feature: add focused history layout

src/Models/HistoryLayout.cs

@@ -0,0 +1,9 @@
+namespace SourceGit.Models
+{
+    public enum HistoryLayout
+    {
+        Stacked,
+        SideBySide,
+        Focused,
+    }
+}

src/Models/RepositoryUIStates.cs

@@ -45,6 +45,12 @@ public double AuthorColumnWidth
             set;
         } = 120;
 
+        public double FocusedHistoryDetailsWidth
+        {
+            get;
+            set;
+        } = 340;
+
         public bool EnableTopoOrderInHistory
         {
             get;

src/Resources/Locales/en_US.axaml

@@ -515,6 +515,8 @@
   <x:String x:Key="Text.GitLFS.TrackByExtension" xml:space="preserve">Track all *{0} files</x:String>
   <x:String x:Key="Text.GotoRevisionSelector" xml:space="preserve">Select Commit</x:String>
   <x:String x:Key="Text.Histories.AdvancedOptions" xml:space="preserve">Advanced Options</x:String>
+  <x:String x:Key="Text.Histories.BackToGraph" xml:space="preserve">← Graph</x:String>
+  <x:String x:Key="Text.Histories.CopyCommitSHA" xml:space="preserve">Copy full commit SHA</x:String>
   <x:String x:Key="Text.Histories.Header.Author" xml:space="preserve">AUTHOR</x:String>
   <x:String x:Key="Text.Histories.Header.AuthorTime" xml:space="preserve">AUTHOR TIME</x:String>
   <x:String x:Key="Text.Histories.Header.CommitTime" xml:space="preserve">COMMIT TIME</x:String>
@@ -527,6 +529,7 @@
   <x:String x:Key="Text.Histories.HighlightsInGraph.SelectedCommitsOnly" xml:space="preserve">Selected Commits Only</x:String>
   <x:String x:Key="Text.Histories.HighlightsInGraph.SelectedCommitsOnlyFirstParent" xml:space="preserve">Selected Commits (First-parent Only)</x:String>
   <x:String x:Key="Text.Histories.Selected" xml:space="preserve">SELECTED {0} COMMITS</x:String>
+  <x:String x:Key="Text.Histories.SelectionDetails" xml:space="preserve">DETAILS</x:String>
   <x:String x:Key="Text.Histories.ShowColumns" xml:space="preserve">SHOW COLUMNS</x:String>
   <x:String x:Key="Text.Histories.Tips" xml:space="preserve">Hold 'Ctrl' or 'Shift' to select multiple commits.</x:String>
   <x:String x:Key="Text.Histories.Tips.MacOS" xml:space="preserve">Hold ⌘ or ⇧ to select multiple commits.</x:String>
@@ -822,6 +825,7 @@
   <x:String x:Key="Text.Repository.FilterCommits.Include" xml:space="preserve">Filter in commit graph</x:String>
   <x:String x:Key="Text.Repository.FilterCommits.Summary" xml:space="preserve">filter(s) enabled</x:String>
   <x:String x:Key="Text.Repository.HistoriesLayout" xml:space="preserve">LAYOUT</x:String>
+  <x:String x:Key="Text.Repository.HistoriesLayout.Focused" xml:space="preserve">Focused</x:String>
   <x:String x:Key="Text.Repository.HistoriesLayout.Horizontal" xml:space="preserve">Horizontal</x:String>
   <x:String x:Key="Text.Repository.HistoriesLayout.Vertical" xml:space="preserve">Vertical</x:String>
   <x:String x:Key="Text.Repository.HistoriesOrder" xml:space="preserve">COMMITS ORDER</x:String>

src/ViewModels/CommitDetail.cs

@@ -539,9 +539,9 @@ private void Refresh()
             }, token);
         }
 
-        private void UpdateDetails()
+        public void UpdateDetails()
         {
-            if (ActiveTabIndex == 1 && _changeSelection is { Count: 1, HasFolder: false })
+            if ((ActiveTabIndex == 1 || Preferences.Instance.IsFocusedHistoryLayout) && _changeSelection is { Count: 1, HasFolder: false })
                 DiffContext = new DiffContext(_repo.FullPath, new Models.DiffOption(_commit, _changeSelection.Changes[0]), _diffContext);
             else
                 DiffContext = null;

src/ViewModels/Histories.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel;
 using System.IO;
 using System.Threading.Tasks;
 
