fix: improve branch colors in the commit graph

src/Models/Commit.cs

@@ -25,7 +25,11 @@ public class Commit : ObservableObject
         public List<Decorator> Decorators { get; set; } = new();
 
         public bool IsMerged { get; set; } = false;
-        public int Color { get; set; } = 0;
+        public int Color
+        {
+            get => _color;
+            set => SetProperty(ref _color, value);
+        }
         public double LeftMargin { get; set; } = 0;
 
         public bool IsHighlightedInGraph
@@ -125,6 +129,7 @@ public void ParseDecorators(string data)
             });
         }
 
+        private int _color = 0;
         private bool _isHighlightedInGraph = false;
     }
 

src/Models/CommitGraph.cs

@@ -34,6 +34,8 @@ public static void SetPens(List<Color> colors, double thickness)
                 Pens.Add(new Pen(c.ToUInt32(), thickness));
 
             s_penCount = colors.Count;
+            for (var i = 1; i < Bookmarks.Brushes.Length; i++)
+                Pens.Add(new Pen(Bookmarks.Brushes[i], thickness));
         }
 
         public class Path(int color, bool isHighlighted)
@@ -71,7 +73,7 @@ public class Dot
         public List<Link> Links { get; } = [];
         public List<Dot> Dots { get; } = [];
 
-        public static CommitGraph Generate(List<Commit> commits, bool firstParentOnlyEnabled, CommitGraphHighlighting highlighting, HashSet<string> highlightExtraCommits)
+        public static CommitGraph Generate(List<Commit> commits, bool firstParentOnlyEnabled, CommitGraphHighlighting highlighting, HashSet<string> highlightExtraCommits, int bookmark = 0)
         {
             const double unitWidth = 12;
             const double halfWidth = 6;
@@ -82,12 +84,14 @@ public static CommitGraph Generate(List<Commit> commits, bool firstParentOnlyEna
             var unsolved = new List<PathHelper>();
             var ended = new List<PathHelper>();
             var offsetY = -halfHeight;
-            var colorPicker = new ColorPicker();
+            var headColor = commits.Exists(x => x.IsCurrentHead) ? GetBookmarkColor(bookmark) : -1;
+            var colorPicker = new ColorPicker(headColor);
             var defHighlighting = highlighting == CommitGraphHighlighting.All;
 
             foreach (var commit in commits)
             {
                 PathHelper major = null;
+                var isBookmarkedHead = commit.IsCurrentHead && headColor >= 0;
 
                 // Update current y offset
                 offsetY += unitHeight;
@@ -184,7 +188,8 @@ public static CommitGraph Generate(List<Commit> commits, bool firstParentOnlyEna
 
                     if (commit.Parents.Count > 0)
                     {
-                        major = new PathHelper(commit.Parents[0], isHighlighted, colorPicker.Next(), new Point(offsetX, offsetY));
+                        var color = isBookmarkedHead ? headColor : colorPicker.Next();
+                        major = new PathHelper(commit.Parents[0], isHighlighted, color, new Point(offsetX, offsetY));
                         unsolved.Add(major);
                         temp.Paths.Add(major.Path);
                     }
@@ -195,9 +200,37 @@ public static CommitGraph Generate(List<Commit> commits, bool firstParentOnlyEna
                     temp.Paths.Add(major.Path);
                 }
 
