Pennello solo parti di un Ellipse in WPF

Question

Ho difficoltà a trovare il modo migliore per disegnare la forma sottostante. Sto usando il codice qui sotto per disegnare un Ellipse sul livello visivo.

Ma come posso solo spazzolare i quarti? Penso che si possa fare usando LinearGradientBrush o RadialGradientBrush ma non so come usarlo.

var cntrpoint = space.FlipYAxis(x2, y2); 
dc.DrawEllipse(Brushes.Transparent, pen, cntrpoint, 30, 30); 

Answer 1

Ti piace questa:

var geometry = new GeometryGroup(); 
geometry.Children.Add(new RectangleGeometry(new Rect(1, 0, 1, 1))); 
geometry.Children.Add(new RectangleGeometry(new Rect(0, 1, 1, 1))); 
var drawing = new GeometryDrawing(Brushes.Black, null, geometry); 
var brush = new DrawingBrush(drawing); 

dc.DrawEllipse(brush, pen, cntrpoint, 30, 30); 

Answer 2

ho trovato una soluzione per farlo in XAML
(ispirata a questo post: https://stackoverflow.com/a/5670388/3047078):

<Image Width="200" Height="200" Margin="20"> 
    <Image.Source> 
    <DrawingImage> 
     <DrawingImage.Drawing> 
     <DrawingGroup> 

      <GeometryDrawing Brush="Black"> 
      <GeometryDrawing.Pen> 
       <Pen Brush="Black" /> 
      </GeometryDrawing.Pen> 
      <GeometryDrawing.Geometry> 
       <PathGeometry> 
       <PathFigure StartPoint="100,100"> 
        <PathFigure.Segments> 
        <LineSegment Point="100,0"/> 
        <ArcSegment Point="200,100" SweepDirection="Clockwise" Size="100,100"/> 
        <LineSegment Point="100,100"/> 
        </PathFigure.Segments> 
       </PathFigure> 
       </PathGeometry> 
      </GeometryDrawing.Geometry> 
      </GeometryDrawing> 

      <GeometryDrawing Brush="White"> 
      <GeometryDrawing.Pen> 
       <Pen Brush="Black"/> 
      </GeometryDrawing.Pen> 
      <GeometryDrawing.Geometry> 
       <PathGeometry> 
       <PathFigure StartPoint="200,100"> 
        <PathFigure.Segments> 
        <ArcSegment Point="100,200" SweepDirection="Clockwise" Size="100,100"/> 
        <LineSegment Point="100,100"/> 
        </PathFigure.Segments> 
       </PathFigure> 
       </PathGeometry> 
      </GeometryDrawing.Geometry> 
      </GeometryDrawing> 

      <GeometryDrawing Brush="Black"> 
      <GeometryDrawing.Pen> 
       <Pen Brush="Black"/> 
      </GeometryDrawing.Pen> 
      <GeometryDrawing.Geometry> 
       <PathGeometry> 
       <PathFigure StartPoint="100,100"> 
        <PathFigure.Segments> 
        <LineSegment Point="100,200"/> 
        <ArcSegment Point="0,100" SweepDirection="Clockwise" Size="100,100"/> 
        <LineSegment Point="100,100"/> 
        </PathFigure.Segments> 
       </PathFigure> 
       </PathGeometry> 
      </GeometryDrawing.Geometry> 
      </GeometryDrawing> 

      <GeometryDrawing Brush="White"> 
      <GeometryDrawing.Pen> 
       <Pen Brush="Black"/> 
      </GeometryDrawing.Pen> 
      <GeometryDrawing.Geometry> 
       <PathGeometry> 
       <PathFigure StartPoint="100,100"> 
        <PathFigure.Segments> 
        <LineSegment Point="0,100"/> 
        <ArcSegment Point="100,0" SweepDirection="Clockwise" Size="100,100"/> 
        </PathFigure.Segments> 
       </PathFigure> 
       </PathGeometry> 
      </GeometryDrawing.Geometry> 
      </GeometryDrawing> 

     </DrawingGroup> 
     </DrawingImage.Drawing> 
    </DrawingImage> 
    </Image.Source> 
</Image> 

Answer 3

È possibile eseguire questa operazione utilizzando DrawingBrush e GeometryDrawing

<Ellipse Width="300" Height="300" Stroke="DarkGray" StrokeThickness="1.5"> 
    <Ellipse.Fill> 
     <DrawingBrush> 
      <DrawingBrush.Drawing> 
       <GeometryDrawing> 
        <GeometryDrawing.Brush> 
         <RadialGradientBrush> 
          <GradientStop Color="Black" Offset="1.0" /> 
          <GradientStop Color="White" Offset="1.0" /> 
         </RadialGradientBrush> 
        </GeometryDrawing.Brush> 
        <GeometryDrawing.Geometry> 
         <GeometryGroup> 
          <RectangleGeometry Rect="0,0,50,50" /> 
          <RectangleGeometry Rect="50,50,50,50" /> 
         </GeometryGroup> 
        </GeometryDrawing.Geometry> 
       </GeometryDrawing> 
      </DrawingBrush.Drawing> 
     </DrawingBrush> 
    </Ellipse.Fill> 
</Ellipse> 

uscita: