refactor: implementation of synchronous scrolling in side-by-side diff view

Author: love-linger

src/Models/DiffResult.cs

@@ -388,11 +388,11 @@ public void GeneratePatchFromSelectionSingleSide(Change change, string fileTreeG
         }
 
         [GeneratedRegex(@"^@@ \-(\d+),?\d* \+(\d+),?\d* @@")]
-        private static partial Regex indicatorRegex();
+        private static partial Regex REG_INDICATOR();
 
         private bool ProcessIndicatorForPatch(StringBuilder builder, TextDiffLine indicator, int idx, int start, int end, int ignoreRemoves, int ignoreAdds, bool revert, bool tailed)
         {
-            var match = indicatorRegex().Match(indicator.Content);
+            var match = REG_INDICATOR().Match(indicator.Content);
             var oldStart = int.Parse(match.Groups[1].Value);
             var newStart = int.Parse(match.Groups[2].Value) + ignoreRemoves - ignoreAdds;
             var oldCount = 0;
@@ -461,7 +461,7 @@ private bool ProcessIndicatorForPatch(StringBuilder builder, TextDiffLine indica
 
         private bool ProcessIndicatorForPatchSingleSide(StringBuilder builder, TextDiffLine indicator, int idx, int start, int end, int ignoreRemoves, int ignoreAdds, bool revert, bool isOldSide, bool tailed)
         {
-            var match = indicatorRegex().Match(indicator.Content);
+            var match = REG_INDICATOR().Match(indicator.Content);
             var oldStart = int.Parse(match.Groups[1].Value);
             var newStart = int.Parse(match.Groups[2].Value) + ignoreRemoves - ignoreAdds;
             var oldCount = 0;

src/Views/TextDiffView.axaml.cs

@@ -7,6 +7,7 @@
 using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Controls.Primitives;
+using Avalonia.Input;
 using Avalonia.Interactivity;
 using Avalonia.Media;
 using Avalonia.VisualTree;
@@ -657,6 +658,7 @@ protected override void OnLoaded(RoutedEventArgs e)
 
             UpdateTextMate();
 
+            TextArea.PointerWheelChanged += OnTextAreaPointerWheelChanged;
             TextArea.TextView.ContextRequested += OnTextViewContextRequested;
         }
 
@@ -676,21 +678,20 @@ protected override void OnUnloaded(RoutedEventArgs e)
                 _textMate = null;
             }
 
+            TextArea.PointerWheelChanged -= OnTextAreaPointerWheelChanged;
             TextArea.TextView.ContextRequested -= OnTextViewContextRequested;
 
             GC.Collect();
         }
 
+        private void OnTextAreaPointerWheelChanged(object sender, PointerWheelEventArgs e)
+        {
+            if (!TextArea.IsFocused) Focus();
+        }
+
         private void OnTextViewScrollChanged(object sender, ScrollChangedEventArgs e)
         {
-            if (_syncScrollingByOthers)
-            {
-                _syncScrollingByOthers = false;
-            }
-            else
-            {
-                SetCurrentValue(SyncScrollOffsetProperty, _scrollViewer.Offset);
-            }
+            if (TextArea.IsFocused) SetCurrentValue(SyncScrollOffsetProperty, _scrollViewer.Offset);
         }
 
         private void OnTextViewContextRequested(object sender, ContextRequestedEventArgs e)
@@ -754,24 +755,8 @@ protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs chang
             }
             else if (change.Property == SyncScrollOffsetProperty)
             {
-                if (_scrollViewer == null)
-                    return;
-
-                var curOffset = _scrollViewer.Offset;
-                if (!curOffset.Equals(SyncScrollOffset))
-                {
-                    _syncScrollingByOthers = true;
-
-                    if (curOffset.X != SyncScrollOffset.X)
-                    {
-                        var offset = new Vector(Math.Min(_scrollViewer.ScrollBarMaximum.X, SyncScrollOffset.X), SyncScrollOffset.Y);
-                        _scrollViewer.Offset = offset;
-                    }
-                    else
-                    {
-                        _scrollViewer.Offset = SyncScrollOffset;
-                    }
-                }
+                if (_scrollViewer != null)
+                    _scrollViewer.Offset = SyncScrollOffset;
             }
             else if (change.Property == UseSyntaxHighlightingProperty)
             {
@@ -813,7 +798,6 @@ private void UpdateTextMate()
         private TextMate.Installation _textMate;
         private readonly LineStyleTransformer _lineStyleTransformer = null;
         private ScrollViewer _scrollViewer = null;
-        private bool _syncScrollingByOthers = false;
     }
 
     public partial class TextDiffView : UserControl