GetHdc()
}
}
