public bool IsOverlapped()
{
if (_blurValues.BlurWhenFocusLost ||
!PI.IsWindowVisible(_parentForm.Handle)
)
{
return(false);
}
IntPtr hWnd = _parentForm.Handle;
// The set is used to make calling GetWindow in a loop stable by checking if we have already
// visited the window returned by GetWindow. This avoids the possibility of an infinite loop.
var visited = new HashSet <IntPtr> {
hWnd
};
try
{
Form activeForm = Form.ActiveForm;
if (activeForm != null)
{
visited.Add(activeForm.Handle);
}
visited.Add(_visualBlur.Handle);
PI.RECT thisRect = new();
PI.GetWindowRect(hWnd, ref thisRect);
while ((hWnd = PI.GetWindow(hWnd, PI.GetWindowType.GW_HWNDPREV)) != IntPtr.Zero &&
!visited.Contains(hWnd))
{
visited.Add(hWnd);
PI.RECT testRect = new();
if (PI.IsWindowVisible(hWnd) &&
PI.GetWindowRect(hWnd, ref testRect) &&
PI.IntersectRect(out _, ref thisRect, ref testRect)
)
{
return(true);
}
}
return(false);
}
finally
{
// Attempt to clear sooner to allow handles to be released.
visited.Clear();
visited = null;
}
}
