C# 使UIElement仅在聚光灯下可见
我有一个矩形:C# 使UIElement仅在聚光灯下可见,c#,xaml,uwp,win2d,xaml-composition,C#,Xaml,Uwp,Win2d,Xaml Composition,我有一个矩形: <Border x:Name="Elem1" BorderThickness="2" Height="100" Width="200" BorderBrush="Red" /> 当rectagle上没有灯光时,它将保持黑色: 我希望矩形的其余部分是透明的,因此只有被照亮的部分才可见 我尝试添加透明AmblentLight,但忽略了aplha通道 我想这可以通过场景照明效果来实现,但如何实现呢?:) 特别为你准备的:D public MainPage()
<Border x:Name="Elem1" BorderThickness="2" Height="100" Width="200" BorderBrush="Red" />
当rectagle上没有灯光时,它将保持黑色:
我希望矩形的其余部分是透明的,因此只有被照亮的部分才可见
我尝试添加透明AmblentLight,但忽略了aplha通道
我想这可以通过场景照明效果来实现,但如何实现呢?:) 特别为你准备的:D
public MainPage()
{
InitializeComponent();
Loaded += MainPage_Loaded;
}
private CompositionSurfaceBrush _maskSurfaceBrush;
private readonly float _size = 512;
private async void MainPage_Loaded(object sender, RoutedEventArgs e)
{
PointerMoved += MainPage_PointerMoved;
var compositor = ElementCompositionPreview.GetElementVisual(this).Compositor;
var canvasDevice = CanvasDevice.GetSharedDevice();
var graphicsDevice = CanvasComposition.CreateCompositionGraphicsDevice(compositor, canvasDevice);
var canvasBitmap = await CanvasBitmap.LoadAsync(canvasDevice, new Uri("ms-appx:///Assets/44578.jpg"));
var sourceDrawingSurface = graphicsDevice.CreateDrawingSurface(new Size(_size, _size), DirectXPixelFormat.B8G8R8A8UIntNormalized, DirectXAlphaMode.Premultiplied);
using (var ds = CanvasComposition.CreateDrawingSession(sourceDrawingSurface))
{
ds.Clear(Colors.Transparent);
ds.DrawImage(canvasBitmap);
}
var sourceSurfaceBrush = compositor.CreateSurfaceBrush(sourceDrawingSurface);
var maskRenderTarget = new CanvasRenderTarget(canvasDevice, _size, _size, 96);
using (var ds = maskRenderTarget.CreateDrawingSession())
{
ds.Clear(Colors.Transparent);
ds.FillCircle(_size / 2, _size / 2, _size / 8, Colors.Black);
}
var blur = new GaussianBlurEffect
{
BlurAmount = 16,
Source = maskRenderTarget
};
var blurredMaskDrawingSurface = graphicsDevice.CreateDrawingSurface(new Size(_size, _size), DirectXPixelFormat.B8G8R8A8UIntNormalized, DirectXAlphaMode.Premultiplied);
using (var ds = CanvasComposition.CreateDrawingSession(blurredMaskDrawingSurface))
{
ds.Clear(Colors.Transparent);
ds.DrawImage(blur);
}
_maskSurfaceBrush = compositor.CreateSurfaceBrush(blurredMaskDrawingSurface);
var composite = new CompositeEffect
{
Sources = { new CompositionEffectSourceParameter("source"), new CompositionEffectSourceParameter("mask") },
Mode = CanvasComposite.DestinationAtop
};
var effectFactory = compositor.CreateEffectFactory(composite);
var fxBrush = effectFactory.CreateBrush();
fxBrush.SetSourceParameter("source", sourceSurfaceBrush);
fxBrush.SetSourceParameter("mask", _maskSurfaceBrush);
var sprite = compositor.CreateSpriteVisual();
sprite.Size = new Vector2(_size, _size);
sprite.Brush = fxBrush;
ElementCompositionPreview.SetElementChildVisual(this, sprite);
}
private void MainPage_PointerMoved(object sender, PointerRoutedEventArgs e)
{
var position = e.GetCurrentPoint(this).Position.ToVector2();
_maskSurfaceBrush.Offset = position - new Vector2(_size / 2, _size / 2);
}
比以往任何时候都好 如果适合你的情况,你可以用面具代替聚光灯。我也试过,但没有成功。不是因为这不可能,而是因为我对uwp的知识有限,我不知道如何创建径向梯度掩模并移动它
public MainPage()
{
InitializeComponent();
Loaded += MainPage_Loaded;
}
private CompositionSurfaceBrush _maskSurfaceBrush;
private readonly float _size = 512;
private async void MainPage_Loaded(object sender, RoutedEventArgs e)
{
PointerMoved += MainPage_PointerMoved;
var compositor = ElementCompositionPreview.GetElementVisual(this).Compositor;
var canvasDevice = CanvasDevice.GetSharedDevice();
var graphicsDevice = CanvasComposition.CreateCompositionGraphicsDevice(compositor, canvasDevice);
var canvasBitmap = await CanvasBitmap.LoadAsync(canvasDevice, new Uri("ms-appx:///Assets/44578.jpg"));
var sourceDrawingSurface = graphicsDevice.CreateDrawingSurface(new Size(_size, _size), DirectXPixelFormat.B8G8R8A8UIntNormalized, DirectXAlphaMode.Premultiplied);
using (var ds = CanvasComposition.CreateDrawingSession(sourceDrawingSurface))
{
ds.Clear(Colors.Transparent);
ds.DrawImage(canvasBitmap);
}
var sourceSurfaceBrush = compositor.CreateSurfaceBrush(sourceDrawingSurface);
var maskRenderTarget = new CanvasRenderTarget(canvasDevice, _size, _size, 96);
using (var ds = maskRenderTarget.CreateDrawingSession())
{
ds.Clear(Colors.Transparent);
ds.FillCircle(_size / 2, _size / 2, _size / 8, Colors.Black);
}
var blur = new GaussianBlurEffect
{
BlurAmount = 16,
Source = maskRenderTarget
};
var blurredMaskDrawingSurface = graphicsDevice.CreateDrawingSurface(new Size(_size, _size), DirectXPixelFormat.B8G8R8A8UIntNormalized, DirectXAlphaMode.Premultiplied);
using (var ds = CanvasComposition.CreateDrawingSession(blurredMaskDrawingSurface))
{
ds.Clear(Colors.Transparent);
ds.DrawImage(blur);
}
_maskSurfaceBrush = compositor.CreateSurfaceBrush(blurredMaskDrawingSurface);
var composite = new CompositeEffect
{
Sources = { new CompositionEffectSourceParameter("source"), new CompositionEffectSourceParameter("mask") },
Mode = CanvasComposite.DestinationAtop
};
var effectFactory = compositor.CreateEffectFactory(composite);
var fxBrush = effectFactory.CreateBrush();
fxBrush.SetSourceParameter("source", sourceSurfaceBrush);
fxBrush.SetSourceParameter("mask", _maskSurfaceBrush);
var sprite = compositor.CreateSpriteVisual();
sprite.Size = new Vector2(_size, _size);
sprite.Brush = fxBrush;
ElementCompositionPreview.SetElementChildVisual(this, sprite);
}
private void MainPage_PointerMoved(object sender, PointerRoutedEventArgs e)
{
var position = e.GetCurrentPoint(this).Position.ToVector2();
_maskSurfaceBrush.Offset = position - new Vector2(_size / 2, _size / 2);
}