c# - Rendering sharp lines in WPF

Question

If I render the following:

<Grid>
  <Canvas SnapsToDevicePixels="True">  
    <Path Fill="#FF000000" SnapsToDevicePixels="True" Data="M 0.00,0.00 L 2.50,0.00 0.00,10.00 " />
    <Path Fill="#FF260014" SnapsToDevicePixels="True" Data="M 2.50,0.00 L 7.50,0.00 2.50,10.00 0.00,10.00 " />
    <Canvas.RenderTransform>
      <ScaleTransform ScaleX="{Binding ElementName=slider,Path=Value}" ScaleY="{Binding ElementName=slider,Path=Value}" />
    </Canvas.RenderTransform>
  </Canvas>
  <Slider x:Name="slider" Minimum="0" Maximum="50" Value="30"/>
</Grid>

I get this result (Kaxaml):

Notice the thin white line between the two shapes. I searched around and found out this has to do with pixel alignment. I would expect that settings SnapsToDevicePixels="True" would be enough to get rid of the line, but this doesn't work!

Any ideas how to get rid of the white line?

Answer 1

Try turning edge aliasing on with RenderOptions, like this (see Grid properties)

<Grid RenderOptions.EdgeMode="Aliased">
  <Canvas SnapsToDevicePixels="True">  
        <Path Fill="#FF000000" SnapsToDevicePixels="True" Data="M 0.00,0.00 L 2.50,0.00 0.00,10.00 " />
        <Path Fill="#FF260014" SnapsToDevicePixels="True" Data="M 2.50,0.00 L 7.50,0.00 2.50,10.00 0.00,10.00 " />
        <Canvas.RenderTransform>
          <ScaleTransform ScaleX="{Binding ElementName=slider,Path=Value}" ScaleY="{Binding ElementName=slider,Path=Value}" />
        </Canvas.RenderTransform>
  </Canvas>

  <Slider x:Name="slider" Minimum="0" Maximum="50" Value="30"/>
</Grid>