UWP Composition 是否有非 Win2D 文本解决方案 API

Question

为了避免 XY 问题，首先是 Y：有没有办法在不需要 Win2D 的 SpriteVisual 上创建文本？

现在 X：我要解决的问题是我需要 SpriteVisual（而不是 TextBlock）上的文本来应用透视旋转 3D 表达式动画。 SpriteVisual 上的文本可以使用 Win2D 完成。这是 Microsoft sample code:

的一部分

using (var ds = CanvasComposition.CreateDrawingSession(_drawingSurface))
{
     ds.Clear(Colors.Transparent);
     var rect = new Rect(new Point(2, 2), (_drawingSurface.Size.ToVector2() - new Vector2(4, 4)).ToSize());
     ds.FillRoundedRectangle(rect, 15, 15, Colors.LightBlue);
     ds.DrawRoundedRectangle(rect, 15, 15, Colors.Gray, 2);
     ds.DrawText("This is a composition drawing surface", rect, Colors.Black, new CanvasTextFormat()
     {
          FontFamily = "Comic Sans MS",
          FontSize = 32,
          WordWrapping = CanvasWordWrapping.WholeWord,
          VerticalAlignment = CanvasVerticalAlignment.Center,
          HorizontalAlignment = CanvasHorizontalAlignment.Center
     }
);

_drawingBrush.Surface = _drawingSurface;

_drawingVisual = _compositor.CreateSpriteVisual();
_drawingVisual.Brush = _drawingBrush;

要为其中的文本着色需要 Win2D ICanvasBrush。但我想在 Expression Animation 中为颜色设置动画，因此我需要来自 CompositionBrush 的文本颜色。现在我可以创建一个 CompositionMaskBrush，其中文本画笔作为遮罩，CompositionBrush 作为源。但是对于 CompositionMaskBrush，我无法为其添加额外的遮罩或任何其他合成效果，这对我来说是个问题。

是否有我不熟悉的 Insider Build 中的替代方法或增强组合 API？

Answer 1

Y-answer：不能，您只能使用 Win2d CanvasDrawingSession 在 CompositionDrawingSurface 上绘制文本。但是您可以使用 ElementCompositionPreview.GetElementVisual(yourTextBlock) 从 XAML TextBlock 获得 Visual 并使用 Composition API 表达式 + XAML 颜色故事板对其进行动画处理。

X-answer：您可以从文本 CompositionDrawingSurface 创建一个 alpha 蒙版并将其应用于 CompositionColorBrush:

    private void CreateColoredText(string text)
    {
        var compositor = ElementCompositionPreview.GetElementVisual(this).Compositor;
        var graphicsDevice = CanvasComposition.CreateCompositionGraphicsDevice(compositor, CanvasDevice.GetSharedDevice());

        var spriteTextVisual = compositor.CreateSpriteVisual();
        spriteTextVisual.Size = new Vector2(512, 512);

        var maskDrawingSurface = graphicsDevice.CreateDrawingSurface(new Size(512, 512), DirectXPixelFormat.B8G8R8A8UIntNormalized, DirectXAlphaMode.Premultiplied);

        using (var ds = CanvasComposition.CreateDrawingSession(maskDrawingSurface))
        {
            ds.Clear(Colors.Transparent);
            ds.DrawText(text, new Rect(0, 0, 512, 512), Colors.Lime, new CanvasTextFormat
            {
                FontSize = 32,
                FontWeight = FontWeights.Bold,
                VerticalAlignment = CanvasVerticalAlignment.Center,
                HorizontalAlignment = CanvasHorizontalAlignment.Center,
                LineSpacing = 32
            });
        }

        var maskSurfaceBrush = compositor.CreateSurfaceBrush(maskDrawingSurface);
        var surfaceTextBrush = compositor.CreateColorBrush(Colors.DeepPink);
        var maskBrush = compositor.CreateMaskBrush();
        maskBrush.Mask = maskSurfaceBrush;
        maskBrush.Source = surfaceTextBrush;

        var colorAnimation = compositor.CreateColorKeyFrameAnimation();
        colorAnimation.InsertKeyFrame(0.5f, Colors.DeepSkyBlue);
        colorAnimation.InsertKeyFrame(1, Colors.DeepPink);
        colorAnimation.Duration = TimeSpan.FromMilliseconds(1500);
        colorAnimation.IterationBehavior = AnimationIterationBehavior.Forever;

        surfaceTextBrush.StartAnimation("Color", colorAnimation);

        spriteTextVisual.Brush = maskBrush;

        ElementCompositionPreview.SetElementChildVisual(Grid, spriteTextVisual);
    }

现在您可以为您的目的设置颜色和透视动画。

UWP Composition 是否有非 Win2D 文本解决方案 API

Is There a Non-Win2D Text Solution for UWP Composition API

uwp

windows-runtime

win2d