enhance: leave the current state until we got the new diff result to reduce flickering

src/SourceGit/Models/TextMateHelper.cs

@@ -0,0 +1,59 @@
+using System.IO;
+
+using Avalonia.Styling;
+
+using AvaloniaEdit;
+using AvaloniaEdit.TextMate;
+
+using TextMateSharp.Grammars;
+
+namespace SourceGit.Models
+{
+    public static class TextMateHelper
+    {
+        public static TextMate.Installation CreateForEditor(TextEditor editor)
+        {
+            if (App.Current?.ActualThemeVariant == ThemeVariant.Dark)
+            {
+                return editor.InstallTextMate(new RegistryOptions(ThemeName.DarkPlus));
+            }
+            else
+            {
+                return editor.InstallTextMate(new RegistryOptions(ThemeName.LightPlus));
+            }            
+        }
+
+        public static void SetThemeByApp(TextMate.Installation installation)
+        {
+            if (installation == null) return;
+
+            var reg = installation.RegistryOptions as RegistryOptions;
+            if (App.Current?.ActualThemeVariant == ThemeVariant.Dark)
+            {
+                installation.SetTheme(reg.LoadTheme(ThemeName.DarkPlus));
+            }
+            else
+            {
+                installation.SetTheme(reg.LoadTheme(ThemeName.LightPlus));
+            }
+        }
+
+        public static void SetGrammarByFileName(TextMate.Installation installation, string filePath)
+        {
+            if (installation == null) return;
+
+            var ext = Path.GetExtension(filePath);
+            if (ext == ".h")
+            {
+                ext = ".cpp";
+            }
+            else if (ext == ".resx")
+            {
+                ext = ".xml";
+            }
+
+            var reg = installation.RegistryOptions as RegistryOptions;
+            installation.SetGrammar(reg.GetScopeByExtension(ext));
+        }
+    }
+}

src/SourceGit/ViewModels/CommitDetail.cs

@@ -67,7 +67,7 @@ namespace SourceGit.ViewModels
                     else
                     {
                         SelectedChangeNode = FileTreeNode.SelectByPath(_changeTree, value.Path);
-                        DiffContext = new DiffContext(_repo, new Models.DiffOption(_commit, value));
+                        DiffContext = new DiffContext(_repo, new Models.DiffOption(_commit, value), _diffContext);
                     }
                 }
             }

src/SourceGit/ViewModels/DiffContext.cs

@@ -70,10 +70,11 @@ namespace SourceGit.ViewModels
             set => SetProperty(ref _syncScrollOffset, value);
         }
 
-        public DiffContext(string repo, Models.DiffOption option)
+        public DiffContext(string repo, Models.DiffOption option, DiffContext previous = null)
         {
             _repo = repo;
             _option = option;
+            _content = previous != null ? previous._content : null;
 
             OnPropertyChanged(nameof(FilePath));
             OnPropertyChanged(nameof(IsOrgFilePathVisible));
@@ -101,7 +102,7 @@ namespace SourceGit.ViewModels
                     }
                 }
 
-                Dispatcher.UIThread.InvokeAsync(() =>
+                Dispatcher.UIThread.Post(() =>
                 {
                     if (latest.IsBinary)
                     {

src/SourceGit/ViewModels/FileHistories.cs

@@ -39,7 +39,7 @@ namespace SourceGit.ViewModels
                     }
                     else
                     {
-                        DiffContext = new DiffContext(_repo, new Models.DiffOption(value, _file));
+                        DiffContext = new DiffContext(_repo, new Models.DiffOption(value, _file), _diffContext);
                     }
                 }
             }

