StreamGeometry.ClearValue () should be how to call?

[fhhyyp]

// this is override "Render()" method
// display a bezier-line on canvas and follow the mouse in real time
// I don't want to re-instantiate StreamGeometry()
// because I want to reduce the number of GC
// but , it seems impossible to do so in avalonia
streamGeometry = new StreamGeometry();
// in wpf , this method allows display content to be cleared
streamGeometry.Clear(); // this is wpf method
// in avalonia, why does this method need value of "AvaloniaProperty" data type ?
// but I don't know use what "AvaloniaProperty" to clear the displayed content
// if I don't clear the cache or re-instantiate it
// the canvas will display repeated lines , because exits cache inside streamGeometry
streamGeometry.ClearValue("AvaloniaProperty");
using (var context = streamGeometry.Open())
{
context.BeginFigure(start, true); // start point of the bezier-line
context.CubicBezierTo(c0, c1, end, true); // drawing bezier-line
}
drawingContext.DrawGeometry(null, visualPen, streamGeometry);

[msneijders]

The ClearValue(AvaloniaProperty) your refer to is of StreamGeometry's base type AvaloniaObject, and is to clear its AvaloniaProperties; not to clear its internal geometry data (is not an avaloniaproperty) -- a StreamGeometry only has TransformProperty you could ClearValue. It looks like a StreamGeometry geometry data cannot be changed or cleared after creating it.

[msneijders]

If you think you do need to optimize for your use case:

• There is GeometryGroup to look at; a composition of multiple geometries -- although with cubic bezier lines, that could break up your lines I guess, or breaking up your cubicbezier lines in multiple segments might give you a good enough result.
• You could look at custom rendering, so you have full control over SKPath and reuse it (assuming you use skia rendering); to get started look at avalonia's samples/RenderDemo.

[fhhyyp]

Thank you so much for your detailed answer! Your suggestions have been incredibly helpful, and I’ll try them out. If I have more questions, I might reach out to you again. 🙏