feature: allow to scroll text diff view to clicked position in minimap bar (#1679)

Signed-off-by: leo <longshuang@msn.cn>

Author: love-linger

src/Views/TextDiffView.axaml

@@ -12,7 +12,7 @@
     <ContentControl Content="{Binding}">
       <ContentControl.DataTemplates>
         <DataTemplate DataType="vm:CombinedTextDiff">
-          <Grid ColumnDefinitions="*,1,8">
+          <Grid ColumnDefinitions="*,1,12">
             <v:CombinedTextDiffPresenter Grid.Column="0"
                                          FileName="{Binding File}"
                                          Foreground="{DynamicResource Brush.FG1}"

src/Views/TextDiffView.axaml.cs

@@ -1334,6 +1334,8 @@ static TextDiffViewMinimap()
 
         public override void Render(DrawingContext context)
         {
+            context.DrawRectangle(Brushes.Transparent, null, new Rect(0, 0, Bounds.Width, Bounds.Height));
+
             var total = 0;
             if (DataContext is ViewModels.TwoSideTextDiff twoSideDiff)
             {
@@ -1371,6 +1373,42 @@ protected override void OnDataContextChanged(EventArgs e)
             InvalidateVisual();
         }
 
+        protected override void OnPointerPressed(PointerPressedEventArgs e)
+        {
+            base.OnPointerPressed(e);
+
+            var range = DisplayRange;
+            if (range == null || range.End == 0)
+                return;
+
+            var total = 0;
+            if (DataContext is ViewModels.TwoSideTextDiff twoSideDiff)
+            {
+                var halfWidth = Bounds.Width * 0.5;
+                total = Math.Max(twoSideDiff.Old.Count, twoSideDiff.New.Count);
+            }
+            else if (DataContext is ViewModels.CombinedTextDiff combined)
+            {
+                var data = combined.Data;
+                total = data.Lines.Count;
+            }
+            else
+            {
+                return;
+            }
+
+            var height = Bounds.Height;
+            var startY = range.Start / (total * 1.0) * height;
+            var endY = range.End / (total * 1.0) * height;
+            var pressedY = e.GetPosition(this).Y;
+            if (pressedY >= startY && pressedY <= endY)
+                return;
+
+            var line = Math.Max(1, Math.Min(total, (int)Math.Ceiling(pressedY * total / height)));
+            this.FindAncestorOfType<TextDiffView>()?.ScrollToLine(line);
+            e.Handled = true;
+        }
+
         private void RenderSingleSide(DrawingContext context, List<Models.TextDiffLine> lines, double x, double width)
         {
             var total = lines.Count;
@@ -1414,11 +1452,17 @@ public ViewModels.TextDiffSelectedChunk SelectedChunk
             get => GetValue(SelectedChunkProperty);
             set => SetValue(SelectedChunkProperty, value);
         }
+
         public TextDiffView()
         {
             InitializeComponent();
         }
 
+        public void ScrollToLine(int line)
+        {
+            this.FindDescendantOfType<ThemedTextDiffPresenter>()?.ScrollToLine(line);
+        }
+
         protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs change)
         {
             base.OnPropertyChanged(change);