src/SourceGit/ViewModels/RevisionCompare.cs

@@ -51,7 +51,7 @@ namespace SourceGit.ViewModels
                     else
                     {
                         SelectedNode = FileTreeNode.SelectByPath(_changeTree, value.Path);
-                        DiffContext = new DiffContext(_repo, new Models.DiffOption(StartPoint.SHA, EndPoint.SHA, value));
+                        DiffContext = new DiffContext(_repo, new Models.DiffOption(StartPoint.SHA, EndPoint.SHA, value), _diffContext);
                     }
                 }
             }

src/SourceGit/ViewModels/StashesPage.cs

@@ -77,7 +77,7 @@ namespace SourceGit.ViewModels
                     }
                     else
                     {
-                        DiffContext = new DiffContext(_repo.FullPath, new Models.DiffOption($"{_selectedStash.SHA}^", _selectedStash.SHA, value));
+                        DiffContext = new DiffContext(_repo.FullPath, new Models.DiffOption($"{_selectedStash.SHA}^", _selectedStash.SHA, value), _diffContext);
                     }
                 }
             }

src/SourceGit/ViewModels/WorkingCopy.cs

@@ -287,7 +287,14 @@ namespace SourceGit.ViewModels
             }
             else
             {
-                DetailContext = new DiffContext(_repo.FullPath, new Models.DiffOption(change, isUnstaged));
+                if (_detailContext is DiffContext previous)
+                {
+                    DetailContext = new DiffContext(_repo.FullPath, new Models.DiffOption(change, isUnstaged), previous);
+                }
+                else
+                {
+                    DetailContext = new DiffContext(_repo.FullPath, new Models.DiffOption(change, isUnstaged));
+                }
             }
         }
 

src/SourceGit/Views/Blame.axaml.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Globalization;
-using System.IO;
 
 using Avalonia;
 using Avalonia.Controls;
@@ -9,7 +8,6 @@ using Avalonia.Controls.ApplicationLifetimes;
 using Avalonia.Input;
 using Avalonia.Interactivity;
 using Avalonia.Media;
-using Avalonia.Styling;
 
 using AvaloniaEdit;
 using AvaloniaEdit.Document;
@@ -18,8 +16,6 @@ using AvaloniaEdit.Rendering;
 using AvaloniaEdit.TextMate;
 using AvaloniaEdit.Utils;
 
-using TextMateSharp.Grammars;
-
 namespace SourceGit.Views
 {
     public class BlameTextEditor : TextEditor
@@ -214,6 +210,16 @@ namespace SourceGit.Views
             IsReadOnly = true;
             ShowLineNumbers = false;
             WordWrap = false;
+
+            _textMate = Models.TextMateHelper.CreateForEditor(this);
+
+            TextArea.LeftMargins.Add(new LineNumberMargin() { Margin = new Thickness(8, 0) });
+            TextArea.LeftMargins.Add(new VerticalSeperatorMargin(this));
+            TextArea.LeftMargins.Add(new CommitInfoMargin(this) { Margin = new Thickness(8, 0) });
+            TextArea.LeftMargins.Add(new VerticalSeperatorMargin(this));
+            TextArea.TextView.ContextRequested += OnTextViewContextRequested;
+            TextArea.TextView.VisualLinesChanged += OnTextViewVisualLinesChanged;
+            TextArea.TextView.Margin = new Thickness(4, 0);
         }
 
         public void OnCommitSHAClicked(string sha)
@@ -224,31 +230,6 @@ namespace SourceGit.Views
             }
         }
 
