feature: supports to disable GitHub style default avatar (#1814)

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

Author: love-linger

src/Resources/Locales/en_US.axaml

@@ -575,6 +575,7 @@
   <x:String x:Key="Text.Preferences.General.ShowChildren" xml:space="preserve">Show children in the commit details</x:String>
   <x:String x:Key="Text.Preferences.General.ShowTagsInGraph" xml:space="preserve">Show tags in commit graph</x:String>
   <x:String x:Key="Text.Preferences.General.SubjectGuideLength" xml:space="preserve">Subject Guide Length</x:String>
+  <x:String x:Key="Text.Preferences.General.UseGitHubStyleAvatar" xml:space="preserve">Generate Github style default avatar</x:String>
   <x:String x:Key="Text.Preferences.Git" xml:space="preserve">GIT</x:String>
   <x:String x:Key="Text.Preferences.Git.CRLF" xml:space="preserve">Enable Auto CRLF</x:String>
   <x:String x:Key="Text.Preferences.Git.DefaultCloneDir" xml:space="preserve">Default Clone Dir</x:String>

src/Resources/Locales/zh_CN.axaml

@@ -579,6 +579,7 @@
   <x:String x:Key="Text.Preferences.General.ShowChildren" xml:space="preserve">在提交详情页中显示子提交列表</x:String>
   <x:String x:Key="Text.Preferences.General.ShowTagsInGraph" xml:space="preserve">在提交路线图中显示标签</x:String>
   <x:String x:Key="Text.Preferences.General.SubjectGuideLength" xml:space="preserve">SUBJECT字数检测</x:String>
+  <x:String x:Key="Text.Preferences.General.UseGitHubStyleAvatar" xml:space="preserve">生成GitHub风格的默认头像</x:String>
   <x:String x:Key="Text.Preferences.Git" xml:space="preserve">GIT配置</x:String>
   <x:String x:Key="Text.Preferences.Git.CRLF" xml:space="preserve">自动换行转换</x:String>
   <x:String x:Key="Text.Preferences.Git.DefaultCloneDir" xml:space="preserve">默认克隆路径</x:String>

src/Resources/Locales/zh_TW.axaml

@@ -579,6 +579,7 @@
   <x:String x:Key="Text.Preferences.General.ShowChildren" xml:space="preserve">在提交詳細資訊中顯示後續提交</x:String>
   <x:String x:Key="Text.Preferences.General.ShowTagsInGraph" xml:space="preserve">在路線圖中顯示標籤</x:String>
   <x:String x:Key="Text.Preferences.General.SubjectGuideLength" xml:space="preserve">提交標題字數偵測</x:String>
+  <x:String x:Key="Text.Preferences.General.UseGitHubStyleAvatar" xml:space="preserve">生成 GitHub 風格的預設頭像</x:String>
   <x:String x:Key="Text.Preferences.Git" xml:space="preserve">Git 設定</x:String>
   <x:String x:Key="Text.Preferences.Git.CRLF" xml:space="preserve">自動換行轉換</x:String>
   <x:String x:Key="Text.Preferences.Git.DefaultCloneDir" xml:space="preserve">預設複製 (clone) 路徑</x:String>

src/ViewModels/Preferences.cs

@@ -170,6 +170,12 @@ public bool UseAutoHideScrollBars
             set => SetProperty(ref _useAutoHideScrollBars, value);
         }
 
+        public bool UseGitHubStyleAvatar
+        {
+            get => _useGitHubStyleAvatar;
+            set => SetProperty(ref _useGitHubStyleAvatar, value);
+        }
+
         public bool Check4UpdatesOnStartup
         {
             get => _check4UpdatesOnStartup;
@@ -725,6 +731,7 @@ private bool RemoveInvalidRepositoriesRecursive(List<RepositoryNode> collection)
         private int _subjectGuideLength = 50;
         private bool _useFixedTabWidth = true;
         private bool _useAutoHideScrollBars = true;
+        private bool _useGitHubStyleAvatar = true;
         private bool _showAuthorTimeInGraph = false;
         private bool _showChildren = false;
 

src/Views/Avatar.cs

@@ -1,11 +1,13 @@
 using System;
+using System.Collections.Generic;
 using System.Globalization;
 using System.IO;
 using System.Security.Cryptography;
 using System.Text;
 
 using Avalonia;
 using Avalonia.Controls;
+using Avalonia.Data;
 using Avalonia.Interactivity;
 using Avalonia.Media;
 using Avalonia.Media.Imaging;
@@ -24,9 +26,25 @@ public Models.User User
             set => SetValue(UserProperty, value);
         }
 
