public static void UpdateLayeredWindow(IntPtr hwnd, Point location, Bitmap bitmap, byte alpha)
{
try
{
BLENDFUNCTION blend = new BLENDFUNCTION();
blend.BlendOp = AlphaChannelFlags.AC_SRC_OVER;
blend.BlendFlags = 0;
blend.AlphaFormat = AlphaChannelFlags.AC_SRC_ALPHA;
blend.SourceConstantAlpha = alpha;
POINT srcLocation = new POINT();
POINT dstLocation = POINT.FromPoint(location);
SIZE dstSize = SIZE.FromSize(bitmap.Size);
IntPtr hdc = WinUserApi.GetWindowDC(hwnd);
IntPtr bmpDc = WinGdiApi.CreateCompatibleDC(hdc);
IntPtr hBitmap = bitmap.GetHbitmap(Color.FromArgb(0));
IntPtr originalBitmap = WinGdiApi.SelectObject(bmpDc, hBitmap);
WinUserApi.UpdateLayeredWindow(hwnd, IntPtr.Zero, ref dstLocation, ref dstSize, bmpDc, ref srcLocation, 0, ref blend, UpdateLayeredWindowFlags.ULW_ALPHA);
WinGdiApi.SelectObject(bmpDc, originalBitmap);
WinGdiApi.DeleteObject(hBitmap);
WinGdiApi.DeleteDC(bmpDc);
WinUserApi.ReleaseDC(hwnd, hdc);
}
catch
{
}
}
public static Bitmap PrintWindow(IntPtr hwnd)
{
RECT windowRect;
WinUserApi.GetWindowRect(hwnd, out windowRect);
IntPtr hdc = WinUserApi.GetWindowDC(hwnd);
Bitmap bmp = new Bitmap(windowRect.Width, windowRect.Height, PixelFormat.Format32bppArgb);
Graphics gfxBmp = Graphics.FromImage(bmp);
gfxBmp.FillRectangle(new SolidBrush(Color.FromArgb(0, 0, 0, 0)), new Rectangle(Point.Empty, bmp.Size));
IntPtr hdcBitmap = gfxBmp.GetHdc();
bool succeeded = WinUserApi.PrintWindow(hwnd, hdcBitmap, 0);
gfxBmp.ReleaseHdc(hdcBitmap);
if (!succeeded)
{
gfxBmp.FillRectangle(new SolidBrush(Color.Gray), new Rectangle(Point.Empty, bmp.Size));
}
IntPtr hRgn = WinGdiApi.CreateRectRgn(0, 0, 0, 0);
WinUserApi.GetWindowRgn(hwnd, hRgn);
Region region = Region.FromHrgn(hRgn);
if (!region.IsEmpty(gfxBmp))
{
gfxBmp.ExcludeClip(region);
gfxBmp.Clear(Color.FromArgb(0, 0, 0, 0));
}
region.Dispose();
WinGdiApi.DeleteObject(hRgn);
gfxBmp.Dispose();
WinUserApi.ReleaseDC(hwnd, hdc);
return(bmp);
}