public static void UpdateLayeredWindowHelper(Control control, Bitmap bmp) { IntPtr dC = Win32.GetDC(IntPtr.Zero); Win32.Point point = new Win32.Point(control.Left, control.Top); Win32.Size size = new Win32.Size(bmp.Width, bmp.Height); IntPtr intPtr = Win32.CreateCompatibleDC(IntPtr.Zero); IntPtr hbitmap = bmp.GetHbitmap(Color.Black); Win32.SelectObject(intPtr, hbitmap); Win32.Point point2 = new Win32.Point(0, 0); Win32.BlendFunction blendFunction = default(Win32.BlendFunction); blendFunction.BlendOp = 0; blendFunction.BlendFlags = 0; blendFunction.SourceConstantAlpha = 255; blendFunction.AlphaFormat = 1; Win32.UpdateLayeredWindow(control.Handle, dC, ref point, ref size, intPtr, ref point2, 0, ref blendFunction, 2); Win32.DeleteObject(hbitmap); Win32.DeleteDC(intPtr); Win32.ReleaseDC(IntPtr.Zero, dC); }
public static extern bool GetTextExtentExPoint(IntPtr hdc, string lpszStr, int cchString, int nMaxExtent, out int lpnFit, IntPtr alpDx, out Win32.Size lpSize);
public static extern bool UpdateLayeredWindow(IntPtr hwnd, IntPtr hdcDst, ref Win32.Point pptDst, ref Win32.Size psize, IntPtr hdcSrc, ref Win32.Point pptSrc, int crKey, ref Win32.BlendFunction pblend, int dwFlags);