-        protected override void OnLoaded(RoutedEventArgs e)
-        {
-            base.OnLoaded(e);
-
-            TextArea.LeftMargins.Add(new LineNumberMargin() { Margin = new Thickness(8, 0) });
-            TextArea.LeftMargins.Add(new VerticalSeperatorMargin(this));
-            TextArea.LeftMargins.Add(new CommitInfoMargin(this) { Margin = new Thickness(8, 0) });
-            TextArea.LeftMargins.Add(new VerticalSeperatorMargin(this));
-            TextArea.TextView.ContextRequested += OnTextViewContextRequested;
-            TextArea.TextView.VisualLinesChanged += OnTextViewVisualLinesChanged;
-            TextArea.TextView.Margin = new Thickness(4, 0);
-
-            if (App.Current?.ActualThemeVariant == ThemeVariant.Dark)
-            {
-                _registryOptions = new RegistryOptions(ThemeName.DarkPlus);
-            }
-            else
-            {
-                _registryOptions = new RegistryOptions(ThemeName.LightPlus);
-            }
-
-            _textMate = this.InstallTextMate(_registryOptions);
-            UpdateGrammar();
-        }
-
         protected override void OnUnloaded(RoutedEventArgs e)
         {
             base.OnUnloaded(e);
@@ -257,9 +238,11 @@ namespace SourceGit.Views
             TextArea.TextView.ContextRequested -= OnTextViewContextRequested;
             TextArea.TextView.VisualLinesChanged -= OnTextViewVisualLinesChanged;
 
-            _registryOptions = null;
+            if (_textMate != null)
-            _textMate.Dispose();
+            {
-            _textMate = null;
+                _textMate.Dispose();
+                _textMate = null;
+            }
         }
 
         protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs change)
@@ -270,24 +253,17 @@ namespace SourceGit.Views
             {
                 if (BlameData != null)
                 {
+                    Models.TextMateHelper.SetGrammarByFileName(_textMate, BlameData.File);
                     Text = BlameData.Content;
-                    UpdateGrammar();
                 }
                 else
                 {
                     Text = string.Empty;
                 }
             }
-            else if (change.Property.Name == "ActualThemeVariant" && change.NewValue != null && _textMate != null)
+            else if (change.Property.Name == "ActualThemeVariant" && change.NewValue != null)
             {
-                if (App.Current?.ActualThemeVariant == ThemeVariant.Dark)
+                Models.TextMateHelper.SetThemeByApp(_textMate);
-                {
-                    _textMate.SetTheme(_registryOptions.LoadTheme(ThemeName.DarkPlus));
-                }
-                else
-                {
-                    _textMate.SetTheme(_registryOptions.LoadTheme(ThemeName.LightPlus));
-                }
             }
         }
 
@@ -329,22 +305,6 @@ namespace SourceGit.Views
             }
         }
 
-        private void UpdateGrammar()
-        {
-            if (_textMate == null || BlameData == null) return;
-
-            var ext = Path.GetExtension(BlameData.File);
-            if (ext == ".h")
-            {
-                _textMate.SetGrammar(_registryOptions.GetScopeByLanguageId("cpp"));
-            }
-            else
-            {
-                _textMate.SetGrammar(_registryOptions.GetScopeByExtension(ext));
-            }
-        }
-
-        private RegistryOptions _registryOptions = null;
         private TextMate.Installation _textMate = null;
     }
 

src/SourceGit/Views/RevisionFiles.axaml.cs

@@ -1,23 +1,18 @@
 using System;
-using System.IO;
 
 using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Controls.Primitives;
 using Avalonia.Interactivity;
 using Avalonia.Media;
-using Avalonia.Styling;
 
 using AvaloniaEdit;
 using AvaloniaEdit.Document;
 using AvaloniaEdit.Editing;
 using AvaloniaEdit.TextMate;
 
-using TextMateSharp.Grammars;
-
 namespace SourceGit.Views
 {
-
     public class RevisionTextFileView : TextEditor
     {
         protected override Type StyleKeyOverride => typeof(TextEditor);
@@ -39,17 +34,12 @@ namespace SourceGit.Views
             base.OnLoaded(e);
 
             TextArea.TextView.ContextRequested += OnTextViewContextRequested;
-            if (App.Current?.ActualThemeVariant == ThemeVariant.Dark)
-            {
-                _registryOptions = new RegistryOptions(ThemeName.DarkPlus);
-            }
-            else
-            {
-                _registryOptions = new RegistryOptions(ThemeName.LightPlus);
-            }
 
