public static void InvertScreenRect(IntPtr hwnd, Rectangle rect)
{
Winapi.RECT rect2;
var loc = Winapi.GetWindowRect(hwnd).Location;
rect.Offset(-loc.X, -loc.Y);
var hdc = Winapi.GetWindowDC(hwnd);
//top edge
rect2 = new Winapi.RECT(rect.Left, rect.Top, rect.Right, rect.Top + INVERT_BORDER);
InvertRect(hdc, ref rect2);
//left edge
rect2 = new Winapi.RECT(rect.Left, rect.Top + INVERT_BORDER, rect.Left + INVERT_BORDER, rect.Bottom - INVERT_BORDER);
InvertRect(hdc, ref rect2);
//right edge
rect2 = new Winapi.RECT(rect.Right - INVERT_BORDER, rect.Top + INVERT_BORDER, rect.Right, rect.Bottom - INVERT_BORDER);
InvertRect(hdc, ref rect2);
//bottom edge
rect2 = new Winapi.RECT(rect.Left, rect.Bottom - INVERT_BORDER, rect.Right, rect.Bottom);
InvertRect(hdc, ref rect2);
Winapi.ReleaseDC(hwnd, hdc);
}
static extern bool OffsetRect(ref Winapi.RECT lprc, int dx, int dy);
static extern bool SetRect(out Winapi.RECT lprc, int xLeft, int yTop, int xRight, int yBottom);
static extern bool InvertRect(IntPtr hDC, [In] ref Winapi.RECT lprc);
