CompositionMaskBrush Classe

Definizione

public ref class CompositionMaskBrush sealed : CompositionBrush

/// [Windows.Foundation.Metadata.ContractVersion(Windows.Foundation.UniversalApiContract, 196608)]
/// [Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
/// [Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
class CompositionMaskBrush final : CompositionBrush

[Windows.Foundation.Metadata.ContractVersion(typeof(Windows.Foundation.UniversalApiContract), 196608)]
[Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
[Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
public sealed class CompositionMaskBrush : CompositionBrush

Public NotInheritable Class CompositionMaskBrush
Inherits CompositionBrush

Ereditarietà

Object Platform::Object IInspectable CompositionObject CompositionBrush CompositionMaskBrush

Attributi

ContractVersionAttribute MarshalingBehaviorAttribute ThreadingAttribute

Requisiti Windows

Esempio

Esempio completo: Applicare una maschera da un file di immagine

L'esempio seguente illustra come creare un oggetto CompositionMaskBrush end-to-end, incluso il caricamento dell'immagine mask. Usare un file PNG con un canale alfa: le aree completamente opache della maschera lasciano l'origine visibile, le aree completamente trasparenti lo nascondono e i valori alfa intermedi producono trasparenza parziale. I valori di colore RGB della maschera non controllano l'opacità; un'immagine opaca in bianco e nero non crea una maschera di trasparenza.

// Get the Compositor from a XAML element
Compositor compositor = ElementCompositionPreview.GetElementVisual(myElement).Compositor;

// Create the mask brush
CompositionMaskBrush maskBrush = compositor.CreateMaskBrush();

// Create the source (the content to be masked)
CompositionColorBrush colorBrush = compositor.CreateColorBrush(Colors.Blue);
maskBrush.Source = colorBrush;

// Load a mask image and create a surface brush from it
// The PNG's alpha channel defines the mask (opaque = visible, transparent = hidden)
LoadedImageSurface maskSurface = LoadedImageSurface.StartLoadFromUri(new Uri("ms-appx:///Assets/CircleMask.png"));
CompositionSurfaceBrush maskSurfaceBrush = compositor.CreateSurfaceBrush(maskSurface);
maskBrush.Mask = maskSurfaceBrush;

// Apply to a SpriteVisual and add it to the XAML tree
SpriteVisual visual = compositor.CreateSpriteVisual();
visual.Brush = maskBrush;
visual.Size = new System.Numerics.Vector2(200, 200);
ElementCompositionPreview.SetElementChildVisual(myElement, visual);

Applicare una maschera a forma di stella a un'immagine

Gli esempi seguenti illustrano vari modi per usare CompositionMaskBrush. Ogni esempio riceve istanze ICompositionSurface create in anticipo. È possibile creare queste superfici usando LoadedImageSurface come illustrato nell'esempio precedente o tramite Win2D.

private SpriteVisual CreateCircleImage(ICompositionSurface myImageSurface, ICompositionSurface myStarMaskSurface) 
{ 
  // Create SurfaceBrush with image surface and specify stretch and alignment 
  CompositionSurfaceBrush imageBrush = _compositor.CreateSurfaceBrush(myImageSurface); 
  imageBrush.HorizontalAlignmentRatio = 0.5f; 
  imageBrush.VerticalAlignmentRatio = 0.5f; 
  imageBrush.Stretch = CompositionStretch.UniformToFill; 

  // Create surface brush with opacity mask surface and specify stretch and alignment 
  CompositionSurfaceBrush starMaskBrush = _compositor.CreateSurfaceBrush(myStarMaskSurface); 
  starMaskBrush.Stretch = CompositionStretch.Uniform; 

  // SpriteVisual to be painted with masked content 
  SpriteVisual imageVisual = _compositor.CreateSpriteVisual(); 
  imageVisual.Size = new Vector2(200, 200); 