-            _textMate = this.InstallTextMate(_registryOptions);
+            _textMate = Models.TextMateHelper.CreateForEditor(this);
-            UpdateGrammar();
+            if (DataContext is Models.RevisionTextFile source)
+            {
+                Models.TextMateHelper.SetGrammarByFileName(_textMate, source.FileName);
+            }
         }
 
         protected override void OnUnloaded(RoutedEventArgs e)
@@ -57,9 +47,13 @@ namespace SourceGit.Views
             base.OnUnloaded(e);
 
             TextArea.TextView.ContextRequested -= OnTextViewContextRequested;
-            _registryOptions = null;
+
-            _textMate.Dispose();
+            if (_textMate != null)
-            _textMate = null;
+            {
+                _textMate.Dispose();
+                _textMate = null;
+            }
+
             GC.Collect();
         }
 
@@ -70,7 +64,7 @@ namespace SourceGit.Views
             var source = DataContext as Models.RevisionTextFile;
             if (source != null)
             {
-                UpdateGrammar();
+                Models.TextMateHelper.SetGrammarByFileName(_textMate, source.FileName);
                 Text = source.Content;
             }
         }
@@ -79,16 +73,9 @@ namespace SourceGit.Views
         {
             base.OnPropertyChanged(change);
 
-            if (change.Property.Name == "ActualThemeVariant" && change.NewValue != null && _textMate != null)
+            if (change.Property.Name == "ActualThemeVariant" && change.NewValue != null)
             {
-                if (App.Current?.ActualThemeVariant == ThemeVariant.Dark)
+                Models.TextMateHelper.SetThemeByApp(_textMate);
-                {
-                    _textMate.SetTheme(_registryOptions.LoadTheme(ThemeName.DarkPlus));
-                }
-                else
-                {
-                    _textMate.SetTheme(_registryOptions.LoadTheme(ThemeName.LightPlus));
-                }
             }
         }
 
@@ -118,25 +105,6 @@ namespace SourceGit.Views
             e.Handled = true;
         }
 
-        private void UpdateGrammar()
-        {
-            if (_textMate == null) return;
-
-            var src = DataContext as Models.RevisionTextFile;
-            if (src == null) return;
-
-            var ext = Path.GetExtension(src.FileName);
-            if (ext == ".h")
-            {
-                _textMate.SetGrammar(_registryOptions.GetScopeByLanguageId("cpp"));
-            }
-            else
-            {
-                _textMate.SetGrammar(_registryOptions.GetScopeByExtension(ext));
-            }
-        }
-
-        private RegistryOptions _registryOptions = null;
         private TextMate.Installation _textMate = null;
     }
 

src/SourceGit/Views/TextDiffView.axaml.cs

@@ -9,7 +9,6 @@ using Avalonia.Controls;
 using Avalonia.Controls.Primitives;
 using Avalonia.Interactivity;
 using Avalonia.Media;
-using Avalonia.Styling;
 using Avalonia.VisualTree;
 
 using AvaloniaEdit;
@@ -19,8 +18,6 @@ using AvaloniaEdit.Rendering;
 using AvaloniaEdit.TextMate;
 using AvaloniaEdit.Utils;
 
-using TextMateSharp.Grammars;
-
 namespace SourceGit.Views
 {
     public class CombinedTextDiffPresenter : TextEditor
@@ -160,10 +157,9 @@ namespace SourceGit.Views
             private static readonly Brush HL_ADDED = new SolidColorBrush(Color.FromArgb(90, 0, 255, 0));
             private static readonly Brush HL_DELETED = new SolidColorBrush(Color.FromArgb(80, 255, 0, 0));
 
-            public LineStyleTransformer(CombinedTextDiffPresenter editor, IBrush indicatorFG)
+            public LineStyleTransformer(CombinedTextDiffPresenter editor)
             {
                 _editor = editor;
-                _indicatorFG = indicatorFG;
                 _indicatorTypeface = new Typeface("fonts:SourceGit#JetBrains Mono", FontStyle.Italic);
             }
 
