Question: How to use CompositionPathGeometry and CompositionPath?

Hello,

I try to use CompositionPathGeometry like this:

IGeometrySource2D source = <...>
var pathGeometry = Compositor.CreatePathGeometry(new CompositionPath(source));

But I can’t find how to create the source (IGeometrySource2D).

Can you create an example?

[castorix]

With Windows.UI.Composition, it is done with IGeometrySource2DInterop, like in https://github.com/microsoft/Windows.UI.Composition-Win32-Samples/blob/master/cpp/HelloVectors/HelloVectors_win32.cpp, but not sure if it works with Microsoft.UI.Composition (I could only test in C# and I got 0x80070057 like @tom-huntington )

[ChewWorker]

I haven’t had a chance to try raw D2D, but it can be done with Win2D. The following example works to use Win2D to build the geometry source. One possible issue with the code you pasted is that there aren’t open/add geometry/close steps being done before creating the composition path. It’s possible the d2d object defaults to a bad/closed state unless the geometry has beeen created. This code was used in a basic UWP/Win2D project:

        var c = Window.Current.Compositor;

        // CanvasGeometry and CanvasPathBuilder are Win2D objects
        CanvasPathBuilder pathBuilder = new CanvasPathBuilder(sender);
        pathBuilder.BeginFigure(1, 1);
        pathBuilder.AddLine(300, 300);
        pathBuilder.AddLine(1, 300);
        pathBuilder.EndFigure(CanvasFigureLoop.Closed);

        CanvasGeometry geometry = CanvasGeometry.CreatePath(pathBuilder);

        // These are Composition Path objects
        var pathGeometry = c.CreatePathGeometry(new CompositionPath(geometry));

        // Need to create a sprite shape from the rounded rect
        var roundedRectSpriteShape              = c.CreateSpriteShape(pathGeometry);
        roundedRectSpriteShape.FillBrush        = c.CreateColorBrush(Colors.Red);

        _shapeContainer.Shapes.Add(roundedRectSpriteShape);