private static void CreateAndCombineRoundRectRgn(IntPtr hrgnSource, Rect region, double radius)
{
var hrgn = IntPtr.Zero;
try
{
hrgn = CreateRoundRectRgn(region, radius);
var result = NativeMethods.CombineRgn(hrgnSource, hrgnSource, hrgn, RGN.OR);
if (result == CombineRgnResult.ERROR)
{
throw new InvalidOperationException("Unable to combine two HRGNs.");
}
}
catch
{
PlatformUtil.SafeDeleteObject(ref hrgn);
throw;
}
}