private void UpdateLayeredWindow(Point point, Size size, byte alpha)
{
Bitmap bitmap1 = new Bitmap(size.Width, size.Height, PixelFormat.Format32bppArgb);
using (Graphics graphics1 = Graphics.FromImage(bitmap1))
{
Rectangle rectangle1;
SIZE size1;
POINT point1;
POINT point2;
BLENDFUNCTION blendfunction1;
rectangle1 = new Rectangle(0, 0, size.Width, size.Height);
this.OnPaint(new PaintEventArgs(graphics1, rectangle1));
IntPtr ptr1 = User32.GetDC(IntPtr.Zero);
IntPtr ptr2 = Gdi32.CreateCompatibleDC(ptr1);
IntPtr ptr3 = bitmap1.GetHbitmap(Color.FromArgb(0));
IntPtr ptr4 = Gdi32.SelectObject(ptr2, ptr3);
size1.cx = size.Width;
size1.cy = size.Height;
point1.x = point.X;
point1.y = point.Y;
point2.x = 0;
point2.y = 0;
blendfunction1 = new BLENDFUNCTION();
blendfunction1.BlendOp = 0;
blendfunction1.BlendFlags = 0;
blendfunction1.SourceConstantAlpha = alpha;
blendfunction1.AlphaFormat = 1;
User32.UpdateLayeredWindow(base.Handle, ptr1, ref point1, ref size1, ptr2, ref point2, 0, ref blendfunction1, 2);
Gdi32.SelectObject(ptr2, ptr4);
User32.ReleaseDC(IntPtr.Zero, ptr1);
Gdi32.DeleteObject(ptr3);
Gdi32.DeleteDC(ptr2);
}
}
internal static extern bool UpdateLayeredWindow(IntPtr hwnd, IntPtr hdcDst, ref POINT pptDst, ref SIZE psize, IntPtr hdcSrc, ref POINT pprSrc, int crKey, ref BLENDFUNCTION pblend, int dwFlags);