@@ -149,10 +150,92 @@ public object DetailContext
             set
             {
                 if (SetProperty(ref _detailContext, value))
+                {
+                    ShowGraph();
+                    ObserveDetailContext(value);
                     OnPropertyChanged(nameof(IsOpenAsStandaloneVisible));
+                }
+            }
+        }
+
+        public DiffContext FocusedDiff
+        {
+            get => _focusedDiff;
+            private set
+            {
+                if (SetProperty(ref _focusedDiff, value))
+                    OnPropertyChanged(nameof(IsFocusedDiffVisible));
             }
         }
 
+        public string FocusedDiffPath
+        {
+            get => _focusedDiffPath;
+            private set => SetProperty(ref _focusedDiffPath, value);
+        }
+
+        public bool IsFocusedDiffVisible => Preferences.Instance.IsFocusedHistoryLayout && FocusedDiff != null;
+
+        public void OpenFocusedDiff()
+        {
+            if (!Preferences.Instance.IsFocusedHistoryLayout)
+                return;
+
+            ChangeSelection selection;
+            DiffContext diff;
+            if (DetailContext is CommitDetail detail)
+            {
+                selection = detail.ChangeSelection;
+                if (detail.DiffContext == null)
+                    detail.UpdateDetails();
+                diff = detail.DiffContext;
+            }
+            else if (DetailContext is RevisionCompare compare)
+            {
+                selection = compare.ChangeSelection;
+                diff = compare.DiffContext;
+            }
+            else
+            {
+                return;
+            }
+
+            if (selection is { Count: 1, HasFolder: false } && diff != null)
+            {
+                FocusedDiffPath = selection.Changes[0].Path;
+                FocusedDiff = diff;
+            }
+        }
+
+        public void ShowGraph()
+        {
+            FocusedDiff = null;
+            FocusedDiffPath = string.Empty;
+        }
+
+        public void UpdateLayout()
+        {
+            ShowGraph();
+            OnPropertyChanged(nameof(RightArea));
+            OnPropertyChanged(nameof(BottomArea));
+        }
+
+        private void ObserveDetailContext(object context)
+        {
+            if (_observedDetailContext != null)
+                _observedDetailContext.PropertyChanged -= OnDetailContextPropertyChanged;
+            _observedDetailContext = context as INotifyPropertyChanged;
+            if (_observedDetailContext != null)
+                _observedDetailContext.PropertyChanged += OnDetailContextPropertyChanged;
+        }
+
+        private void OnDetailContextPropertyChanged(object sender, PropertyChangedEventArgs e)
+        {
+            if (e.PropertyName is nameof(CommitDetail.Commit) or nameof(RevisionCompare.IsLoading) or
+                nameof(RevisionCompare.StartPoint) or nameof(RevisionCompare.EndPoint))
+                ShowGraph();
+        }
+
         public Models.Bisect Bisect
         {
             get => _bisect;
@@ -184,8 +267,20 @@ public GridLength LeftArea
 
         public GridLength RightArea
         {
-            get => _rightArea;
-            set => SetProperty(ref _rightArea, value);
+            get => Preferences.Instance.IsFocusedHistoryLayout ? new GridLength(_repo.UIStates.FocusedHistoryDetailsWidth) : _rightArea;
+            set
+            {
+                if (Preferences.Instance.IsFocusedHistoryLayout)
+                {
+                    if (value.IsAbsolute && value.Value >= 260)
+                    {
+                        _repo.UIStates.FocusedHistoryDetailsWidth = value.Value;
+                        OnPropertyChanged();
+                    }
+                }
+                else
+                    SetProperty(ref _rightArea, value);
+            }
         }
 
