Add polygon/ellipse to inkcanvas in uwp

问题

I'm using Windows-universal-samples-master\Samples\InkAnalysis\InkAnalysis.sln of Microsoft's open source project. It can analysis the shape you draw, and convert to polygon or ellipse.

<Grid
<Canvas x:Name="canvas"/>
<InkCanvas x:Name="inkCanvas"/>
</Grid>

All the converted shapes are drawn to "canvas", not "inkCanvas", so they can not be saved as ink.

How to add the shapes to "inkCanvas"?

回答1:

We can use InkStrokeContainer.AddStroke to add to an InkStroke object to the collection managed by the InkStrokeContainer. If the shape is polygon, We can get the point from the InkAnalysisInkDrawing.Points and set them to the InkStrokeBuilder by the CreateStrokeFromInkPoints method.

For example:

private void AddPolygonToInkCanvas(InkAnalysisInkDrawing shape)
{
    var strokeBuilder = new InkStrokeBuilder();
    var strokes = inkCanvas.InkPresenter.StrokeContainer.GetStrokes();
    strokeBuilder.SetDefaultDrawingAttributes(strokes[0].DrawingAttributes);
    System.Numerics.Matrix3x2 matr = strokes[0].PointTransform;
    List<InkPoint> inkPointslist = new List<InkPoint>();
    foreach (var item in shape.Points)
    {
        var intpoint = new InkPoint(new Point(item.X, item.Y), 0.5f);
        inkPointslist.Add(intpoint);
    }
    var lastintpoint = new InkPoint(new Point(shape.Points[0].X, shape.Points[0].Y), 0.5f);
    inkPointslist.Add(lastintpoint);
    IReadOnlyList<InkPoint> inkPoints = inkPointslist;
    InkStroke stroke = strokeBuilder.CreateStrokeFromInkPoints(inkPoints, matr);  
    inkCanvas.InkPresenter.StrokeContainer.AddStroke(stroke);
}

If the shape is ellipse, as far as I known we can not add it to the InkCanvas. We can not get the all of the ellipse, it only provides 4 points.

来源：https://stackoverflow.com/questions/46784818/add-polygon-ellipse-to-inkcanvas-in-uwp