WaymarkPreview.xaml

<UserControl
  x:Class="WaymarkLibrarian.WaymarkPreview"
  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"
  xmlns:local="clr-namespace:WaymarkLibrarian"
  mc:Ignorable="d"
  d:DesignHeight="200" d:DesignWidth="200"
  DataContext="{Binding RelativeSource={RelativeSource Self}, Mode=OneWay}">

  <UserControl.Resources>
    <BooleanToVisibilityConverter x:Key="VisibilityConverter" />
  </UserControl.Resources>

  <Viewbox
    StretchDirection="Both"
    Stretch="UniformToFill">
    <Grid Width="40" Height="40" Background="#111">
      <Canvas
        Width="200" Height="200"
        HorizontalAlignment="Center"
        VerticalAlignment="Center">
        <Line
          X1="100" Y1="0"
          X2="100" Y2="200"
          Stroke="DimGray"
          StrokeThickness="0.2" />

        <Line
          X1="0" Y1="100"
          X2="200" Y2="100"
          Stroke="DimGray"
          StrokeThickness="0.2" />

        <Path Stroke="Silver" StrokeThickness="0.2" Fill="Red" Visibility="{Binding A.IsVisible, Mode=OneWay, Converter={StaticResource VisibilityConverter}}">
          <Path.Data>
            <EllipseGeometry RadiusX="0.7" RadiusY="0.7" Center="{Binding A.Point, Mode=OneWay}" />
          </Path.Data>
        </Path>

        <Path Stroke="Silver" StrokeThickness="0.2" Fill="Yellow" Visibility="{Binding B.IsVisible, Mode=OneWay, Converter={StaticResource VisibilityConverter}}">
          <Path.Data>
            <EllipseGeometry RadiusX="0.7" RadiusY="0.7" Center="{Binding B.Point, Mode=OneWay}" />
          </Path.Data>
        </Path>

        <Path Stroke="Silver" StrokeThickness="0.2" Fill="DodgerBlue" Visibility="{Binding C.IsVisible, Mode=OneWay, Converter={StaticResource VisibilityConverter}}">
          <Path.Data>
            <EllipseGeometry RadiusX="0.7" RadiusY="0.7" Center="{Binding C.Point, Mode=OneWay}" />
          </Path.Data>
        </Path>

        <Path Stroke="Silver" StrokeThickness="0.2" Fill="BlueViolet" Visibility="{Binding D.IsVisible, Mode=OneWay, Converter={StaticResource VisibilityConverter}}">
          <Path.Data>
            <EllipseGeometry RadiusX="0.7" RadiusY="0.7" Center="{Binding D.Point, Mode=OneWay}" />
          </Path.Data>
        </Path>

        <Path Stroke="Red" StrokeThickness="0.3" Fill="Transparent" Visibility="{Binding One.IsVisible, Mode=OneWay, Converter={StaticResource VisibilityConverter}}">
          <Path.Data>
            <EllipseGeometry RadiusX="0.7" RadiusY="0.7" Center="{Binding One.Point, Mode=OneWay}" />
          </Path.Data>
        </Path>

        <Path Stroke="Yellow" StrokeThickness="0.3" Fill="Transparent" Visibility="{Binding Two.IsVisible, Mode=OneWay, Converter={StaticResource VisibilityConverter}}">
          <Path.Data>
            <EllipseGeometry RadiusX="0.7" RadiusY="0.7" Center="{Binding Two.Point, Mode=OneWay}" />
          </Path.Data>
        </Path>

        <Path Stroke="DodgerBlue" StrokeThickness="0.3" Fill="Transparent" Visibility="{Binding Three.IsVisible, Mode=OneWay, Converter={StaticResource VisibilityConverter}}">
          <Path.Data>
            <EllipseGeometry RadiusX="0.7" RadiusY="0.7" Center="{Binding Three.Point, Mode=OneWay}" />
          </Path.Data>
        </Path>

        <Path Stroke="BlueViolet" StrokeThickness="0.3" Fill="Transparent" Visibility="{Binding Four.IsVisible, Mode=OneWay, Converter={StaticResource VisibilityConverter}}">
          <Path.Data>
            <EllipseGeometry RadiusX="0.7" RadiusY="0.7" Center="{Binding Four.Point, Mode=OneWay}" />
          </Path.Data>
        </Path>
      </Canvas>
    </Grid>
  </Viewbox>
</UserControl>