         public GridLength TopArea
@@ -199,7 +294,7 @@ public GridLength BottomArea
             get => _isCollapseDetails ? new GridLength(28, GridUnitType.Pixel) : _bottomArea;
             set
             {
-                if (!Preferences.Instance.UseTwoColumnsLayoutInHistories && !_isCollapseDetails)
+                if (!Preferences.Instance.IsHorizontalHistoryLayout && !_isCollapseDetails)
                     SetProperty(ref _bottomArea, value);
             }
         }
@@ -220,7 +315,7 @@ public bool IsCollapseDetails
             get => _isCollapseDetails;
             set
             {
-                if (!Preferences.Instance.UseTwoColumnsLayoutInHistories && SetProperty(ref _isCollapseDetails, value))
+                if (!Preferences.Instance.IsHorizontalHistoryLayout && SetProperty(ref _isCollapseDetails, value))
                 {
                     OnPropertyChanged(nameof(TopArea));
                     OnPropertyChanged(nameof(BottomArea));
@@ -588,6 +683,9 @@ private void GenerateGraph(List<Models.Commit> commits)
         private Models.Bisect _bisect = null;
         private object _detailContext = Models.Null.Instance;
         private bool _ignoreSelectionChange = false;
+        private INotifyPropertyChanged _observedDetailContext = null;
+        private DiffContext _focusedDiff = null;
+        private string _focusedDiffPath = string.Empty;
 
         private bool _isSearchingCommits = false;
         private SearchCommitContext _searchCommitContext = null;

src/ViewModels/Preferences.cs

@@ -213,8 +213,40 @@ public bool UseCompactBranchNamesInGraph
 
         public bool UseTwoColumnsLayoutInHistories
         {
-            get => _useTwoColumnsLayoutInHistories;
-            set => SetProperty(ref _useTwoColumnsLayoutInHistories, value);
+            get => IsHorizontalHistoryLayout;
+            set
+            {
+                // Keep reading older preference files. The explicit layout takes precedence,
+                // regardless of the order of properties in the JSON document.
+                if (SetProperty(ref _useTwoColumnsLayoutInHistories, value) && !_historyLayout.HasValue)
+                    NotifyHistoryLayoutChanged();
+            }
+        }
+
+        public Models.HistoryLayout HistoryLayout
+        {
+            get => _historyLayout ?? (_useTwoColumnsLayoutInHistories ? Models.HistoryLayout.SideBySide : Models.HistoryLayout.Stacked);
+            set
+            {
+                if (Enum.IsDefined(value) && _historyLayout != value)
+                {
+                    _historyLayout = value;
+                    NotifyHistoryLayoutChanged();
+                }
+            }
+        }
+
+        [JsonIgnore]
+        public bool IsHorizontalHistoryLayout => HistoryLayout != Models.HistoryLayout.Stacked;
+
+        [JsonIgnore]
+        public bool IsFocusedHistoryLayout => HistoryLayout == Models.HistoryLayout.Focused;
+
+        private void NotifyHistoryLayoutChanged()
+        {
+            OnPropertyChanged(nameof(HistoryLayout));
+            OnPropertyChanged(nameof(IsHorizontalHistoryLayout));
+            OnPropertyChanged(nameof(IsFocusedHistoryLayout));
         }
 
         public bool DisplayTimeAsPeriodInHistories
@@ -831,6 +863,7 @@ private bool RemoveInvalidRepositoriesRecursive(List<RepositoryNode> collection)
 
         private bool _showTagsInGraph = true;
         private bool _useTwoColumnsLayoutInHistories = false;
+        private Models.HistoryLayout? _historyLayout = null;
         private bool _displayTimeAsPeriodInHistories = false;
         private bool _useSideBySideDiff = false;
         private bool _ignoreWhitespaceChangesInDiff = false;

src/ViewModels/RevisionCompare.cs

@@ -121,8 +121,8 @@ _endPoint is Models.Commit e &&
                 hashes.Contains(e.SHA))
                 return;
 
-            _startPoint = l;
-            _endPoint = r;
+            StartPoint = l;
+            EndPoint = r;
             Refresh();
         }
 
@@ -343,6 +343,9 @@ private void RefreshVisible()
 
         private void Refresh()
         {
+            OnPropertyChanged(nameof(LeftSideDesc));
+            OnPropertyChanged(nameof(RightSideDesc));
+
             Task.Run(async () =>
             {
                 _changes = await new Commands.CompareRevisions(_repo.FullPath, GetSHA(_startPoint), GetSHA(_endPoint))

