Update AppBuilderExtension.cs

v2rayN/v2rayN.Desktop/Common/AppBuilderExtension.cs

@@ -1,14 +1,83 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.IO;
+using Avalonia.Media;
+
 namespace v2rayN.Desktop.Common;
 
 public static class AppBuilderExtension
 {
     public static AppBuilder WithFontByDefault(this AppBuilder appBuilder)
     {
-        var uri = Path.Combine(Global.AvaAssets, "Fonts#Noto Sans SC");
-        return appBuilder.With(new FontManagerOptions()
+        if (!OperatingSystem.IsLinux())
         {
-            //DefaultFamilyName = uri,
-            FontFallbacks = new[] { new FontFallback { FontFamily = new FontFamily(uri) } }
+            var uri = Path.Combine(Global.AvaAssets, "Fonts#Noto Sans SC");
+            return appBuilder.With(new FontManagerOptions
+            {
+                FontFallbacks = new[]
+                {
+                    new FontFallback { FontFamily = new FontFamily(uri) }
+                }
+            });
+        }
+
+        var fallbacks = new List<FontFallback>();
+
+        string? zhFont = RunFcMatch("sans:lang=zh-cn");
+
+        if (!string.IsNullOrWhiteSpace(zhFont))
+        {
+            fallbacks.Add(new FontFallback
+            {
+                FontFamily = new FontFamily(zhFont)
+            });
+        }
+
+        string? emojiFont = RunFcMatch("emoji");
+
+        if (!string.IsNullOrWhiteSpace(emojiFont))
+        {
+            fallbacks.Add(new FontFallback
+            {
+                FontFamily = new FontFamily(emojiFont)
+            });
+        }
+
+        var notoUri = Path.Combine(Global.AvaAssets, "Fonts#Noto Sans SC");
+        fallbacks.Add(new FontFallback
+        {
+            FontFamily = new FontFamily(notoUri)
+        });
+
+        return appBuilder.With(new FontManagerOptions
+        {
+            FontFallbacks = fallbacks.ToArray()
         });
     }
+
+    private static string? RunFcMatch(string pattern)
+    {
+        try
+        {
+            var psi = new ProcessStartInfo
+            {
+                FileName = "/bin/bash",
+                ArgumentList = { "-c", $"fc-match -f \"%{{file}}\\n\" \"{pattern}\" | head -n 1" },
+                RedirectStandardOutput = true,
+                RedirectStandardError = true,
+                UseShellExecute = false
+            };
+
+            using var p = Process.Start(psi);
+            if (p == null) return null;
+
+            string output = p.StandardOutput.ReadToEnd().Trim();
+            return string.IsNullOrWhiteSpace(output) ? null : output;
+        }
+        catch
+        {
+            return null;
+        }
+    }
 }