Avalonia/samples/ControlCatalog/Pages/CustomDrawing.xaml

<UserControl xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             xmlns:local="using:ControlCatalog.Pages"
             xmlns:converters="using:ControlCatalog.Converter"
             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
             x:Class="ControlCatalog.Pages.CustomDrawing">

  <UserControl.Resources>
    <converters:DegToRadConverter x:Key="DegToRadConverter"/>
  </UserControl.Resources>
  
  <Grid>
    <Grid.ColumnDefinitions>
      <ColumnDefinition/>
      <ColumnDefinition/>
      <ColumnDefinition/>
    </Grid.ColumnDefinitions>
    <Grid.RowDefinitions>
      <RowDefinition Height="Auto"/>
      <RowDefinition/>
    </Grid.RowDefinitions>

    <StackPanel Orientation="Vertical">
      <TextBlock Text="Translation" HorizontalAlignment="Center"/>
      <Grid ColumnDefinitions="*,*"
            RowDefinitions="Auto,Auto"
            >
        <TextBlock Text="Horizontal"/>
        <TextBlock Text="Vertical" Grid.Column="1"/>
        <TextBox IsEnabled="False" 
                 Text="{Binding ElementName=CustomDrawingControl,
                  Path=ViewportCenterX,
                  Mode=OneWay,
                  StringFormat=\{0:g4\}}"
                 Grid.Row="1"
                 />
        <TextBox IsEnabled="False"
                 Text="{Binding ElementName=CustomDrawingControl,
                  Path=ViewportCenterY, 
                  Mode=OneWay,
                  StringFormat=\{0:g4\}}"
                 Grid.Row="1" Grid.Column="1"
                 />
      </Grid>
    </StackPanel>

    <StackPanel Orientation="Vertical" Grid.Column="1"
                >
      <TextBlock Text="Rotation" HorizontalAlignment="Center"/>
      <StackPanel Orientation="Horizontal" HorizontalAlignment="Center"
                  >
        <Button Content="➖" Width="40" Height="40"
                VerticalContentAlignment="Center"
                VerticalAlignment="Center"
                Click="RotateMinus"
                />
        <TextBox IsEnabled="False"
                 Text="{Binding ElementName=CustomDrawingControl,
                  Path=Rotation, 
                  Converter={StaticResource DegToRadConverter},
                  Mode=OneWay,
                  StringFormat=\{0:g4\}}"
                 Grid.Row="1" Grid.Column="1"
                 />
        <Button Content="➕" Width="40" Height="40"
                VerticalContentAlignment="Center"
                VerticalAlignment="Center"
                Click="RotatePlus"
                />
      </StackPanel>
    </StackPanel>

    <StackPanel Orientation="Vertical" Grid.Column="2"
                >
      <TextBlock Text="Scale" HorizontalAlignment="Center"/>
      <StackPanel Orientation="Horizontal" HorizontalAlignment="Center"
                  >
        <Button Content="➖" Width="40" Height="40"
                VerticalContentAlignment="Center"
                VerticalAlignment="Center"
                Click="ZoomOut"
                />
        <TextBox IsEnabled="False"
                 Text="{Binding ElementName=CustomDrawingControl,
                  Path=Scale, 
                  Mode=OneWay,
                  StringFormat=\{0:g4\}}"
                 Grid.Row="1" Grid.Column="1"
                 />
        <Button Content="➕" Width="40" Height="40"
                VerticalContentAlignment="Center"
                VerticalAlignment="Center"
                Click="ZoomIn"
                />
      </StackPanel>
    </StackPanel>
    
    <Grid Grid.Row="1" Grid.ColumnSpan="3" ClipToBounds="True">
      <local:CustomDrawingExampleControl
        x:Name="CustomDrawingControl"
        />
    </Grid>
  </Grid>
  
</UserControl>