+        public static readonly StyledProperty<bool> UseGitHubStyleAvatarProperty =
+            AvaloniaProperty.Register<Avatar, bool>(nameof(UseGitHubStyleAvatar));
+
+        public bool UseGitHubStyleAvatar
+        {
+            get => GetValue(UseGitHubStyleAvatarProperty);
+            set => SetValue(UseGitHubStyleAvatarProperty, value);
+        }
+
         public Avatar()
         {
             RenderOptions.SetBitmapInterpolationMode(this, BitmapInterpolationMode.HighQuality);
+
+            this.Bind(UseGitHubStyleAvatarProperty, new Binding()
+            {
+                Mode = BindingMode.OneWay,
+                Source = ViewModels.Preferences.Instance,
+                Path = "UseGitHubStyleAvatar"
+            });
         }
 
         public override void Render(DrawingContext context)
@@ -42,6 +60,34 @@ public override void Render(DrawingContext context)
             {
                 context.DrawImage(_img, rect);
             }
+            else if (!UseGitHubStyleAvatar)
+            {
+                var fallback = GetFallbackString(User.Name);
+                var typeface = new Typeface("fonts:SourceGit#JetBrains Mono");
+                var label = new FormattedText(
+                    fallback,
+                    CultureInfo.CurrentCulture,
+                    FlowDirection.LeftToRight,
+                    typeface,
+                    Bounds.Width * 0.65,
+                    Brushes.White);
+
+                var chars = fallback.ToCharArray();
+                var sum = 0;
+                foreach (var c in chars)
+                    sum += Math.Abs(c);
+
+                var bg = new LinearGradientBrush()
+                {
+                    GradientStops = FALLBACK_GRADIENTS[sum % FALLBACK_GRADIENTS.Length],
+                    StartPoint = new RelativePoint(0, 0, RelativeUnit.Relative),
+                    EndPoint = new RelativePoint(0, 1, RelativeUnit.Relative),
+                };
+
+                Point textOrigin = new Point((Bounds.Width - label.Width) * 0.5, (Bounds.Height - label.Height) * 0.5);
+                context.DrawRectangle(bg, null, new Rect(0, 0, Bounds.Width, Bounds.Height), corner, corner);
+                context.DrawText(label, textOrigin);
+            }
             else
             {
                 context.DrawRectangle(Brushes.White, new Pen(new SolidColorBrush(Colors.Black, 0.3f), 0.65f), rect, corner, corner);
@@ -130,6 +176,11 @@ protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs chang
                 _img = Models.AvatarManager.Instance.Request(User.Email, false);
                 InvalidateVisual();
             }
+            else if (change.Property == UseGitHubStyleAvatarProperty)
+            {
+                if (_img == null)
+                    InvalidateVisual();
+            }
         }
 
         private void OnContextRequested(object sender, ContextRequestedEventArgs e)
@@ -220,6 +271,30 @@ private void OnContextRequested(object sender, ContextRequestedEventArgs e)
             menu.Open(this);
         }
 
+        private string GetFallbackString(string name)
+        {
+            if (string.IsNullOrWhiteSpace(name))
+                return "?";
+
+            var parts = name.Split(' ', StringSplitOptions.RemoveEmptyEntries);
+            var chars = new List<char>();
+            foreach (var part in parts)
+                chars.Add(part[0]);
+
+            if (chars.Count >= 2 && char.IsAsciiLetterOrDigit(chars[0]) && char.IsAsciiLetterOrDigit(chars[^1]))
+                return string.Format("{0}{1}", chars[0], chars[^1]);
+
+            return name.Substring(0, 1);
+        }
+
+        private static readonly GradientStops[] FALLBACK_GRADIENTS = [
+            new GradientStops() { new GradientStop(Colors.Orange, 0), new GradientStop(Color.FromRgb(255, 213, 134), 1) },
+            new GradientStops() { new GradientStop(Colors.DodgerBlue, 0), new GradientStop(Colors.LightSkyBlue, 1) },
+            new GradientStops() { new GradientStop(Colors.LimeGreen, 0), new GradientStop(Color.FromRgb(124, 241, 124), 1) },
+            new GradientStops() { new GradientStop(Colors.Orchid, 0), new GradientStop(Color.FromRgb(248, 161, 245), 1) },
+            new GradientStops() { new GradientStop(Colors.Tomato, 0), new GradientStop(Color.FromRgb(252, 165, 150), 1) },
+        ];
+
         private Bitmap _img = null;
     }
 }

src/Views/Preferences.axaml

@@ -46,7 +46,7 @@
           <TabItem.Header>
             <TextBlock Classes="tab_header" Text="{DynamicResource Text.Preferences.General}"/>
           </TabItem.Header>
-          <Grid Margin="8" RowDefinitions="32,32,32,32,32,32,32,32,32,32,32,Auto" ColumnDefinitions="Auto,*">
+          <Grid Margin="8" RowDefinitions="32,32,32,32,32,32,32,32,32,32,32,32,Auto" ColumnDefinitions="Auto,*">
             <TextBlock Grid.Row="0" Grid.Column="0"
                        Text="{DynamicResource Text.Preferences.General.Locale}"
                        HorizontalAlignment="Right"
@@ -163,6 +163,11 @@
                       IsChecked="{Binding EnableCompactFoldersInChangesTree, Mode=TwoWay}"/>
 
             <CheckBox Grid.Row="11" Grid.Column="1"
+                      Height="32"
+                      Content="{DynamicResource Text.Preferences.General.UseGitHubStyleAvatar}"
+                      IsChecked="{Binding UseGitHubStyleAvatar, Mode=TwoWay}"/>
+
+            <CheckBox Grid.Row="12" Grid.Column="1"
                       Height="32"
                       Content="{DynamicResource Text.Preferences.General.Check4UpdatesOnStartup}"
                       IsVisible="{x:Static s:App.IsCheckForUpdateCommandVisible}"