WPF:如何绘制这个多边形？

Question

我想绘制以下红色多边形:

问题是如果我使用这样的东西:

Polygon poly = new Polygon();
poly.StrokeThickness = 2;
poly.Stroke = Brushes.Black;
PointCollection points = new PointCollection();

for (int i = 0; i < this.NumberOfMetrics; i++)
{
   points.Add(new Point(MAX_VALUE - this.Metrics[n, i] * Math.Cos(DegreeToRadian(i * (360 / (this.NumberOfMetrics)))), MAX_Y_GUI - this.Metrics[n, i] * Math.Sin(DegreeToRadian(i * (360 / (this.NumberOfMetrics))))));
}       
poly.Points = points;

然后多边形总是"填充",并且在上面的示例中绘制红色和绿色多边形.

我已经尝试将4个"内部"点添加到PointCollection中,但之后没有绘制任何内容.那我怎么能实现呢？

我尝试了大卫提出的解决方案:

for (int n = 0; n < this.NumberOfRevisions; n++)
            {
                Path path = new Path();

                CombinedGeometry geometry = new CombinedGeometry();
                geometry.GeometryCombineMode = GeometryCombineMode.Union;

                Polygon poly = new Polygon();
                PointCollection points = new PointCollection();

                for (int i = 0; i < this.NumberOfMetrics; i++)
                {
                    points.Add(new Point(MAX_VALUE - this.Metrics[n, i] * Math.Cos(DegreeToRadian(i * (360 / (this.NumberOfMetrics)))), MAX_Y_GUI - this.Metrics[n, i] * Math.Sin(DegreeToRadian(i * (360 / (this.NumberOfMetrics))))));
                }

                poly.Points = points;

                geometry.Geometry1 = poly.RenderedGeometry;


                geometry.Geometry2 = poly.RenderedGeometry;


                path.Data = geometry;

                polygons.Add(poly);

                paths.Add(path);
            }

这只是一个测试,但我知道所以我应该得到与以前相同的结果,但它没有被绘制.我的代码有问题吗？

Answer 1

如果您想拥有2个独立的形状,并且绿色的形状可能是您在评论中所说的透明,那么最好的方法是使用组合几何:

http://msdn.microsoft.com/en-en/library/ms653071%28v=VS.85%29.aspx

借助于此,您可以先创建绿色几何体,然后通过从红色几何体中减去绿色(或其副本)来创建孔.

所以基本上:

1. 红色的形状,平原
2. 在它上面的绿色形状,平原
3. 从红色形状中划出绿色形状或其副本>>红色形状的孔

这样你就可以得到你想要的效果

在Xaml中更容易完成,在C#中有点复杂,但仍然可行.

编辑:将Combined Geometry设置为Path的数据:

Path myPath = new Path();
CombinedGeometry myCombinedGeometry = new CombinedGeometry()

// here you set the combinedGeometry's geometries to create the shape you want

myPath.Data = myCombinedGeometry;

myGrid.Children.Add(myPath);

顺便说一下,PATH将是您为颜色设置Fill/Stroke属性的位置,而不是内部几何.(请参阅上面链接中的xaml中的示例,您基本上只需要将代码转换为C#)

EDIT2:

不要忘记在路径上设置填充:

for (int n = 0; n < this.NumberOfRevisions; n++)
{
    CombinedGeometry geometry = new CombinedGeometry() { GeometryCombineMode = GeometryCombineMode.Union };

    PointCollection points = new PointCollection();

    for (int i = 0; i < this.NumberOfMetrics; i++)
    {
        points.Add(new Point(MAX_VALUE - this.Metrics[n, i] * Math.Cos(DegreeToRadian(i * (360 / (this.NumberOfMetrics)))), MAX_Y_GUI - this.Metrics[n, i] * Math.Sin(DegreeToRadian(i * (360 / (this.NumberOfMetrics))))));
    }

    Polygon poly = new Polygon();
    poly.Points = points;

    geometry.Geometry1 = poly.RenderedGeometry;
    geometry.Geometry2 = poly.RenderedGeometry;

    polygons.Add(poly);

    paths.Add(path = new Path() { Data = geometry, Fill = Brushes.Red, Stroke = Brushes.Transparent });
}