  // Create MaskBrush 
  CompositionMaskBrush maskBrush = _compositor.CreateMaskBrush(); 
  maskBrush.Source = imageBrush; // Set source to content that is to be masked 
  maskBrush.Mask = starMaskBrush; // Set mask to content that is the opacity mask 

  imageVisual.Brush = maskBrush; // Paint SpriteVisual with MaskBrush 

  return imageVisual;           
} 

Animare una maschera di opacità per creare un effetto di fioritura del colore

private void CreateCircleMaskSprite(ICompositionSurface myCircleMaskSurface, ICompositionSurface myImageSurface)
{
  // SpriteVisual to be painted by MaskBrush
  _circleVisual = _compositor.CreateSpriteVisual();
  _circleVisual.Size = MyContainerGrid.RenderSize.ToVector2();

  // SurfaceBrush w/ image as MaskBrush.Source
  CompositionSurfaceBrush imageBrush = _compositor.CreateSurfaceBrush(myImageSurface);
  imageBrush.Stretch = CompositionStretch.UniformToFill;

  // SurfaceBrush w/ opacity mask surface as MaskBrush.Mask
  CompositionSurfaceBrush circleBrush = _compositor.CreateSurfaceBrush(myCircleMaskSurface);

  // Specify stretch and transform properties to scale and position brush for initial state
  circleBrush.Stretch = CompositionStretch.Uniform;
  circleBrush.CenterPoint = _circleVisual.Size / 2;
  circleBrush.Scale = new Vector2(0.5f);

  // Create MaskBrush
  CompositionMaskBrush maskBrush = _compositor.CreateMaskBrush();
  maskBrush.Source = imageBrush;
  maskBrush.Mask = circleBrush;
  _circleVisual.Brush = maskBrush;

  // Set SpriteVisual as child of XAML Grid
  ElementCompositionPreview.SetElementChildVisual(MyContainerGrid, _circleVisual);
}

private void BloomAnimation()
{
  // Create KeyFrame Animation to target Scale transform on SurfaceBrush 
  Vector2KeyFrameAnimation scaleAnimation = _compositor.CreateVector2KeyFrameAnimation();
  scaleAnimation.InsertKeyFrame(1.0f, new Vector2(2));
  scaleAnimation.Duration = TimeSpan.FromMilliseconds(500);

  var maskBrush = (CompositionMaskBrush)_circleVisual.Brush;
  var surfaceBrush = (CompositionSurfaceBrush) maskBrush.Mask;

  // Animate the Scale on the circle opacity mask
  surfaceBrush.StartAnimation("Scale", scaleAnimation);      
}

Usare una maschera NineGridBrush per un rettangolo arrotondato

private SpriteVisual CreateMaskedRoundedRectVisual(ICompositionSurface myRoundedRectMaskSurface)
{
  // ColorBrush to be set as MaskBrush.Source
  CompositionColorBrush colorBrush = _compositor.CreateColorBrush(Colors.Blue);

  // SurfaceBrush w/ opacity mask surface
  CompositionSurfaceBrush roundedRectBrush = _compositor.CreateSurfaceBrush(myRoundedRectMaskSurface);
  roundedRectBrush.Stretch = CompositionStretch.Fill; // stretch for center of nine-grid

  // NineGridBrush w/ insets on opacity mask surface
  CompositionNineGridBrush ninegridBrush = _compositor.CreateNineGridBrush();
  ninegridBrush.Source = roundedRectBrush;
  ninegridBrush.SetInsets(_cornerRadius); // the radius, in pixels, of the corner as specified on my opacity mask surface 

  // Create MaskBrush
  CompositionMaskBrush maskBrush = _compositor.CreateMaskBrush();
  maskBrush.Source = colorBrush;
  maskBrush.Mask = ninegridBrush;

  // Paint SpriteVisual with MaskBrush
  SpriteVisual sprite = _compositor.CreateSpriteVisual();
  sprite.Size = new Vector2(300, 200);
  sprite.Brush = maskBrush;
  return sprite;

}

Commenti

CompositionMaskBrush non può essere impostato come parametro di origine su compositionEffectBrush. Se vuoi applicare un oggetto IGraphicsEffect al contenuto mascherato, usa invece compositionEffectBrush con l'effetto Composito .

Vedi anche

• CompositionBrush
• IClosable