@@ -177,7 +173,7 @@ namespace SourceGit.Views
                 {
                     ChangeLinePart(line.Offset, line.EndOffset, v =>
                     {
-                        v.TextRunProperties.SetForegroundBrush(_indicatorFG);
+                        v.TextRunProperties.SetForegroundBrush(_editor.SecondaryFG);
                         v.TextRunProperties.SetTypeface(_indicatorTypeface);
                     });
 
@@ -198,7 +194,6 @@ namespace SourceGit.Views
             }
 
             private readonly CombinedTextDiffPresenter _editor;
-            private readonly IBrush _indicatorFG = Brushes.DarkGray;
             private readonly Typeface _indicatorTypeface = Typeface.Default;
         }
 
@@ -233,14 +228,11 @@ namespace SourceGit.Views
 
         public CombinedTextDiffPresenter() : base(new TextArea(), new TextDocument())
         {
+            _lineStyleTransformer = new LineStyleTransformer(this);
+
             IsReadOnly = true;
             ShowLineNumbers = false;
             WordWrap = false;
-        }
-
-        protected override void OnLoaded(RoutedEventArgs e)
-        {
-            base.OnLoaded(e);
 
             TextArea.LeftMargins.Add(new LineNumberMargin(this, true) { Margin = new Thickness(8, 0) });
             TextArea.LeftMargins.Add(new VerticalSeperatorMargin(this));
@@ -249,37 +241,34 @@ namespace SourceGit.Views
 
             TextArea.TextView.Margin = new Thickness(4, 0);
             TextArea.TextView.BackgroundRenderers.Add(new LineBackgroundRenderer(this));
+        }
+
+        protected override void OnLoaded(RoutedEventArgs e)
+        {
+            base.OnLoaded(e);
+
+            _textMate = Models.TextMateHelper.CreateForEditor(this);
+            if (DiffData != null) Models.TextMateHelper.SetGrammarByFileName(_textMate, DiffData.File);
+
+            TextArea.TextView.LineTransformers.Add(_lineStyleTransformer);
             TextArea.TextView.ContextRequested += OnTextViewContextRequested;
             TextArea.TextView.ScrollOffsetChanged += OnTextViewScrollOffsetChanged;
-
-            if (App.Current?.ActualThemeVariant == ThemeVariant.Dark)
-            {
-                _registryOptions = new RegistryOptions(ThemeName.DarkPlus);
-            }
-            else
-            {
-                _registryOptions = new RegistryOptions(ThemeName.LightPlus);
-            }
-
-            _textMate = this.InstallTextMate(_registryOptions);
-            UpdateGrammar();
-
-            // This line must after InstallTextMate.
-            TextArea.TextView.LineTransformers.Add(new LineStyleTransformer(this, SecondaryFG));
         }
 
         protected override void OnUnloaded(RoutedEventArgs e)
         {
             base.OnUnloaded(e);
 
-            TextArea.LeftMargins.Clear();
+            TextArea.TextView.LineTransformers.Remove(_lineStyleTransformer);
-            TextArea.TextView.BackgroundRenderers.Clear();
-            TextArea.TextView.LineTransformers.Clear();
             TextArea.TextView.ContextRequested -= OnTextViewContextRequested;
             TextArea.TextView.ScrollOffsetChanged -= OnTextViewScrollOffsetChanged;
-            _registryOptions = null;
+
-            _textMate.Dispose();
+            if (_textMate != null)
-            _textMate = null;
+            {
+                _textMate.Dispose();
+                _textMate = null;
+            }
+
             GC.Collect();
         }
 
@@ -328,7 +317,7 @@ namespace SourceGit.Views
                         builder.AppendLine(line.Content);
                     }
 
