LayerVisual Class

Definition

Namespace:

Microsoft.UI.Composition

A ContainerVisual whose children are flattened into a single layer.

public ref class LayerVisual sealed : ContainerVisual

/// [Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
/// [Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
/// [Windows.Foundation.Metadata.ContractVersion(Microsoft.Foundation.WindowsAppSDKContract, 65536)]
class LayerVisual final : ContainerVisual

[Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
[Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
[Windows.Foundation.Metadata.ContractVersion(typeof(Microsoft.Foundation.WindowsAppSDKContract), 65536)]
public sealed class LayerVisual : ContainerVisual

Public NotInheritable Class LayerVisual
Inherits ContainerVisual

Inheritance

Object Platform::Object IInspectable CompositionObject Visual ContainerVisual LayerVisual

Attributes

ContractVersionAttribute MarshalingBehaviorAttribute ThreadingAttribute

Examples

Apply Effects to a LayerVisual

private async void InitComposition()
{
  Compositor compositor = ElementCompositionPreview.GetElementVisual(MyGrid).Compositor;

  //Create LayerVisual
  LayerVisual layerVisual = compositor.CreateLayerVisual();
  layerVisual.Size = new Vector2(900,900);

  //Create SpriteVisuals to use as LayerVisual child
  SpriteVisual sv1 = compositor.CreateSpriteVisual();
  sv1.Brush = compositor.CreateColorBrush(Windows.UI.Colors.Blue);
  sv1.Size = new Vector2(300, 300);
  sv1.Offset = new Vector3(200, 200, 0);

  SpriteVisual sv2 = compositor.CreateSpriteVisual();
  sv2.Brush = compositor.CreateColorBrush(Colors.Red);
  sv2.Size = new Vector2(300, 300);
  sv2.Offset = new Vector3(400, 400, 0);

  //Add children to the LayerVisual
  layerVisual.Children.InsertAtTop(sv1);
  layerVisual.Children.InsertAtTop(sv2);

  //Create Effect
  var graphicsEffect = new GaussianBlurEffect
  {
     Name = "Blur",
     Source = new CompositionEffectSourceParameter("Backdrop"),
     BlurAmount = 10.0f,
     BorderMode = EffectBorderMode.Hard,
     Optimization = EffectOptimization.Balanced
  };

  var blurEffectFactory = compositor.CreateEffectFactory(graphicsEffect,
      new[] { "Blur.BlurAmount" });
  var blurBrush = blurEffectFactory.CreateBrush();

  //Apply Effect
  layerVisual.Effect = blurBrush;

  ElementCompositionPreview.SetElementChildVisual(MyGrid, layerVisual);
}        

Add a DropShadow

private async void InitComposition()
{
  Compositor compositor = ElementCompositionPreview.GetElementVisual(MyGrid).Compositor;

  //Create LayerVisual
  LayerVisual layerVisual = compositor.CreateLayerVisual();
  layerVisual.Size = new Vector2(900, 900);

  //Create SpriteVisuals to use as LayerVisual child
  SpriteVisual sv1 = compositor.CreateSpriteVisual();
  sv1.Brush = compositor.CreateColorBrush(Windows.UI.Colors.Blue);
  sv1.Size = new Vector2(300, 300);
  sv1.Offset = new Vector3(200, 200, 0);

  SpriteVisual sv2 = compositor.CreateSpriteVisual();
  sv2.Brush = compositor.CreateColorBrush(Colors.Red);
  sv2.Size = new Vector2(300, 300);
  sv2.Offset = new Vector3(400, 400, 0);

  //Add children to the LayerVisual
  layerVisual.Children.InsertAtTop(sv1);
  layerVisual.Children.InsertAtTop(sv2);

  //Create DropShadow
  DropShadow shadow = compositor.CreateDropShadow();
  shadow.Color = Colors.DarkSlateGray;
  shadow.Offset = new Vector3(40, 40, 0);
  shadow.BlurRadius = 9;
  shadow.SourcePolicy = CompositionDropShadowSourcePolicy.InheritFromVisualContent;

  //Associate Shadow with LayerVisual
  layerVisual.Shadow = shadow;

  ElementCompositionPreview.SetElementChildVisual(MyGrid, layerVisual);
}         

Remarks

A LayerVisual is a special input type that can be used to select a tree of visuals. The tree input is implicitly specified using the LayerVisual. When an EffectBrush is set to the Effect property of the LayerVisual, the EffectBrush automatically uses the subtree rooted at the LayerVisual as the input. The implicit input for LayerVisual works for effects as follows:

• If the effect has one input, the EffectBrush uses the subtree rooted at the LayerVisual as the input.
• If the effect has 2 inputs, the first unbounded input of the EffectBrush uses the subtree rooted at the LayerVisual as the input.
• The system does not allow an effect with 0 inputs or effects with all inputs bounded to SurfaceBrush to be set as the EffectBrush on LayerVisual's Effect property. This will throw an exception.

