Add Mermaid support and .mmd detection #1893

2026-05-08 03:06:29 +08:00 · 2026-03-27 10:45:20 +08:00
parent 20df0b2889
commit ae67d5247c
4 changed files with 81 additions and 8 deletions
@@ -78,6 +78,7 @@ public class MarkdownPanel : WebpagePanel
        var bytes = File.ReadAllBytes(path);
        var encoding = CharsetDetector.DetectFromBytes(bytes).Detected?.Encoding ?? Encoding.Default;
        var content = encoding.GetString(bytes);
+        content = PrepareMarkdownContent(path, content);

        var template = ReadString("/md2html.html");
        
@@ -99,6 +100,75 @@ public class MarkdownPanel : WebpagePanel
        return html;
    }

+    private static string PrepareMarkdownContent(string path, string content)
+    {
+        var extension = Path.GetExtension(path);
+
+        if (extension.Equals(".mermaid", StringComparison.OrdinalIgnoreCase))
+            return WrapAsMermaidCodeFence(content);
+
+        if (extension.Equals(".mmd", StringComparison.OrdinalIgnoreCase)
+            && IsLikelyMermaidDocument(content))
+            return WrapAsMermaidCodeFence(content);
+
+        return content;
+    }
+
+    private static string WrapAsMermaidCodeFence(string content)
+    {
+        var normalized = content.Replace("\r\n", "\n").Trim('\n');
+        return $"```mermaid\n{normalized}\n```";
+    }
+
+    private static bool IsLikelyMermaidDocument(string content)
+    {
+        if (string.IsNullOrWhiteSpace(content))
+            return false;
+
+        if (content.IndexOf("```mermaid", StringComparison.OrdinalIgnoreCase) >= 0)
+            return false;
+
+        using var reader = new StringReader(content);
+        string line;
+        while ((line = reader.ReadLine()) != null)
+        {
+            var trimmed = line.Trim();
+            if (trimmed.Length == 0 || trimmed.StartsWith("%%", StringComparison.Ordinal))
+                continue;
+
+            return trimmed.StartsWith("graph ", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.Equals("graph", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("flowchart ", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.Equals("flowchart", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("sequenceDiagram", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("classDiagram", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("stateDiagram", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("stateDiagram-v2", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("erDiagram", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("journey", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("gantt", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("pie", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("mindmap", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("timeline", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("gitGraph", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("quadrantChart", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("requirementDiagram", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("c4Context", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("c4Container", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("c4Component", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("c4Dynamic", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("c4Deployment", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("xychart-beta", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("block-beta", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("packet-beta", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("architecture-beta", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("kanban", StringComparison.OrdinalIgnoreCase)
+                   || trimmed.StartsWith("sankey-beta", StringComparison.OrdinalIgnoreCase);
+        }
+
+        return false;
+    }
+
    protected override void WebView_WebResourceRequested(object sender, CoreWebView2WebResourceRequestedEventArgs args)
    {
        Debug.WriteLine($"[{args.Request.Method}] {args.Request.Uri}");