Combine Shapes in Windows Presentation Foundation
Sometimes it's necessary to combine two shapes to get a new custom shape. Windows Presentation Foundation and XAML provide all means to do this easily.
Using <CombinedGeometry /> element you can combine two shapes in a path. It can combine two shapes via its child elements (<CombinedGeometry.Geometry1 /> and <CombinedGeometry.Geometry2). Each of these elements can get a geometry and their parent, <CombinedGeometry />, can combine them.
<CombinedGeometry /> has a GeometryCombineMode attribute to set the combine mode. It can get one of following values. To understand these modes apply these operations to two sets in mathematics!
- Union: New shape contains all points of two older shapes. This is the default value.
- Intersect: New shape contains all points that are shared between two shapes.
- Xor: New shape contains all points between two older shapes except what is shared between them.
- Exclude: New shape contains all points between first shape and not second shape.
Let's see some example.
Below is a XAML code that draws two ellipses and fills them with LightSkyBlue color and Black border. It uses Union mode to combine two shapes.
<Window x:Class="CombineShapes.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Combine Shapes in WPF" Height="330" Width="310"
>
<StackPanel>
<Path Fill="LightSkyBlue" Stroke="Black">
<Path.Data>
<CombinedGeometry GeometryCombineMode="Union">
<CombinedGeometry.Geometry1>
<EllipseGeometry Center="100,150" RadiusX="70" RadiusY="30" />
</CombinedGeometry.Geometry1>
<CombinedGeometry.Geometry2>
<EllipseGeometry Center="200,150" RadiusX="70" RadiusY="30" />
</CombinedGeometry.Geometry2>
</CombinedGeometry>
</Path.Data>
</Path>
</StackPanel>
</Window>
In second example Intersect combine mode is used.
<Window x:Class="CombineShapes.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Combine Shapes in WPF" Height="330" Width="310"
>
<StackPanel>
<Path Fill="LightSkyBlue" Stroke="Black">
<Path.Data>
<CombinedGeometry GeometryCombineMode="Intersect">
<CombinedGeometry.Geometry1>
<EllipseGeometry Center="100,150" RadiusX="70" RadiusY="30" />
</CombinedGeometry.Geometry1>
<CombinedGeometry.Geometry2>
<EllipseGeometry Center="200,150" RadiusX="70" RadiusY="30" />
</CombinedGeometry.Geometry2>
</CombinedGeometry>
</Path.Data>
</Path>
</StackPanel>
</Window>
Third code uses Xor mode to combine shapes.
<Window x:Class="CombineShapes.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Combine Shapes in WPF" Height="330" Width="310"
>
<StackPanel>
<Path Fill="LightSkyBlue" Stroke="Black">
<Path.Data>
<CombinedGeometry GeometryCombineMode="Xor">
<CombinedGeometry.Geometry1>
<EllipseGeometry Center="100,150" RadiusX="70" RadiusY="30" />
</CombinedGeometry.Geometry1>
<CombinedGeometry.Geometry2>
<EllipseGeometry Center="200,150" RadiusX="70" RadiusY="30" />
</CombinedGeometry.Geometry2>
</CombinedGeometry>
</Path.Data>
</Path>
</StackPanel>
</Window>
And finally last code and Exclude mode.
<Window x:Class="CombineShapes.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Combine Shapes in WPF" Height="330" Width="310"
>
<StackPanel>
<Path Fill="LightSkyBlue" Stroke="Black">
<Path.Data>
<CombinedGeometry GeometryCombineMode="Exclude">
<CombinedGeometry.Geometry1>
<EllipseGeometry Center="100,150" RadiusX="70" RadiusY="30" />
</CombinedGeometry.Geometry1>
<CombinedGeometry.Geometry2>
<EllipseGeometry Center="200,150" RadiusX="70" RadiusY="30" />
</CombinedGeometry.Geometry2>
</CombinedGeometry>
</Path.Data>
</Path>
</StackPanel>
</Window>
It's also possible to combine more than two shapes using a mathematical tip: when something is true for K it's possible to extend it for K+1 using mathematical induction!
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2 Comments : 12.21.06
#1
DotNetKicks.com
12.21.2006 @ 1:00 PM