-                    UpdateGrammar();
+                    Models.TextMateHelper.SetGrammarByFileName(_textMate, DiffData.File);
                     Text = builder.ToString();
                 }
                 else
@@ -344,36 +333,14 @@ namespace SourceGit.Views
                     scrollable.Offset = SyncScrollOffset;
                 }
             }
-            else if (change.Property.Name == "ActualThemeVariant" && change.NewValue != null && _textMate != null)
+            else if (change.Property.Name == "ActualThemeVariant" && change.NewValue != null)
             {
-                if (App.Current?.ActualThemeVariant == ThemeVariant.Dark)
+                Models.TextMateHelper.SetThemeByApp(_textMate);
-                {
-                    _textMate.SetTheme(_registryOptions.LoadTheme(ThemeName.DarkPlus));
-                }
-                else
-                {
-                    _textMate.SetTheme(_registryOptions.LoadTheme(ThemeName.LightPlus));
-                }
             }
         }
 
-        private void UpdateGrammar()
-        {
-            if (_textMate == null || DiffData == null) return;
-
-            var ext = Path.GetExtension(DiffData.File);
-            if (ext == ".h")
-            {
-                _textMate.SetGrammar(_registryOptions.GetScopeByLanguageId("cpp"));
-            }
-            else
-            {
-                _textMate.SetGrammar(_registryOptions.GetScopeByExtension(ext));
-            }
-        }
-
-        private RegistryOptions _registryOptions;
         private TextMate.Installation _textMate;
+        private LineStyleTransformer _lineStyleTransformer = null;
     }
 
     public class SingleSideTextDiffPresenter : TextEditor
@@ -513,10 +480,9 @@ namespace SourceGit.Views
             private static readonly Brush HL_ADDED = new SolidColorBrush(Color.FromArgb(90, 0, 255, 0));
             private static readonly Brush HL_DELETED = new SolidColorBrush(Color.FromArgb(80, 255, 0, 0));
 
-            public LineStyleTransformer(SingleSideTextDiffPresenter editor, IBrush indicatorFG)
+            public LineStyleTransformer(SingleSideTextDiffPresenter editor)
             {
                 _editor = editor;
-                _indicatorFG = indicatorFG;
                 _indicatorTypeface = new Typeface("fonts:SourceGit#JetBrains Mono", FontStyle.Italic);
             }
 
@@ -531,7 +497,7 @@ namespace SourceGit.Views
                 {
                     ChangeLinePart(line.Offset, line.EndOffset, v =>
                     {
-                        v.TextRunProperties.SetForegroundBrush(_indicatorFG);
+                        v.TextRunProperties.SetForegroundBrush(_editor.SecondaryFG);
                         v.TextRunProperties.SetTypeface(_indicatorTypeface);
                     });
 
@@ -552,7 +518,6 @@ namespace SourceGit.Views
             }
 
             private readonly SingleSideTextDiffPresenter _editor;
-            private readonly IBrush _indicatorFG = Brushes.DarkGray;
             private readonly Typeface _indicatorTypeface = Typeface.Default;
         }
 
@@ -596,9 +561,16 @@ namespace SourceGit.Views
 
         public SingleSideTextDiffPresenter() : base(new TextArea(), new TextDocument())
         {
+            _lineStyleTransformer = new LineStyleTransformer(this);
+
             IsReadOnly = true;
             ShowLineNumbers = false;
             WordWrap = false;
+
+            TextArea.LeftMargins.Add(new LineNumberMargin(this) { Margin = new Thickness(8, 0) });
+            TextArea.LeftMargins.Add(new VerticalSeperatorMargin(this));
+            TextArea.TextView.Margin = new Thickness(4, 0);
+            TextArea.TextView.BackgroundRenderers.Add(new LineBackgroundRenderer(this));
         }
 
         protected override void OnLoaded(RoutedEventArgs e)
@@ -612,26 +584,11 @@ namespace SourceGit.Views
                 _scrollViewer.ScrollChanged += OnTextViewScrollChanged;
             }
 