src/Views/ChangeCollectionView.axaml.cs

@@ -166,6 +166,49 @@ public event EventHandler<RoutedEventArgs> ChangeDoubleTapped
         public ChangeCollectionView()
         {
             InitializeComponent();
+            AddHandler(PointerReleasedEvent, OnChangePointerReleased, RoutingStrategies.Bubble, true);
+            AddHandler(KeyDownEvent, OnChangeKeyDown, RoutingStrategies.Bubble, true);
+        }
+
+        public static readonly RoutedEvent<RoutedEventArgs> ChangeActivatedEvent =
+            RoutedEvent.Register<ChangeCollectionView, RoutedEventArgs>(nameof(ChangeActivated), RoutingStrategies.Bubble);
+
+        public event EventHandler<RoutedEventArgs> ChangeActivated
+        {
+            add { AddHandler(ChangeActivatedEvent, value); }
+            remove { RemoveHandler(ChangeActivatedEvent, value); }
+        }
+
+        private void OnChangePointerReleased(object sender, PointerReleasedEventArgs e)
+        {
+            if (e.InitialPressMouseButton != MouseButton.Left || e.KeyModifiers != KeyModifiers.None ||
+                Selection is not { Count: 1, HasFolder: false })
+                return;
+
+            for (var source = e.Source as Control; source != null && source != this; source = source.GetVisualParent() as Control)
+            {
+                if (source is not ListBoxItem item)
+                    continue;
+
+                var change = item.DataContext switch
+                {
+                    Models.Change c => c,
+                    ViewModels.ChangeTreeNode { IsFolder: false } node => node.Change,
+                    _ => null,
+                };
+                if (change == Selection.Changes[0])
+                    RaiseEvent(new RoutedEventArgs(ChangeActivatedEvent));
+                return;
+            }
+        }
+
+        private void OnChangeKeyDown(object sender, KeyEventArgs e)
+        {
+            if (e.KeyModifiers != KeyModifiers.None || Selection is not { Count: 1, HasFolder: false })
+                return;
+
+            if (e.Key is Key.Enter or Key.Space or Key.Up or Key.Down or Key.Home or Key.End or Key.PageUp or Key.PageDown)
+                RaiseEvent(new RoutedEventArgs(ChangeActivatedEvent));
         }
 
         public void ToggleNodeIsExpanded(ViewModels.ChangeTreeNode node)

src/Views/ChangeListLayout.cs

@@ -0,0 +1,59 @@
+using Avalonia;
+using Avalonia.Controls;
+
+namespace SourceGit.Views
+{
+    public class ChangeListLayout : Grid
+    {
+        public static readonly StyledProperty<bool> IsFileListOnlyProperty =
+            AvaloniaProperty.Register<ChangeListLayout, bool>(nameof(IsFileListOnly));
+
+        public static readonly StyledProperty<GridLength> ListWidthProperty =
+            AvaloniaProperty.Register<ChangeListLayout, GridLength>(nameof(ListWidth), new GridLength(256));
+
+        public bool IsFileListOnly
+        {
+            get => GetValue(IsFileListOnlyProperty);
+            set => SetValue(IsFileListOnlyProperty, value);
+        }
+
+        public GridLength ListWidth
+        {
+            get => GetValue(ListWidthProperty);
+            set => SetValue(ListWidthProperty, value);
+        }
+
+        protected override System.Type StyleKeyOverride => typeof(Grid);
+
+        public ChangeListLayout()
+        {
+            ColumnDefinitions = new ColumnDefinitions("256,4,*");
+            ColumnDefinitions[0].PropertyChanged += (_, e) =>
+            {
+                if (!_updating && !IsFileListOnly && e.Property == ColumnDefinition.WidthProperty)
+                    SetCurrentValue(ListWidthProperty, ColumnDefinitions[0].Width);
+            };
+            RefreshLayout();
+        }
+
+        protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs change)
+        {
+            base.OnPropertyChanged(change);
+            if (change.Property == IsFileListOnlyProperty || change.Property == ListWidthProperty)
+                RefreshLayout();
+        }
+
+        private void RefreshLayout()
+        {
+            _updating = true;
+            ColumnDefinitions[0].MinWidth = IsFileListOnly ? 0 : 200;
+            ColumnDefinitions[0].Width = IsFileListOnly ? GridLength.Star : ListWidth;
+            ColumnDefinitions[1].Width = new GridLength(IsFileListOnly ? 0 : 4);
+            ColumnDefinitions[2].MinWidth = IsFileListOnly ? 0 : 100;
+            ColumnDefinitions[2].Width = IsFileListOnly ? new GridLength(0) : GridLength.Star;
+            _updating = false;
+        }
+
+        private bool _updating = false;
+    }
+}