Okay, I'll retract my question, I was buildung the Path wrongly. This is how it should be done:
var path = new PathF();
path.MoveTo(topLeft);
path.LineTo(topRight);
path.LineTo(bottomCenter);
path.Close();
ICanvas.DrawPath / ICanvas.FillPath ArgumentException
Tim W
31
Reputation points
I am trying draw a filled polygon using IDrawable and PathF. I am getting an ArgumentException on canvas.FillPath or canvas.DrawPath, stating that "A call to CanvasPathBuilder.BeginFigure occurred, when the figure was already begun.". I am not sure what I am doing wrong. Does anybody have an idea? Here is a reproductive source that should draw / fill a triangle (you can reproduce it by copy / pasting this in the MainPage.xaml.cs of a new Maui project):
namespace CanvasPath
{
public partial class MainPage : ContentPage, IDrawable
{
public MainPage()
{
this.Content = new GraphicsView { Drawable = this };
}
public void Draw(ICanvas canvas, RectF dirtyRect)
{
canvas.StrokeColor = Colors.Green;
canvas.FillColor = Colors.Red;
var topLeft = new PointF(dirtyRect.Left, dirtyRect.Top);
var topRight = new PointF(dirtyRect.Right, dirtyRect.Top);
var bottomCenter = new PointF(dirtyRect.Center.X, dirtyRect.Bottom);
canvas.DrawCircle(topLeft, 10);
canvas.DrawCircle(topRight, 10);
canvas.DrawCircle(bottomCenter, 10);
var path = new PathF(topLeft);
path.MoveTo(bottomCenter);
path.MoveTo(topRight);
path.Close();
//both calls do nothing on Android, but throw an ArgumentException on Windows
canvas.DrawPath(path);
canvas.FillPath(path);
}
private void OnCounterClicked(object sender, EventArgs e)
{
}
}
}
1 answer
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Tim W 31 Reputation points
2022-06-26T12:13:45.51+00:00