+                var hasBranch = commit.Decorators.Exists(x => x.Type is DecoratorType.CurrentBranchHead or DecoratorType.LocalBranchHead or DecoratorType.RemoteBranchHead);
+                if (major != null && hasBranch)
+                {
+                    if (major.HasBranch && !isBookmarkedHead)
+                    {
+                        // A named branch can start on an existing line without a fork.
+                        // Split its color at the branch tip, preserving the lane and highlighting.
+                        var oldColor = major.Path.Color;
+                        var color = colorPicker.Next(oldColor);
+                        if (color != oldColor)
+                        {
+                            major.ChangeColor(color);
+                            if (commit.Parents.Count > 0)
+                                temp.Paths.Add(major.Path);
+                        }
+                        colorPicker.Recycle(commit.Parents.Count > 0 ? oldColor : color);
+                    }
+                    major.HasBranch = true;
+                }
+
+                if (isBookmarkedHead && major != null && major.Path.Color != headColor)
+                {
+                    colorPicker.Recycle(major.Path.Color);
+                    major.ChangeColor(headColor);
+                    if (commit.Parents.Count > 0)
+                        temp.Paths.Add(major.Path);
+                }
+
                 // Calculate link position of this commit.
                 var position = new Point(major?.LastX ?? offsetX, offsetY);
-                var dotColor = major?.Path.Color ?? 0;
+                var dotColor = major?.Path.Color ?? (isBookmarkedHead ? headColor : 0);
                 var anchor = new Dot() { Center = position, Color = dotColor, IsHighlighted = isHighlighted };
                 if (commit.IsCurrentHead)
                     anchor.Type = DotType.Head;
@@ -268,22 +301,44 @@ public static CommitGraph Generate(List<Commit> commits, bool firstParentOnlyEna
             return temp;
         }
 
-        private class ColorPicker
+        private static int GetBookmarkColor(int bookmark)
         {
-            public int Next()
+            if (Bookmarks.Get(bookmark) is not ISolidColorBrush brush)
+                return -1;
+
+            for (var i = 0; i < s_penCount; i++)
             {
-                if (_colorsQueue.Count == 0)
+                if (Pens[i].Brush is ISolidColorBrush graphBrush && graphBrush.Color == brush.Color)
+                    return i;
+            }
+
+            return s_penCount + bookmark - 1;
+        }
+
+        private class ColorPicker(int reservedColor)
+        {
+            public int Next(int exclude = -1)
+            {
+                var reservedCount = s_penCount > 1 && reservedColor >= 0 && reservedColor < s_penCount ? 1 : 0;
+                int color;
+                do
                 {
-                    for (var i = 0; i < s_penCount; i++)
-                        _colorsQueue.Enqueue(i);
+                    if (_colorsQueue.Count == 0)
+                    {
+                        for (var i = 0; i < s_penCount; i++)
+                            _colorsQueue.Enqueue(i);
+                    }
+
+                    color = _colorsQueue.Dequeue();
                 }
+                while ((reservedCount > 0 && color == reservedColor) || (s_penCount - reservedCount > 1 && color == exclude));
 
-                return _colorsQueue.Dequeue();
+                return color;
             }
 
             public void Recycle(int idx)
             {
-                if (!_colorsQueue.Contains(idx))
+                if (idx < s_penCount && idx != reservedColor && !_colorsQueue.Contains(idx))
                     _colorsQueue.Enqueue(idx);
             }
 
@@ -292,6 +347,7 @@ public void Recycle(int idx)
 
         private class PathHelper
         {
+            public bool HasBranch { get; set; }
             public Path Path { get; private set; }
             public string Next { get; set; }
             public double LastX { get; private set; }
@@ -398,10 +454,19 @@ public void End(double x, double y, double halfHeight)
             /// </summary>
             public void Highlight()
             {
-                var color = Path.Color;
+                Restart(Path.Color, true);
+            }
+
+            public void ChangeColor(int color)
+            {
+                Restart(color, Path.IsHighlighted);
+            }
+
+            private void Restart(int color, bool isHighlighted)
+            {
                 Add(LastX, _lastY);
 
-                Path = new Path(color, true);
+                Path = new Path(color, isHighlighted);
                 Path.Points.Add(new Point(LastX, _lastY));
                 _endY = 0;
             }

src/ViewModels/Histories.cs

@@ -567,6 +567,11 @@ private void PostSelectedCommitsChanged()
                 GenerateGraph(_commits);
         }
 
+        public void RefreshGraph()
+        {
+            GenerateGraph(_commits);
+        }
+
         private void GenerateGraph(List<Models.Commit> commits)
         {
             var firstParentOnly = _repo.UIStates.HistoryShowFlags.HasFlag(Models.HistoryShowFlags.FirstParentOnly);
@@ -579,7 +584,7 @@ private void GenerateGraph(List<Models.Commit> commits)
                     extraHeads.Add(c.SHA);
             }
 
