public static Color GetPixelColor(int x, int y) { IntPtr hdc = NativeMethods.GetDC(IntPtr.Zero); uint pixel = NativeMethods.GetPixel(hdc, x, y); NativeMethods.ReleaseDC(IntPtr.Zero, hdc); return(Color.FromArgb((int)(pixel & 0x000000FF), (int)(pixel & 0x0000FF00) >> 8, (int)(pixel & 0x00FF0000) >> 16)); }
public void SelectBitmap(Bitmap bitmap, int opacity) { if (bitmap.PixelFormat != PixelFormat.Format32bppArgb) { throw new ApplicationException("The bitmap must be 32bpp with alpha-channel."); } IntPtr screenDc = NativeMethods.GetDC(IntPtr.Zero); IntPtr memDc = NativeMethods.CreateCompatibleDC(screenDc); IntPtr hBitmap = IntPtr.Zero; IntPtr hOldBitmap = IntPtr.Zero; try { hBitmap = bitmap.GetHbitmap(Color.FromArgb(0)); hOldBitmap = NativeMethods.SelectObject(memDc, hBitmap); SIZE newSize = new SIZE(bitmap.Width, bitmap.Height); POINT sourceLocation = new POINT(0, 0); POINT newLocation = new POINT(this.Left, this.Top); BLENDFUNCTION blend = new BLENDFUNCTION(); blend.BlendOp = NativeMethods.AC_SRC_OVER; blend.BlendFlags = 0; blend.SourceConstantAlpha = (byte)opacity; blend.AlphaFormat = NativeMethods.AC_SRC_ALPHA; NativeMethods.UpdateLayeredWindow(this.Handle, screenDc, ref newLocation, ref newSize, memDc, ref sourceLocation, 0, ref blend, NativeMethods.ULW_ALPHA); } finally { NativeMethods.ReleaseDC(IntPtr.Zero, screenDc); if (hBitmap != IntPtr.Zero) { NativeMethods.SelectObject(memDc, hOldBitmap); NativeMethods.DeleteObject(hBitmap); } NativeMethods.DeleteDC(memDc); } }