PathFigure表示几何图形的一个子部分、一系列单独连接的二维几何线段。

以StartPoint为原点，画坐标轴，Y轴箭头向下；按顺序画图。StartPoint原点始终在控件左上角，当其他点的坐标值比原点的值小，原点会偏移。 

通常为： ArcSegment 、BezierSegment, LineSegment, PolyBezierSegment, PolyLineSegment, PolyQuadraticBezierSegment, QuadraticBezierSegment.

例子1：

 <Path Grid.Row="0" x:Name="pathLeft" Fill="LightSkyBlue" Stretch="Fill"

HorizontalAlignment="Left" VerticalAlignment="Bottom">

<Path.Data>

<PathGeometry>

<PathFigure StartPoint="0,40">

<PathSegmentCollection>

<LineSegment Point="100,30" />

<LineSegment Point="100,60" />

</PathSegmentCollection>

</PathFigure>

</PathGeometry>

</Path.Data>

</Path>

例子2：（（0,0）为控件的左上角坐标）

<Path Grid.Row="0" x:Name="pathLeft" Fill="LightSkyBlue" Stretch="Fill"

HorizontalAlignment="Left" VerticalAlignment="Bottom">

<Path.Data>

<PathGeometry>

<PathFigure StartPoint="0,0" >

<PathSegmentCollection>

<LineSegment Point="0,60" />

<LineSegment Point="100,40" />

<LineSegment Point="100,80" />

<LineSegment Point="0,60" />

</PathSegmentCollection>

</PathFigure>

</PathGeometry>

</Path.Data>

</Path>

例子3：

<Path Grid.Row="0" x:Name="pathLeft" Fill="LightSkyBlue" Stretch="Fill"

HorizontalAlignment="Left" VerticalAlignment="Bottom">

<Path.Data>

<PathGeometry>

<PathFigure StartPoint="0,0" >

<PathSegmentCollection>

<LineSegment Point="0,60" />

<LineSegment Point="100,40" />

<LineSegment Point="100,100" />

<LineSegment Point="0,100" />

</PathSegmentCollection>

</PathFigure>

</PathGeometry>

</Path.Data>

</Path>

WPF中二维图形的坐标系将原点定位在呈现区域（通常是屏幕）的左上角。 在二维系统中，x 轴上的正值朝右，y 轴上的正值朝下。

在三维坐标系中，原点位于呈现区域的中心，x 轴上的正值朝右， y 轴上的正值朝上，z 轴上的正值从原点向外朝向观察者。

如下；

在3D的世界里所有的东西都是用一些列的“三角形”来描述的。因为；

三角形是用来描述一个平面的最细微的几何体，渲染引擎能够依据每个三角形的材质以及场景中的灯光角度来计算它的颜色。

其实就是三点确定一个平面，在一个平面上做计算最简单，考虑的因素最少。如果用三维空间中大于三个点来做渲染基本单位，那么如果这些点不在同一个平面上的话，渲染计算是相当复杂的。

下面来画一个最基本三角形；

<MeshGeometry3D Positions="1,0,0 0,-1,0 0,0,1"/> ，定义了三角形的三个顶点；

<PerspectiveCamera Position="-2,2,2" LookDirection="2,-2,-2" UpDirection="0,1,0"/>

    定义了摄像机的位置和看的方向等；如果改变摄像机的位置，则如下；

先把坐标系整清楚；以及 <MeshGeometry3D Positions="1,0,0 0,-1,0 0,0,1"/> 是定义三个顶点的坐标，下回再整摄像机的位置等；

<Page
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Grid>  
  
  <Viewport3D>
        <Viewport3D.Camera>
            <PerspectiveCamera Position="-2,2,2" LookDirection="2,-2,-2" UpDirection="0,1,0"/>
        </Viewport3D.Camera>
        <Viewport3D.Children>                                          
            <ModelVisual3D x:Name="Light">
                <ModelVisual3D.Content>
                    <AmbientLight/>
                </ModelVisual3D.Content>
            </ModelVisual3D>