-            TextArea.LeftMargins.Add(new LineNumberMargin(this) { Margin = new Thickness(8, 0) });
+            _textMate = Models.TextMateHelper.CreateForEditor(this);
-            TextArea.LeftMargins.Add(new VerticalSeperatorMargin(this));
+            if (DiffData != null) Models.TextMateHelper.SetGrammarByFileName(_textMate, DiffData.File);
-            TextArea.TextView.Margin = new Thickness(4, 0);
+
-            TextArea.TextView.BackgroundRenderers.Add(new LineBackgroundRenderer(this));
+            TextArea.TextView.LineTransformers.Add(_lineStyleTransformer);
             TextArea.TextView.ContextRequested += OnTextViewContextRequested;
-
-            if (App.Current?.ActualThemeVariant == ThemeVariant.Dark)
-            {
-                _registryOptions = new RegistryOptions(ThemeName.DarkPlus);
-            }
-            else
-            {
-                _registryOptions = new RegistryOptions(ThemeName.LightPlus);
-            }
-
-            _textMate = this.InstallTextMate(_registryOptions);
-            UpdateGrammar();
-
-            // This line must after InstallTextMate
-            TextArea.TextView.LineTransformers.Add(new LineStyleTransformer(this, SecondaryFG));
         }
 
         protected override void OnUnloaded(RoutedEventArgs e)
@@ -644,13 +601,15 @@ namespace SourceGit.Views
                 _scrollViewer = null;
             }
 
-            TextArea.LeftMargins.Clear();
+            if (_textMate != null)
-            TextArea.TextView.BackgroundRenderers.Clear();
+            {
-            TextArea.TextView.LineTransformers.Clear();
+                _textMate.Dispose();
+                _textMate = null;
+            }
+
+            TextArea.TextView.LineTransformers.Remove(_lineStyleTransformer);
             TextArea.TextView.ContextRequested -= OnTextViewContextRequested;
-            _registryOptions = null;
+
-            _textMate.Dispose();
-            _textMate = null;
             GC.Collect();
         }
 
@@ -716,7 +675,7 @@ namespace SourceGit.Views
                         }
                     }
 
-                    UpdateGrammar();
+                    Models.TextMateHelper.SetGrammarByFileName(_textMate, DiffData.File);
                     Text = builder.ToString();
                 }
                 else
@@ -744,37 +703,14 @@ namespace SourceGit.Views
                     }
                 }
             }
-            else if (change.Property.Name == "ActualThemeVariant" && change.NewValue != null && _textMate != null)
+            else if (change.Property.Name == "ActualThemeVariant" && change.NewValue != null)
             {
-                if (App.Current?.ActualThemeVariant == ThemeVariant.Dark)
+                Models.TextMateHelper.SetThemeByApp(_textMate);
-                {
-                    _textMate.SetTheme(_registryOptions.LoadTheme(ThemeName.DarkPlus));
-                }
-                else
-                {
-                    _textMate.SetTheme(_registryOptions.LoadTheme(ThemeName.LightPlus));
-                }
             }
         }
 
-        private void UpdateGrammar()
-        {
-            if (_textMate == null || DiffData == null) return;
-
-            var ext = Path.GetExtension(DiffData.File);
-            if (ext == ".h")
-            {
-                _textMate.SetGrammar(_registryOptions.GetScopeByLanguageId("cpp"));
-            }
-            else
-            {
-                _textMate.SetGrammar(_registryOptions.GetScopeByExtension(ext));
-            }
-        }
-
-        private RegistryOptions _registryOptions;
         private TextMate.Installation _textMate;
-
+        private LineStyleTransformer _lineStyleTransformer = null;
         private ScrollViewer _scrollViewer = null;
         private bool _syncScrollingByOthers = false;
     }