internal override Point GetPosition(IInputElement relativeTo)
{
VerifyAccess();
// Validate that relativeTo is either a UIElement or a ContentElement
if (relativeTo != null && !InputElement.IsValid(relativeTo))
{
throw new InvalidOperationException();
}
PresentationSource relativePresentationSource = null;
if (relativeTo != null)
{
DependencyObject dependencyObject = relativeTo as DependencyObject;
DependencyObject containingVisual = InputElement.GetContainingVisual(dependencyObject);
if (containingVisual != null)
{
relativePresentationSource = PresentationSource.CriticalFromVisual(containingVisual);
}
}
else
{
if (_inputSource != null)
{
relativePresentationSource = _inputSource.Value;
}
}
// Verify that we have a valid PresentationSource with a valid RootVisual
// - if we don't we won't be able to invoke ClientToRoot or TranslatePoint and
// we will just return 0,0
if (relativePresentationSource == null || relativePresentationSource.RootVisual == null)
{
return(new Point(0, 0));
}
Point curPoint = new Point(_pointerData.Info.ptPixelLocationRaw.X, _pointerData.Info.ptPixelLocationRaw.Y);
Point ptClient = PointUtil.ScreenToClient(curPoint, relativePresentationSource);
Point ptRoot = PointUtil.ClientToRoot(ptClient, relativePresentationSource);
Point ptRelative = InputElement.TranslatePoint(ptRoot, relativePresentationSource.RootVisual, (DependencyObject)relativeTo);
return(ptRelative);
}