sourcegit/src/Views/TextDiffView.axaml

<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:m="using:SourceGit.Models"
             xmlns:vm="using:SourceGit.ViewModels"
             xmlns:v="using:SourceGit.Views"
             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
             x:Class="SourceGit.Views.TextDiffView"
             x:Name="ThisControl"
             Background="{DynamicResource Brush.Contents}">
  <Grid>
    <ContentControl x:Name="Editor">
      <ContentControl.DataTemplates>
        <DataTemplate DataType="m:TextDiff">
          <v:CombinedTextDiffPresenter FileName="{Binding File}"
                                       Foreground="{DynamicResource Brush.FG1}"
                                       LineBrush="{DynamicResource Brush.Border2}"
                                       EmptyContentBackground="{DynamicResource Brush.Diff.EmptyBG}"
                                       AddedContentBackground="{DynamicResource Brush.Diff.AddedBG}"
                                       DeletedContentBackground="{DynamicResource Brush.Diff.DeletedBG}"
                                       AddedHighlightBrush="{DynamicResource Brush.Diff.AddedHighlight}"
                                       DeletedHighlightBrush="{DynamicResource Brush.Diff.DeletedHighlight}"
                                       IndicatorForeground="{DynamicResource Brush.FG2}"
                                       FontFamily="{Binding Source={x:Static vm:Preference.Instance}, Path=MonospaceFont}"
                                       UseSyntaxHighlighting="{Binding Source={x:Static vm:Preference.Instance}, Path=UseSyntaxHighlighting}"
                                       WordWrap="{Binding Source={x:Static vm:Preference.Instance}, Path=EnableDiffViewWordWrap}"
                                       ShowHiddenSymbols="{Binding Source={x:Static vm:Preference.Instance}, Path=ShowHiddenSymbolsInDiffView}"
                                       EnableChunkSelection="{Binding #ThisControl.EnableChunkSelection}"
                                       SelectedChunk="{Binding #ThisControl.SelectedChunk, Mode=TwoWay}"/>
        </DataTemplate>

        <DataTemplate DataType="vm:TwoSideTextDiff">
          <Grid ColumnDefinitions="*,1,*">
            <v:SingleSideTextDiffPresenter Grid.Column="0"
                                           IsOld="True"
                                           FileName="{Binding File}"
                                           Foreground="{DynamicResource Brush.FG1}"
                                           LineBrush="{DynamicResource Brush.Border2}"
                                           EmptyContentBackground="{DynamicResource Brush.Diff.EmptyBG}"
                                           AddedContentBackground="{DynamicResource Brush.Diff.AddedBG}"
                                           DeletedContentBackground="{DynamicResource Brush.Diff.DeletedBG}"
                                           AddedHighlightBrush="{DynamicResource Brush.Diff.AddedHighlight}"
                                           DeletedHighlightBrush="{DynamicResource Brush.Diff.DeletedHighlight}"
                                           IndicatorForeground="{DynamicResource Brush.FG2}"
                                           FontFamily="{Binding Source={x:Static vm:Preference.Instance}, Path=MonospaceFont}"
                                           UseSyntaxHighlighting="{Binding Source={x:Static vm:Preference.Instance}, Path=UseSyntaxHighlighting}"
                                           WordWrap="{Binding Source={x:Static vm:Preference.Instance}, Path=EnableDiffViewWordWrap}"
                                           ShowHiddenSymbols="{Binding Source={x:Static vm:Preference.Instance}, Path=ShowHiddenSymbolsInDiffView}"
                                           EnableChunkSelection="{Binding #ThisControl.EnableChunkSelection}"
                                           SelectedChunk="{Binding #ThisControl.SelectedChunk, Mode=TwoWay}"/>

            <Rectangle Grid.Column="1" Fill="{DynamicResource Brush.Border2}" Width="1" HorizontalAlignment="Center" VerticalAlignment="Stretch"/>

            <v:SingleSideTextDiffPresenter Grid.Column="2"
                                           IsOld="False"
                                           FileName="{Binding File}"
                                           Foreground="{DynamicResource Brush.FG1}"
                                           LineBrush="{DynamicResource Brush.Border2}"
                                           EmptyContentBackground="{DynamicResource Brush.Diff.EmptyBG}"
                                           AddedContentBackground="{DynamicResource Brush.Diff.AddedBG}"
                                           DeletedContentBackground="{DynamicResource Brush.Diff.DeletedBG}"
                                           AddedHighlightBrush="{DynamicResource Brush.Diff.AddedHighlight}"
                                           DeletedHighlightBrush="{DynamicResource Brush.Diff.DeletedHighlight}"
                                           IndicatorForeground="{DynamicResource Brush.FG2}"
                                           FontFamily="{Binding Source={x:Static vm:Preference.Instance}, Path=MonospaceFont}"
                                           UseSyntaxHighlighting="{Binding Source={x:Static vm:Preference.Instance}, Path=UseSyntaxHighlighting}"
                                           WordWrap="{Binding Source={x:Static vm:Preference.Instance}, Path=EnableDiffViewWordWrap}"
                                           ShowHiddenSymbols="{Binding Source={x:Static vm:Preference.Instance}, Path=ShowHiddenSymbolsInDiffView}"
                                           EnableChunkSelection="{Binding #ThisControl.EnableChunkSelection}"
                                           SelectedChunk="{Binding #ThisControl.SelectedChunk, Mode=TwoWay}"/>
          </Grid>
        </DataTemplate>
      </ContentControl.DataTemplates>
    </ContentControl>

    <StackPanel x:Name="Popup" IsVisible="False" Orientation="Horizontal" VerticalAlignment="Top" HorizontalAlignment="Right" Effect="drop-shadow(0 0 6 #40000000)">
      <Button Classes="flat" Content="{DynamicResource Text.Hunk.Stage}" Click="OnStageChunk" IsVisible="{Binding #ThisControl.IsUnstagedChange}"/>
      <Button Classes="flat" Content="{DynamicResource Text.Hunk.Unstage}" Click="OnUnstageChunk" IsVisible="{Binding #ThisControl.IsUnstagedChange, Converter={x:Static BoolConverters.Not}}"/>
      <Button Classes="flat" Content="{DynamicResource Text.Hunk.Discard}" Margin="8,0,0,0" Click="OnDiscardChunk"/>
    </StackPanel>
  </Grid>
</UserControl>