internal static FrameworkElement UpdateMask(UIView owner, UIView superView = null)
{
superView = superView ?? owner.Superview;
var layer = owner.Layer;
var clippingParentResult = GetClippingParent(owner);
if (
clippingParentResult.clippingParent != null &&
owner is FrameworkElement tfe
#if DEBUG
&& (CanClipSelector?.Invoke(owner) ?? true)
#endif
)
{
var clippingParent = clippingParentResult.clippingParent;
if (clippingParentResult.child is FrameworkElement cfe && !cfe.ClipChildrenToBounds)
{
// If the immediate child of the clipping parent is not clipping its children, then the
// clipping parent is its parent (Ellipse -> Canvas -> Grid -> StackPanel)
clippingParent = clippingParentResult.clippingParent.Superview;
}
var absolutePosition = ConvertOriginPointToView(owner, clippingParent);
var clippingBounds = clippingParent.Bounds;
if (clippingBounds != CGRect.Empty)
{
var maskLayer = new CoreAnimation.CAShapeLayer();
var maskRect = new CGRect(-absolutePosition.X, -absolutePosition.Y, clippingBounds.Width, clippingBounds.Height);
maskLayer.Path = UIBezierPath.FromRect(maskRect).CGPath;
layer.Mask = maskLayer;
if (typeof(UIElement).Log().IsEnabled(LogLevel.Debug))
{
typeof(UIElement).Log().LogDebug($"UpdateMask o:{owner.GetType()} p:{clippingParent.GetType()} f:{owner.Frame} b:{owner.Bounds} m:{maskRect} t:{owner.Transform}");
}
CreateDebugLayer(owner, layer, absolutePosition, clippingBounds);
return(clippingParent as FrameworkElement);
}
else
{
CreateDebugLayer(owner, layer, absolutePosition, clippingBounds);
if (typeof(UIElement).Log().IsEnabled(LogLevel.Debug))
{
typeof(UIElement).Log().LogDebug($"Mask disabled for CGRect.Empty parent o:{owner.GetType()}/{owner.GetHashCode():X8} p:{clippingParent.GetType()}/{clippingParent.GetHashCode():X8} f:{owner.Frame} b:{owner.Bounds} t:{owner.Transform}");
}
}
}
layer.Mask = null;
return(null);
}
private static void CreateDebugLayer(UIView owner, CALayer layer, CGPoint absolutePosition, CGRect clippingBounds)
{
if (FeatureConfiguration.UIElement.ShowClippingBounds)
{
if (_debugLayers == null)
{
_debugLayers = new Dictionary <UIView, CALayer>();
}
if (_debugLayers.TryGetValue(owner, out var previousLayer))
{
previousLayer.RemoveFromSuperLayer();
_debugLayers.Remove(owner);
}
var debugLayer = new CoreAnimation.CAShapeLayer();
var debugMaskRect = new CGRect(
-absolutePosition.X,
-absolutePosition.Y,
clippingBounds.Width < 1 ? 5 : clippingBounds.Width,
clippingBounds.Height < 1 ? 5 : clippingBounds.Height
);
debugLayer.Path = UIBezierPath.FromRect(debugMaskRect).CGPath;
debugLayer.Frame = debugMaskRect;
debugLayer.LineWidth = 2;
if (clippingBounds.Width == 0 && clippingBounds.Height == 0)
{
debugLayer.StrokeColor = Colors.Red;
}
else if (clippingBounds.Width < 1 || clippingBounds.Height < 1)
{
debugLayer.StrokeColor = Colors.Purple;
}
else
{
debugLayer.StrokeColor = Colors.Blue;
}
debugLayer.Opaque = false;
debugLayer.BackgroundColor = UIColor.Clear.CGColor;
debugLayer.FillColor = UIColor.Clear.CGColor;
debugLayer.MasksToBounds = false;
_debugLayers.Add(owner, debugLayer);
if (layer.Sublayers != null)
{
layer.InsertSublayer(debugLayer, layer.Sublayers.Length);
}
else
{
layer.AddSublayer(debugLayer);
}
}
}