Get the color of the current color screen filter

Question

The following code Sets the screen color filter to a specific color.

How can I get screen color instead of GET?

[DllImport("GDI32.dll")] private unsafe static extern bool SetDeviceGammaRamp(IntPtr hdc, void* ramp); private static IntPtr hdc; public unsafe bool SetLCDbrightness(Color c) { short red = cR; short green = cG; short blue = cB; Graphics gg = Graphics.FromHwnd(IntPtr.Zero); hdc = gg.GetHdc(); short* gArray = stackalloc short[3 * 256]; short* idx = gArray; short brightness = 0; for (int j = 0; j < 3; j++) { if (j == 0) brightness = red; if (j == 1) brightness = green; if (j == 2) brightness = blue; for (int i = 0; i < 256; i++) { int arrayVal = i * (brightness); if (arrayVal > 65535) arrayVal = 65535; *idx = (short)arrayVal; idx++; } } // For some reason, this always returns false? bool retVal = SetDeviceGammaRamp(hdc, gArray); gg.Dispose(); return false; } 

Answer 1

I adapted this other post to form the following answer:

 [DllImport("gdi32.dll")] public static extern int GetDeviceGammaRamp(IntPtr hDC, ref RAMP lpRamp); [DllImport("user32.dll")] public static extern IntPtr GetDC(IntPtr hWnd); [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)] public struct RAMP { [MarshalAs(UnmanagedType.ByValArray, SizeConst = 256)] public UInt16[] Red; [MarshalAs(UnmanagedType.ByValArray, SizeConst = 256)] public UInt16[] Green; [MarshalAs(UnmanagedType.ByValArray, SizeConst = 256)] public UInt16[] Blue; } private Color getScreenColor() { RAMP r = new RAMP(); GetDeviceGammaRamp(GetDC(IntPtr.Zero), ref r); return Color.FromArgb(r.Red[1], r.Green[1], r.Blue[1]); }