add: 过滤等宽字体。bug：切屏导致选中字体失效

Author: chenxuuu

llcomNext/LLCOM/ViewModels/Pages/SettingPageViewModel.cs

@@ -29,22 +29,24 @@ public SettingPageViewModel(Func<Type, ViewModelBase> getService)
             //用skia接口获取系统字体列表
             var fontMgr = SkiaSharp.SKFontManager.Default;
             var fonts = new List<string>();
+            var monoFonts = new List<string>();
             foreach (var f in fontMgr.FontFamilies)
             {
                 fonts.Add(f);
+                using var typeface = fontMgr.MatchFamily(f) ;
+                if (typeface.IsFixedPitch)
+                    monoFonts.Add(f);
             }
             //把列表内容按字母排序
             fonts.Sort();
+            monoFonts.Sort();
             //添加到系统字体列表
             foreach (var f in fonts)
-            {
                 SystemFontList.Add(f);
-            }
+            foreach (var f in monoFonts)
+                MonoFontList.Add(f);
             //找找看当前设置的是什么字体，对应上
-            PacketFontIndex = SystemFontList.IndexOf(Services.Utils.Setting.PacketFont);
-            PacketHexFontIndex = SystemFontList.IndexOf(Services.Utils.Setting.PacketHexFont);
-            PacketHeaderFontIndex = SystemFontList.IndexOf(Services.Utils.Setting.PacketHeaderFont);
-            PacketExtraFontIndex = SystemFontList.IndexOf(Services.Utils.Setting.PacketExtraFont);
+            RefreshFontIndexCommand.Execute(null);
 
             //是否已经检查过更新？
             if (Services.Utils.HasUpdate())
@@ -82,7 +84,9 @@ public SettingPageViewModel(Func<Type, ViewModelBase> getService)
     #region FontSettings
 
     [ObservableProperty]
-    private ObservableCollection<FontFamily> _SystemFontList = new();
+    private ObservableCollection<FontFamily> _systemFontList = new();
+    [ObservableProperty]
+    private ObservableCollection<FontFamily> _monoFontList = new();
     [ObservableProperty]
     private int _packetFontIndex;
     [ObservableProperty]
@@ -91,7 +95,20 @@ public SettingPageViewModel(Func<Type, ViewModelBase> getService)
     private int _packetHeaderFontIndex;
     [ObservableProperty]
     private int _packetExtraFontIndex;
+    [ObservableProperty]
+    private bool _useMonoFont;
 
+    [RelayCommand]
+    private void RefreshFontIndex()
+    {
+        var list = UseMonoFont ? MonoFontList : SystemFontList;
+        //刷新字体索引
+        PacketFontIndex = list.IndexOf(Services.Utils.Setting.PacketFont);
+        PacketHexFontIndex = list.IndexOf(Services.Utils.Setting.PacketHexFont);
+        PacketHeaderFontIndex = list.IndexOf(Services.Utils.Setting.PacketHeaderFont);
+        PacketExtraFontIndex = list.IndexOf(Services.Utils.Setting.PacketExtraFont);
+    }
+    
     #endregion
 
     #region About

llcomNext/LLCOM/Views/Pages/SettingPageView.axaml

@@ -14,6 +14,14 @@
     <Design.DataContext>
         <vm:SettingPageViewModel />
     </Design.DataContext>
+    <UserControl.Styles>
+        <Style Selector="ComboBox.ListFontAll">
+            <Setter Property="ItemsSource" Value="{Binding SystemFontList}" />
+        </Style>
+        <Style Selector="ComboBox.ListFontMono">
+            <Setter Property="ItemsSource" Value="{Binding MonoFontList}" />
+        </Style>
+    </UserControl.Styles>
     <TabControl>
         <TabItem Header="常规设置">
             <ScrollViewer Background="{DynamicResource SemiGrey0}">
@@ -25,6 +33,12 @@
         <TabItem Header="外观与字体" IsSelected="True">
             <ScrollViewer Background="{DynamicResource SemiGrey0}">
                 <StackPanel Margin="10" Spacing="5">
+                    <CheckBox
+                        Margin="5,5,5,0"
+                        Command="{Binding RefreshFontIndexCommand}"
+                        Content="限制使用等宽字体"
+                        IsChecked="{Binding UseMonoFont}" />
+                    <Separator Margin="0,10" />
                     <Grid
                         Margin="5,0"
                         ColumnDefinitions="*, 250"
@@ -38,7 +52,8 @@
                             Grid.Row="0"
                             Grid.Column="1"
                             Width="250"
-                            ItemsSource="{Binding SystemFontList}"
+                            Classes.ListFontAll="{Binding !UseMonoFont}"
+                            Classes.ListFontMono="{Binding UseMonoFont}"
                             SelectedIndex="{Binding PacketFontIndex}"
                             SelectedItem="{Binding PacketFontFamily, Source={x:Static services:Utils.Setting}}">
                             <ComboBox.ItemTemplate>
@@ -56,7 +71,8 @@
                             Grid.Row="2"
                             Grid.Column="1"
                             Width="250"
-                            ItemsSource="{Binding SystemFontList}"
+                            Classes.ListFontAll="{Binding !UseMonoFont}"
+                            Classes.ListFontMono="{Binding UseMonoFont}"
                             SelectedIndex="{Binding PacketHexFontIndex}"
                             SelectedItem="{Binding PacketHexFontFamily, Source={x:Static services:Utils.Setting}}">
                             <ComboBox.ItemTemplate>
@@ -74,7 +90,8 @@
                             Grid.Row="4"
                             Grid.Column="1"
                             Width="250"
-                            ItemsSource="{Binding SystemFontList}"
+                            Classes.ListFontAll="{Binding !UseMonoFont}"
+                            Classes.ListFontMono="{Binding UseMonoFont}"
                             SelectedIndex="{Binding PacketHeaderFontIndex}"
                             SelectedItem="{Binding PacketHeaderFontFamily, Source={x:Static services:Utils.Setting}}">
                             <ComboBox.ItemTemplate>
@@ -92,7 +109,8 @@
                             Grid.Row="6"
                             Grid.Column="1"
                             Width="250"
-                            ItemsSource="{Binding SystemFontList}"
+                            Classes.ListFontAll="{Binding !UseMonoFont}"
+                            Classes.ListFontMono="{Binding UseMonoFont}"
                             SelectedIndex="{Binding PacketExtraFontIndex}"
                             SelectedItem="{Binding PacketExtraFontFamily, Source={x:Static services:Utils.Setting}}">
                             <ComboBox.ItemTemplate>