ux: use a new resource Brush.Diff.BlockBorderHighlight to highlight current block in text diff view (#2113)

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

Author: love-linger

src/Resources/Themes.axaml

@@ -27,6 +27,7 @@
       <Color x:Key="Color.Diff.DeletedBG">#80FF9797</Color>
       <Color x:Key="Color.Diff.AddedHighlight">#A7E1A7</Color>
       <Color x:Key="Color.Diff.DeletedHighlight">#F19B9D</Color>
+      <Color x:Key="Color.Diff.BlockBorderHighlight">DarkCyan</Color>
       <Color x:Key="Color.Link">#0000EE</Color>
       <Color x:Key="Color.InlineCode">#FFE4E4E4</Color>
       <Color x:Key="Color.InlineCodeFG">Black</Color>
@@ -59,6 +60,7 @@
       <Color x:Key="Color.Diff.DeletedBG">#C0633F3E</Color>
       <Color x:Key="Color.Diff.AddedHighlight">#A0308D3C</Color>
       <Color x:Key="Color.Diff.DeletedHighlight">#A09F4247</Color>
+      <Color x:Key="Color.Diff.BlockBorderHighlight">DarkCyan</Color>
       <Color x:Key="Color.Link">#4DAAFC</Color>
       <Color x:Key="Color.InlineCode">#FF383838</Color>
       <Color x:Key="Color.InlineCodeFG">#FFF0F0F0</Color>
@@ -93,6 +95,7 @@
   <SolidColorBrush x:Key="Brush.Diff.DeletedBG" Color="{DynamicResource Color.Diff.DeletedBG}"/>
   <SolidColorBrush x:Key="Brush.Diff.AddedHighlight" Color="{DynamicResource Color.Diff.AddedHighlight}"/>
   <SolidColorBrush x:Key="Brush.Diff.DeletedHighlight" Color="{DynamicResource Color.Diff.DeletedHighlight}"/>
+  <SolidColorBrush x:Key="Brush.Diff.BlockBorderHighlight" Color="{DynamicResource Color.Diff.BlockBorderHighlight}"/>
   <SolidColorBrush x:Key="Brush.Link" Color="{DynamicResource Color.Link}"/>
   <SolidColorBrush x:Key="Brush.InlineCode" Color="{DynamicResource Color.InlineCode}"/>
   <SolidColorBrush x:Key="Brush.InlineCodeFG" Color="{DynamicResource Color.InlineCodeFG}"/>

src/Views/TextDiffView.axaml

@@ -23,6 +23,7 @@
                                          AddedHighlightBrush="{DynamicResource Brush.Diff.AddedHighlight}"
                                          DeletedHighlightBrush="{DynamicResource Brush.Diff.DeletedHighlight}"
                                          IndicatorForeground="{DynamicResource Brush.FG2}"
+                                         BlockBorderHighlightBrush="{DynamicResource Brush.Diff.BlockBorderHighlight}"
                                          FontFamily="{DynamicResource Fonts.Monospace}"
                                          FontSize="{Binding Source={x:Static vm:Preferences.Instance}, Path=EditorFontSize}"
                                          TabWidth="{Binding Source={x:Static vm:Preferences.Instance}, Path=EditorTabWidth}"
@@ -54,6 +55,7 @@
                                            AddedHighlightBrush="{DynamicResource Brush.Diff.AddedHighlight}"
                                            DeletedHighlightBrush="{DynamicResource Brush.Diff.DeletedHighlight}"
                                            IndicatorForeground="{DynamicResource Brush.FG2}"
+                                           BlockBorderHighlightBrush="{DynamicResource Brush.Diff.BlockBorderHighlight}"
                                            FontFamily="{DynamicResource Fonts.Monospace}"
                                            FontSize="{Binding Source={x:Static vm:Preferences.Instance}, Path=EditorFontSize}"
                                            TabWidth="{Binding Source={x:Static vm:Preferences.Instance}, Path=EditorTabWidth}"
@@ -76,6 +78,7 @@
                                            AddedHighlightBrush="{DynamicResource Brush.Diff.AddedHighlight}"
                                            DeletedHighlightBrush="{DynamicResource Brush.Diff.DeletedHighlight}"
                                            IndicatorForeground="{DynamicResource Brush.FG2}"
+                                           BlockBorderHighlightBrush="{DynamicResource Brush.Diff.BlockBorderHighlight}"
                                            FontFamily="{DynamicResource Fonts.Monospace}"
                                            FontSize="{Binding Source={x:Static vm:Preferences.Instance}, Path=EditorFontSize}"
                                            TabWidth="{Binding Source={x:Static vm:Preferences.Instance}, Path=EditorTabWidth}"

src/Views/TextDiffView.axaml.cs

@@ -216,8 +216,7 @@ public void Draw(TextView textView, DrawingContext drawingContext)
                     return;
 
                 var changeBlock = _presenter.BlockNavigation.GetCurrentBlock();
-                var changeBlockBG = new SolidColorBrush(Colors.Gray, 0.25);
-                var changeBlockFG = new Pen(Brushes.Gray);
+                var changeBlockBorder = new Pen(_presenter.BlockBorderHighlightBrush);
 
                 var lines = _presenter.GetLines();
                 var width = textView.Bounds.Width;
@@ -279,14 +278,14 @@ public void Draw(TextView textView, DrawingContext drawingContext)
                         }
                     }
 
-                    if (changeBlock != null && changeBlock.Contains(index))
-                    {
-                        drawingContext.DrawRectangle(changeBlockBG, null, new Rect(0, startY, width, endY - startY));
-                        if (index == changeBlock.Start)
-                            drawingContext.DrawLine(changeBlockFG, new Point(0, startY), new Point(width, startY));
-                        if (index == changeBlock.End)
-                            drawingContext.DrawLine(changeBlockFG, new Point(0, endY), new Point(width, endY));
-                    }
+                    if (changeBlock == null)
+                        continue;
+
+                    if (index == changeBlock.Start)
+                        drawingContext.DrawLine(changeBlockBorder, new Point(0, startY), new Point(width, startY));
+
+                    if (index == changeBlock.End)
+                        drawingContext.DrawLine(changeBlockBorder, new Point(0, endY), new Point(width, endY));
                 }
             }
 
@@ -406,6 +405,15 @@ public IBrush IndicatorForeground
             set => SetValue(IndicatorForegroundProperty, value);
         }
 
+        public static readonly StyledProperty<IBrush> BlockBorderHighlightBrushProperty =
+            AvaloniaProperty.Register<ThemedTextDiffPresenter, IBrush>(nameof(BlockBorderHighlightBrush), Brushes.Gray);
+
+        public IBrush BlockBorderHighlightBrush
+        {
+            get => GetValue(BlockBorderHighlightBrushProperty);
+            set => SetValue(BlockBorderHighlightBrushProperty, value);
+        }
+
         public static readonly StyledProperty<bool> UseSyntaxHighlightingProperty =
             AvaloniaProperty.Register<ThemedTextDiffPresenter, bool>(nameof(UseSyntaxHighlighting));