ArcSegment 的旋转和方向答案

【问题标题】：Rotation and Direction of ArcSegmentArcSegment 的旋转和方向
【发布时间】：2011-07-02 07:59:02
【问题描述】：

有没有办法让 ArcSegment 朝特定方向绘制？据我所知，它总是从上到下绘制。例如，我有一个 ArcSegment，它开始在 180 度（270 度是北）并绘制一个几乎椭圆到 180 度。现在，绘图是顺时针方向的......好吧，对不起，让我告诉你。

左侧是我从一组转换值中收到的值，但我需要它像右侧一样。

<Canvas Background="#FDB" Width="720" Height="540">
  <Path Canvas.Left="100" Canvas.Top="100" Stroke="#385D8A" StrokeThickness="2" StrokeLineJoin="Round" Fill="#4F81BD">
    <!-- this is the LEFT shape that I need drawn like the other one -->
    <Path.Data>
      <GeometryGroup>
        <PathGeometry>
          <PathGeometry.Figures>
            <PathFigure StartPoint="0,51" IsClosed="True">
              <PathFigure.Segments>
                <LineSegment Point="51,51" />
              </PathFigure.Segments>
            </PathFigure>
            <PathFigure StartPoint="25.5,0">
              <PathFigure.Segments>
                <LineSegment Point="25.5,102" />
              </PathFigure.Segments>
            </PathFigure>
            <PathFigure StartPoint="25.5,51" IsClosed="True" >
              <PathFigure.Segments>
                <ArcSegment Size="25.5,25.5" IsLargeArc="True" SweepDirection="Clockwise" Point="25.49,51" />
              </PathFigure.Segments>
            </PathFigure>
          </PathGeometry.Figures>
        </PathGeometry>
      </GeometryGroup>
    </Path.Data>
  </Path>
  <Path Canvas.Left="200" Canvas.Top="100" Stroke="#385D8A" StrokeThickness="2" StrokeLineJoin="Round" Fill="#4F81BD">
    <!-- this is the RIGHT shape, the way it should behave, but notice the different StartPoint and Point -->
    <Path.Data>
      <GeometryGroup>
        <PathGeometry>
          <PathGeometry.Figures>
            <PathFigure StartPoint="0,51" IsClosed="True">
              <PathFigure.Segments>
                <LineSegment Point="51,51" />
              </PathFigure.Segments>
            </PathFigure>
            <PathFigure StartPoint="25.5,0">
              <PathFigure.Segments>
                <LineSegment Point="25.5,102" />
              </PathFigure.Segments>
            </PathFigure>
            <PathFigure StartPoint="51,25.5" IsClosed="True" >
              <PathFigure.Segments>
                <ArcSegment Size="25.5,25.5" IsLargeArc="True" SweepDirection="Clockwise" Point="50.99,25.5" />
              </PathFigure.Segments>
            </PathFigure>
          </PathGeometry.Figures>
        </PathGeometry>
      </GeometryGroup>
    </Path.Data>
  </Path>
</Canvas>

我试过玩弄RotationAngle，但这似乎没有任何效果，因为它只适用于 X 轴，而不适用于 Y 轴。

第一个Path的值来自一个转换例程，所以我不能轻易修改它们。

【问题讨论】：

标签： wpf silverlight geometric-arc pathgeometry

【解决方案1】：

我想我已经弄清楚了 - 只需缩短 Y 轴而不是 X 轴。所以：

<PathFigure StartPoint="51,25.5" IsClosed="True" >
    <PathFigure.Segments>
        <ArcSegment Point="50.99,25.5" Size="25.5,25.5" IsLargeArc="True" SweepDirection="Clockwise"  />
    </PathFigure.Segments>
</PathFigure>

应该是：

<PathFigure StartPoint="51,25.5" IsClosed="True" >
    <PathFigure.Segments>
        <ArcSegment Point="51,24.99" Size="25.5,25.5" IsLargeArc="True" SweepDirection="Clockwise"  />
    </PathFigure.Segments>
</PathFigure>

就这么简单。

【讨论】：