Properties

AnchorPoint	The point on the visual to be positioned at the visual's offset. Value is normalized with respect to the size of the visual. Animatable. (Inherited from Visual)
BackfaceVisibility	Specifies whether the back face of the visual should be visible during a 3D transform. (Inherited from Visual)
BorderMode	Specifies how to compose the edges of bitmaps and clips associated with a visual, or with all visuals in the subtree rooted at this visual. Setting BorderMode at a parent Visual will affect all children visuals in the subtree and can be selectively turned off at each child visual. (Inherited from Visual)
CenterPoint	The point about which rotation or scaling occurs. Animatable (Inherited from Visual)
Children	The children of the ContainerVisual. (Inherited from ContainerVisual)
Clip	Specifies the clipping region for the visual. When a visual is rendered, only the portion of the visual that falls inside the clipping region is displayed, while any content that extends outside the clipping region is clipped (that is, not displayed). (Inherited from Visual)
Comment	A string to associate with the CompositionObject. (Inherited from CompositionObject)
CompositeMode	Specifies how a visual's bitmap is blended with the screen. (Inherited from Visual)
Compositor	The Compositor used to create this CompositionObject. (Inherited from CompositionObject)
DispatcherQueue	Gets the DispatcherQueue for the CompositionObject. (Inherited from CompositionObject)
Effect	The effect to be applied to the flattened representation of the children of a LayerVisual.
ImplicitAnimations	The collection of implicit animations attached to this object. (Inherited from CompositionObject)
IsHitTestVisible	Gets or sets a value that indicates whether the visual sub-tree rooted at this visual participates in hit testing. (Inherited from Visual)
IsPixelSnappingEnabled	Gets or sets a value that indicates whether the composition engine aligns the rendered visual with a pixel boundary. (Inherited from Visual)
IsVisible	Indicates whether the visual and its entire subtree of child visuals is visible. (Inherited from Visual)
Offset	The offset of the visual relative to its parent or for a root visual the offset relative to the upper-left corner of the windows that hosts the visual. Animatable. (Inherited from Visual)
Opacity	The opacity of the visual. Animatable. The opacity property determines the transparency, if any, of the Visual and is a value from 0 to 1. 0 is fully transparent and 1 is full opaque. A Visual with an Opacity property of 0 is still present in the tree. Like other properties on the Visual, Opacity can be animated using the Windows,UI.Composition animation system. (Inherited from Visual)
Orientation	A quaternion describing an orientation and rotation in 3D space that will be applied to the visual. Animatable. (Inherited from Visual)
Parent	The parent of the visual. (Inherited from Visual)
ParentForTransform	Visual specifying the coordinate system in which this visual is composed. (Inherited from Visual)
Properties	The collection of properties associated with the CompositionObject. (Inherited from CompositionObject)
RelativeOffsetAdjustment	Specifies the offset of the visual with respect to the size of its parent visual. (Inherited from Visual)
RelativeSizeAdjustment	Gets or sets the size of the visual with respect to the size of its parent visual. (Inherited from Visual)
RotationAngle	The rotation angle in radians of the visual. Animatable. (Inherited from Visual)
RotationAngleInDegrees	The rotation angle of the visual in degrees. Animatable. (Inherited from Visual)
RotationAxis	The axis to rotate the visual around. Animatable. (Inherited from Visual)
Scale	The scale to apply to the visual. (Inherited from Visual)
Shadow	The shadow to be applied to the flattened representation of the children of a LayerVisual.
Size	The width and height of the visual. Animatable. (Inherited from Visual)
TransformMatrix	The transformation matrix to apply to the visual. Animatable. (Inherited from Visual)

Methods

Close()	Closes the CompositionObject and releases system resources. (Inherited from CompositionObject)
Dispose()	Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources. (Inherited from CompositionObject)
PopulatePropertyInfo(String, AnimationPropertyInfo)	Defines a property that can be animated. (Inherited from CompositionObject)
StartAnimation(String, CompositionAnimation, AnimationController)	Connects an animation with the specified property of the object and starts the animation. (Inherited from CompositionObject)
StartAnimation(String, CompositionAnimation)	Connects an animation with the specified property of the object and starts the animation. (Inherited from CompositionObject)
StartAnimationGroup(ICompositionAnimationBase)	Starts an animation group. The StartAnimationGroup method on CompositionObject lets you start CompositionAnimationGroup. All the animations in the group will be started at the same time on the object. (Inherited from CompositionObject)
StopAnimation(String)	Disconnects an animation from the specified property and stops the animation. (Inherited from CompositionObject)
StopAnimationGroup(ICompositionAnimationBase)	Stops an animation group. (Inherited from CompositionObject)
TryGetAnimationController(String)	Returns an AnimationController for the animation running on the specified property. (Inherited from CompositionObject)

See also

• ContainerVisual
• IClosable