feat(raylib): support system monospace font via fontconfig

src/raylib_editor.cpp

@@ -15,6 +15,9 @@
 #include <string>
 #include <vector>
 #include <fmt/core.h>
+#include <cstdio>
+#include <memory>
+#include <array>
 
 namespace lumacs {
 
@@ -28,6 +31,29 @@ static ::Color ToRLColor(const lumacs::Color& c) {
     return RL_Color((unsigned char)c.r, (unsigned char)c.g, (unsigned char)c.b);
 }
 
+// Helper to get system monospace font path via fontconfig
+static std::string get_system_monospace_font_path() {
+    std::string result;
+    std::array<char, 128> buffer;
+    std::unique_ptr<FILE, decltype(&pclose)> pipe(popen("fc-match monospace --format=\"%{file}\"", "r"), pclose);
+    
+    if (!pipe) {
+        spdlog::warn("Failed to run fc-match to find system monospace font");
+        return "";
+    }
+    
+    while (fgets(buffer.data(), buffer.size(), pipe.get()) != nullptr) {
+        result += buffer.data();
+    }
+    
+    // Trim newline if present
+    if (!result.empty() && result.back() == '\n') {
+        result.pop_back();
+    }
+    
+    return result;
+}
+
 RaylibEditor::RaylibEditor() {
 }
 
@@ -47,15 +73,23 @@ void RaylibEditor::init() {
     line_height_ = 20;
     char_width_ = 10;
     
-    const char* font_paths[] = {
-        "/usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf",
-        "/usr/share/fonts/TTF/DejaVuSansMono.ttf",
-        "resources/font.ttf"
-    };
+    // Dynamic font path list
+    std::vector<std::string> font_paths;
+    
+    // 1. Try system monospace font via fontconfig
+    std::string system_font = get_system_monospace_font_path();
+    if (!system_font.empty()) {
+        font_paths.push_back(system_font);
+    }
+    
+    // 2. Fallback hardcoded paths
+    font_paths.push_back("/usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf");
+    font_paths.push_back("/usr/share/fonts/TTF/DejaVuSansMono.ttf");
+    font_paths.push_back("resources/font.ttf");
     
-    for (const char* path : font_paths) {
-        if (FileExists(path)) {
-            Font loaded = LoadFontEx(path, font_size_, 0, 0);
+    for (const auto& path : font_paths) {
+        if (FileExists(path.c_str())) {
+            Font loaded = LoadFontEx(path.c_str(), font_size_, 0, 0);
             if (loaded.texture.id != 0) {
                 font_ = loaded;
                 SetTextureFilter(font_.texture, TEXTURE_FILTER_BILINEAR);
@@ -223,7 +257,7 @@ void RaylibEditor::render() {
 }
 
 void RaylibEditor::draw_layout(LayoutNode* node, Rectangle area) {
-    if (!node) return;
+    if (!node) return; 
     
     if (node->type == LayoutNode::Type::Leaf) {
         if (node->window) {
@@ -342,4 +376,4 @@ std::unique_ptr<IEditorView> create_raylib_editor() {
     return std::make_unique<RaylibEditor>();
 }
 
-} // namespace lumacs
+} // namespace lumacs