Avalonia/samples/ControlCatalog/Pages/CanvasPage.xaml

<UserControl xmlns="https://github.com/avaloniaui">
  <StackPanel Orientation="Vertical" Spacing="4">
    <TextBlock Classes="h1">Canvas</TextBlock>
    <TextBlock Classes="h2">A panel which lays out its children by explicit coordinates</TextBlock>
    <Canvas Background="Yellow" Width="300" Height="400">
      <Rectangle Fill="Blue" Width="63" Height="41" Canvas.Left="40" Canvas.Top="31">
        <Rectangle.OpacityMask>
          <LinearGradientBrush StartPoint="0%,0%" EndPoint="100%,100%">
            <LinearGradientBrush.GradientStops>
              <GradientStop Offset="0" Color="Black"/>
              <GradientStop Offset="1" Color="Transparent"/>
            </LinearGradientBrush.GradientStops>
          </LinearGradientBrush>
        </Rectangle.OpacityMask>     
      </Rectangle>
      <Ellipse Fill="Green" Width="58" Height="58" Canvas.Left="88" Canvas.Top="100"/>
      <Path Fill="Orange" Data="M 0,0 c 0,0 50,0 50,-50 c 0,0 50,0 50,50 h -50 v 50 l -50,-50 Z" Canvas.Left="30" Canvas.Top="250"/>
      <Path Fill="OrangeRed" Canvas.Left="180" Canvas.Top="250">
        <Path.Data>
          <PathGeometry>
            <PathFigure StartPoint="0,0" IsClosed="True">
              <QuadraticBezierSegment Point1="50,0" Point2="50,-50" />
              <QuadraticBezierSegment Point1="100,-50" Point2="100,0" />
              <LineSegment Point="50,0" />
              <LineSegment Point="50,50" />
            </PathFigure>
          </PathGeometry>
        </Path.Data>
      </Path>
      <Line StartPoint="120,185" EndPoint="30,115" Stroke="Red" StrokeThickness="2"/>
      <Polygon Points="75,0 120,120 0,45 150,45 30,120" Stroke="DarkBlue" StrokeThickness="1" Fill="Violet" Canvas.Left="150" Canvas.Top="31"/>
      <Polyline Points="0,0 65,0 78,-26 91,39 104,-39 117,13 130,0 195,0" Stroke="Brown" Canvas.Left="30" Canvas.Top="350"/>
    </Canvas>
  </StackPanel>
</UserControl>