-            Graph = Models.CommitGraph.Generate(commits, firstParentOnly, highlighting, extraHeads);
+            Graph = Models.CommitGraph.Generate(commits, firstParentOnly, highlighting, extraHeads, _repo.Bookmark);
         }
 
         private Repository _repo = null;

src/ViewModels/Repository.cs

@@ -29,6 +29,8 @@ public string GitDir
             get;
         }
 
+        public int Bookmark => GetOwnerPage()?.Node.Bookmark ?? Preferences.Instance.FindNode(FullPath)?.Bookmark ?? 0;
+
         public Models.RepositorySettings Settings
         {
             get => _settings;

src/ViewModels/RepositoryNode.cs

@@ -36,7 +36,17 @@ public string Name
         public int Bookmark
         {
             get => _bookmark;
-            set => SetProperty(ref _bookmark, value);
+            set
+            {
+                if (!SetProperty(ref _bookmark, value) || App.GetLauncher() is not { } launcher)
+                    return;
+
+                foreach (var page in launcher.Pages)
+                {
+                    if (ReferenceEquals(page.Node, this) && page.Data is Repository repo)
+                        repo.Histories?.RefreshGraph();
+                }
+            }
         }
 
         public bool IsRepository

src/Views/CommitRefsPresenter.cs

@@ -139,6 +139,15 @@ public bool UseGraphColor
             set => SetValue(UseGraphColorProperty, value);
         }
 
+        public static readonly StyledProperty<int> GraphColorProperty =
+            AvaloniaProperty.Register<CommitRefsPresenter, int>(nameof(GraphColor), -1);
+
+        public int GraphColor
+        {
+            get => GetValue(GraphColorProperty);
+            set => SetValue(GraphColorProperty, value);
+        }
+
         public static readonly StyledProperty<bool> AllowWrapProperty =
             AvaloniaProperty.Register<CommitRefsPresenter, bool>(nameof(AllowWrap));
 
@@ -260,6 +269,7 @@ protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs chang
                 change.Property == FontSizeProperty ||
                 change.Property == ForegroundProperty ||
                 change.Property == UseGraphColorProperty ||
+                change.Property == GraphColorProperty ||
                 change.Property == UseCompactBranchNamesProperty ||
                 change.Property == HasSingleRemoteProperty ||
                 change.Property == BackgroundProperty ||
@@ -294,7 +304,7 @@ protected override Size MeasureOverride(Size availableSize)
             var typefaceHead = new Typeface(FontFamily, FontStyle.Normal, FontWeight.Bold);
             var typefaceRemote = new Typeface(FontFamily, FontStyle.Italic, FontWeight.Bold);
             var fg = Foreground;
-            var normalBG = UseGraphColor ? Models.CommitGraph.Pens[commit.Color].Brush : Brushes.Gray;
+            var normalBG = UseGraphColor ? Models.CommitGraph.Pens[GraphColor >= 0 ? GraphColor : commit.Color].Brush : Brushes.Gray;
             var labelSize = FontSize;
             var requiredHeight = 16.0;
             var x = 0.0;

src/Views/Histories.axaml

@@ -133,6 +133,7 @@
                                            FontSize="12"
                                            VerticalAlignment="Center"
                                            UseGraphColor="{Binding IsHighlightedInGraph, Mode=OneWay}"
+                                           GraphColor="{Binding Color, Mode=OneWay}"
                                            UseCompactBranchNames="{Binding Source={x:Static vm:Preferences.Instance}, Path=UseCompactBranchNamesInGraph}"
                                            HasSingleRemote="{Binding $parent[v:Histories].HasSingleRemote}"/>
 

tests/BookmarkBranchColorChecks/BookmarkBranchColorChecks.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+  </PropertyGroup>
+  <ItemGroup>
+    <ProjectReference Include="../../src/SourceGit.csproj" />
+  </ItemGroup>
+</Project>