        <ModelVisual3D> 
          <ModelVisual3D.Content> 
            <GeometryModel3D> 
                <GeometryModel3D.Geometry>
                  <MeshGeometry3D Positions="-1,0,0 0,-1,0 0,0,-1"/> 
                </GeometryModel3D.Geometry> 
                <GeometryModel3D.Material> 
                  <DiffuseMaterial Brush="Yellow" /> 
                </GeometryModel3D.Material> 
              </GeometryModel3D>
            </ModelVisual3D.Content>
        </ModelVisual3D>
       </Viewport3D.Children> 
</Viewport3D>

  </Grid>
</Page>

修改后三角形自动放大

    <Grid x:Name="LayoutRoot">

        <Grid.RowDefinitions>
            <RowDefinition/>
        </Grid.RowDefinitions>

        

        <Button Width="305" HorizontalAlignment="Left" Content="Button1" Template="{DynamicResource ButtonControlTemplate1}" Cursor="Hand" Margin="52,45,0,142" Click="Button_Click_1">
            <Button.Resources>
                <ControlTemplate x:Key="ButtonControlTemplate1" TargetType="{x:Type Button}">
                    <Grid>
                        <Ellipse x:Name="ButtonEllipse" Width="Auto" Height="Auto" StrokeThickness="4" Fill="White" Stroke="Gray"></Ellipse>
                        <Polygon x:Name="ButtonPolygon" Stretch="Fill" Points="0,50 100,0 100,100" Stroke="White" StrokeThickness="2">
                            <Polygon.Fill>
                                <SolidColorBrush Color="Gray" Opacity="0.4"/>
                            </Polygon.Fill>
                        </Polygon>
                    </Grid>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsMouseOver" Value="True">
                            <Setter TargetName="ButtonPolygon" Property="Fill" Value="Black"></Setter>
                        </Trigger>
                        <Trigger Property="IsPressed" Value="True">
                            <Setter TargetName="ButtonPolygon" Property="Fill" Value="Gray"/>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Button.Resources>
        </Button>
    </Grid>

自定义控件上使用代创建

xaml:

<UserControl x:Class="WpfApplication1.UserControl1"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             mc:Ignorable="d"
             d:DesignHeight="439" d:DesignWidth="437" Loaded="UserControl_Loaded">
    
    <UserControl.Resources>
        <ControlTemplate x:Key="ButtonControlTemplate1" TargetType="{x:Type Button}">
            <Grid>
                <Polygon x:Name="ButtonPolygon" Stretch="Fill" Points="0,50 100,0 100,100" Stroke="White" StrokeThickness="2">
                    <Polygon.Fill>
                        <SolidColorBrush Color="Gray" Opacity="0.4"/>
                    </Polygon.Fill>
                </Polygon>
            </Grid>
            <ControlTemplate.Triggers>
                <Trigger Property="IsMouseOver" Value="True">
                    <Setter TargetName="ButtonPolygon" Property="Fill" Value="Black"></Setter>
                </Trigger>
                <Trigger Property="IsPressed" Value="True">
                    <Setter TargetName="ButtonPolygon" Property="Fill" Value="red"/>
                </Trigger>
            </ControlTemplate.Triggers>
        </ControlTemplate>
    </UserControl.Resources>
    
    
</UserControl>

code:

    public partial class UserControl1 : UserControl
    {
        public UserControl1()
        {
            InitializeComponent();
        }

        private void UserControl_Loaded(object sender, RoutedEventArgs e)
        {
            Button button1 = new Button();
            this.AddChild(button1);
            button1.Template = (ControlTemplate)(this.Resources["ButtonControlTemplate1"]);
            button1.Click += button1_Click;
        }

        private void button1_Click(object sender, RoutedEventArgs e)
        {
            MessageBox.Show("sss");
        }


    }