aistudio-wpf-diagram/AIStudio.Wpf.DiagramDesigner/UserControls/LineControl.xaml

<UserControl x:Class="AIStudio.Wpf.DiagramDesigner.LineControl"
             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:s="clr-namespace:AIStudio.Wpf.DiagramDesigner"         
             mc:Ignorable="d" 
             d:DesignHeight="450" d:DesignWidth="800">
    <UserControl.Resources>
        <s:ColorBrushConverter x:Key="ColorBrushConverter" />
        <s:LineDashConverter x:Key="LineDashConverter"/>
        <s:ArrowPathConverter x:Key="ArrowPathConverter"/>
        <s:ArrowSizeConverter x:Key="ArrowSizeConverter"/>
        <s:MathConverter x:Key="MathAddConverter" Operation="Add" />
        <Style x:Key="LineStyle" TargetType="Path">
            <Setter Property="Stroke" Value="{Binding ColorViewModel.LineColor,Converter={StaticResource ColorBrushConverter}}"/>
            <Style.Triggers>
                <DataTrigger Value="True" Binding="{Binding IsSelected}">
                    <Setter Property="Stroke" Value="Black"/>
                </DataTrigger>
            </Style.Triggers>
        </Style>
        <Style x:Key="ArrowStyle" TargetType="Path">
            <!--<Setter Property="Stroke" Value="{Binding ColorViewModel.LineColor,Converter={StaticResource ColorBrushConverter}}"/>-->
            <Setter Property="Fill" Value="{Binding ColorViewModel.LineColor,Converter={StaticResource ColorBrushConverter}}"/>
            <Style.Triggers>
                <DataTrigger Value="True" Binding="{Binding IsSelected}">
                    <!--<Setter Property="Stroke" Value="Black"/>-->
                    <Setter Property="Fill" Value="Black"/>
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </UserControl.Resources>
    <Grid>
        <Canvas x:Name="rootCanvas">
            <Path x:Name="line" StrokeThickness="{Binding ColorViewModel.LineWidth}"  
                                StrokeDashArray="{Binding ColorViewModel.LineDashStyle,Converter={StaticResource LineDashConverter}}"
                                Style="{StaticResource LineStyle}">
                <Path.Data>
                    <MultiBinding Converter="{x:Static s:ConnectionPathConverter.Instance}">
                        <Binding Path="PathGeneratorResult"/>
                    </MultiBinding>
                </Path.Data>
            </Path>

            <Path x:Name="rightarrow" 
                Data="{Binding ShapeViewModel.SinkMarker.Path}"              
                Width="{Binding ShapeViewModel.SinkMarker.Width}"
                Stretch="UniformToFill"   
                HorizontalAlignment="Left"
                VerticalAlignment="Top"    
                RenderTransformOrigin="0.5,0.5"
                Visibility="{Binding Path=IsFullConnection, Converter={x:Static s:BoolToVisibilityConverter.Instance}}"
                Style="{StaticResource ArrowStyle}">
                <Path.RenderTransform>
                    <TransformGroup>
                        <RotateTransform x:Name="rightrot" Angle="{Binding EndAngle}"/>
                        <TranslateTransform X="{Binding EndPoint.X}" Y="{Binding EndPoint.Y}"/>
                    </TransformGroup>
                </Path.RenderTransform>
            </Path>

            <Path x:Name="leftarrow" 
                Data="{Binding ShapeViewModel.SourceMarker.Path}"               
                Width="{Binding ShapeViewModel.SourceMarker.Width}"
                Canvas.Left="{Binding StartPoint.X}"
                Canvas.Top="{Binding StartPoint.Y}"
                Stretch="UniformToFill"
                HorizontalAlignment="Left"
                VerticalAlignment="Top"                                                    
                RenderTransformOrigin="0.5,0.5"
                Visibility="{Binding Path=IsFullConnection, Converter={x:Static s:BoolToVisibilityConverter.Instance}}"
                Style="{StaticResource ArrowStyle}">
                <Path.RenderTransform>
                    <TransformGroup>
                        <RotateTransform x:Name="leftrot" Angle="{Binding StartAngle}"/>
                        <TranslateTransform X="{Binding StartPoint.X}" Y="{Binding StartPoint.Y}"/>
                    </TransformGroup>
                </Path.RenderTransform>
            </Path>

            <Ellipse  x:Name="ball" Fill="{Binding ColorViewModel.FillColor,Converter={StaticResource ColorBrushConverter}}"
                      Width="{Binding ColorViewModel.LineWidth,Converter={StaticResource MathAddConverter},ConverterParameter=4}"
                      Height="{Binding ColorViewModel.LineWidth,Converter={StaticResource MathAddConverter},ConverterParameter=4}"
                      Panel.ZIndex="1" />
        </Canvas>
    </Grid>
</UserControl>