Canvas: Content layout

Main.xaml

<Grid
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Grid HorizontalAlignment="Center" VerticalAlignment="Center" Background="LightGray" TextElement.Foreground="Black">
    <Grid.Resources>
      <LinearGradientBrush x:Key="BgBrush" StartPoint="0,0" EndPoint="1,1">
        <GradientStop Offset="0" Color="#FF9BDEFF"/>
        <GradientStop Offset="1" Color="#FF69B5FF"/>
      </LinearGradientBrush>
      <Style x:Key="BorderStyle" TargetType="Border">
        <Setter Property="BorderBrush" Value="Black"/>
        <Setter Property="BorderThickness" Value="1"/>
        <Setter Property="Background" Value="{StaticResource BgBrush}"/>
        <Setter Property="Height" Value="50"/>
      </Style>
    </Grid.Resources>
    <Grid.RowDefinitions>
      <RowDefinition Height="Auto"/>
      <RowDefinition/>
    </Grid.RowDefinitions>
    <TextBlock Margin="0,8,0,0" HorizontalAlignment="Center">
      <Run Text="{Binding ActualWidth, ElementName=Canvas, StringFormat=Canvas size: {0}, Mode=OneWay}"/>
      <Run Text="{Binding ActualHeight, ElementName=Canvas, StringFormat=x{0}, Mode=OneWay}"/>
    </TextBlock>
    <Canvas x:Name="Canvas" Width="350" Height="300" Grid.Row="1" Background="White" Margin="8">
      <Border Canvas.Left="20" Canvas.Top="15" Style="{StaticResource BorderStyle}" CornerRadius="0,4,4,4">
        <Grid>
          <TextBlock VerticalAlignment="Top" Margin="2,0,10,0">
            <Run Text="{Binding (Canvas.Left), RelativeSource={RelativeSource AncestorType={x:Type Border}}, StringFormat='(left={0},', Mode=OneWay}"/>
            <Run Text="{Binding (Canvas.Top), RelativeSource={RelativeSource AncestorType={x:Type Border}}, StringFormat='top={0})', Mode=OneWay}"/>
          </TextBlock>
          <Ellipse Fill="Black" Stroke="#00000000" Width="4" Height="4" HorizontalAlignment="Left" VerticalAlignment="Top" StrokeThickness="0" Margin="-2,-2,0,0"/>
        </Grid>
      </Border>
      <Border Canvas.Right="15" Canvas.Top="35" Style="{StaticResource BorderStyle}" CornerRadius="4,0,4,4">
        <Grid>
          <TextBlock VerticalAlignment="Top" Margin="10,0,2,0">
            <Run Text="{Binding (Canvas.Right), RelativeSource={RelativeSource AncestorType={x:Type Border}}, StringFormat='(right={0},', Mode=OneWay}"/>
            <Run Text="{Binding (Canvas.Top), RelativeSource={RelativeSource AncestorType={x:Type Border}}, StringFormat='top={0})', Mode=OneWay}"/>
          </TextBlock>
          <Ellipse Fill="Black" Stroke="#00000000" Width="4" Height="4" HorizontalAlignment="Right" VerticalAlignment="Top" StrokeThickness="0" Margin="0,-2,-2,0"/>
        </Grid>
      </Border>
      <Border Canvas.Left="10" Canvas.Bottom="35" Style="{StaticResource BorderStyle}" CornerRadius="4,4,4,0">
        <Grid>
          <TextBlock VerticalAlignment="Bottom" Margin="2,0,10,0">
            <Run Text="{Binding (Canvas.Left), RelativeSource={RelativeSource AncestorType={x:Type Border}}, StringFormat='(left={0},', Mode=OneWay}"/>
            <Run Text="{Binding (Canvas.Bottom), RelativeSource={RelativeSource AncestorType={x:Type Border}}, StringFormat='bottom={0})', Mode=OneWay}"/>
          </TextBlock>
          <Ellipse Fill="Black" Stroke="#00000000" Width="4" Height="4" HorizontalAlignment="Left" VerticalAlignment="Bottom" StrokeThickness="0" Margin="-2,0,0,-2"/>
        </Grid>
      </Border>
      <Border Canvas.Right="10" Canvas.Bottom="5" Style="{StaticResource BorderStyle}" CornerRadius="4,4,0,4">
        <Grid>
          <TextBlock VerticalAlignment="Bottom" Margin="10,0,2,0">
            <Run Text="{Binding (Canvas.Right), RelativeSource={RelativeSource AncestorType={x:Type Border}}, StringFormat='(right={0},', Mode=OneWay}"/>
            <Run Text="{Binding (Canvas.Bottom), RelativeSource={RelativeSource AncestorType={x:Type Border}}, StringFormat='bottom={0})', Mode=OneWay}"/>
          </TextBlock>
          <Ellipse Fill="Black" Stroke="#00000000" Width="4" Height="4" HorizontalAlignment="Right" VerticalAlignment="Bottom" StrokeThickness="0" Margin="0,0,-2,-2"/>
        </Grid>
      </Border>
      <Border Canvas.Left="160" Canvas.Top="115" Style="{StaticResource BorderStyle}" CornerRadius="0,4,4,4">
        <Grid>
          <TextBlock VerticalAlignment="Top" Margin="2,0,10,0">
            <Run Text="{Binding (Canvas.Left), RelativeSource={RelativeSource AncestorType={x:Type Border}}, StringFormat='(left={0},', Mode=OneWay}"/>
            <Run Text="{Binding (Canvas.Top), RelativeSource={RelativeSource AncestorType={x:Type Border}}, StringFormat='top={0})', Mode=OneWay}"/>
          </TextBlock>
          <Ellipse Fill="Black" Stroke="#00000000" Width="4" Height="4" HorizontalAlignment="Left" VerticalAlignment="Top" StrokeThickness="0" Margin="-2,-2,0,0"/>
        </Grid>
      </Border>
    </Canvas>
  </Grid>
</Grid>