LibGfx: Rely on fontconfig(if enabled) for font directory resolution

this commit also introduces GlobalFontConfig class that is now
responsible for fontconfig initialization. it seems sane, even thought
FcInit's docs state that if the default configuration has already been
loaded, this routine does nothing.

Libraries/LibGfx/CMakeLists.txt

@@ -72,6 +72,10 @@ if (HAS_VULKAN)
     list(APPEND SOURCES VulkanContext.cpp)
 endif()
 
+if (HAS_FONTCONFIG)
+    list(APPEND SOURCES Font/GlobalFontConfig.cpp)
+endif()
+
 serenity_lib(LibGfx gfx)
 
 target_link_libraries(LibGfx PRIVATE LibCompress LibCore LibCrypto LibFileSystem LibRIFF LibTextCodec LibIPC LibUnicode LibURL)

Libraries/LibGfx/Font/FontDatabase.cpp

@@ -13,6 +13,10 @@
 #    include <FindDirectory.h>
 #endif
 
+#ifdef USE_FONTCONFIG
+#    include <LibGfx/Font/GlobalFontConfig.h>
+#endif
+
 namespace Gfx {
 
 // Key function for SystemFontProvider to emit the vtable here
@@ -51,7 +55,16 @@ void FontDatabase::for_each_typeface_with_family_name(FlyString const& family_na
 
 ErrorOr<Vector<String>> FontDatabase::font_directories()
 {
-#if defined(AK_OS_HAIKU)
+#if defined(USE_FONTCONFIG)
+    Vector<String> paths;
+    FcConfig* config = Gfx::GlobalFontConfig::the().get();
+    FcStrList* dirs = FcConfigGetFontDirs(config);
+    while (FcChar8* dir = FcStrListNext(dirs)) {
+        char const* dir_cstring = reinterpret_cast<char const*>(dir);
+        paths.append(TRY(String::from_utf8(StringView { dir_cstring, strlen(dir_cstring) })));
+    }
+    return paths;
+#elif defined(AK_OS_HAIKU)
     Vector<String> paths_vector;
     char** paths;
     size_t paths_count;

Libraries/LibGfx/Font/GlobalFontConfig.cpp

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2025, blukai <init1@protonmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/Assertions.h>
+#include <LibGfx/Font/GlobalFontConfig.h>
+#include <fontconfig/fontconfig.h>
+
+namespace Gfx {
+
+GlobalFontConfig::GlobalFontConfig()
+{
+    FcBool inited = FcInit();
+    VERIFY(inited);
+
+    m_config = FcConfigGetCurrent();
+    FcConfigReference(m_config);
+}
+
+GlobalFontConfig::~GlobalFontConfig()
+{
+    FcConfigDestroy(m_config);
+}
+
+GlobalFontConfig& GlobalFontConfig::the()
+{
+    static GlobalFontConfig s_the;
+    return s_the;
+}
+
+FcConfig* GlobalFontConfig::get()
+{
+    return m_config;
+}
+
+}

Libraries/LibGfx/Font/GlobalFontConfig.h

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2025, blukai <init1@protonmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <fontconfig/fontconfig.h>
+
+namespace Gfx {
+
+class GlobalFontConfig {
+public:
+    static GlobalFontConfig& the();
+    FcConfig* get();
+
+private:
+    GlobalFontConfig();
+    ~GlobalFontConfig();
+
+    GlobalFontConfig(GlobalFontConfig const&) = delete;
+    GlobalFontConfig& operator=(GlobalFontConfig const&) = delete;
+
+    FcConfig* m_config;
+};
+
+}

Libraries/LibWebView/Plugins/FontPlugin.cpp

@@ -16,7 +16,7 @@
 #include <LibWebView/Plugins/FontPlugin.h>
 
 #ifdef USE_FONTCONFIG
-#    include <fontconfig/fontconfig.h>
+#    include <LibGfx/Font/GlobalFontConfig.h>
 #endif
 
 namespace WebView {
@@ -24,13 +24,6 @@ namespace WebView {
 FontPlugin::FontPlugin(bool is_layout_test_mode, Gfx::SystemFontProvider* font_provider)
     : m_is_layout_test_mode(is_layout_test_mode)
 {
-#ifdef USE_FONTCONFIG
-    {
-        auto fontconfig_initialized = FcInit();
-        VERIFY(fontconfig_initialized);
-    }
-#endif
-
     if (!font_provider)
         font_provider = &static_cast<Gfx::PathFontProvider&>(Gfx::FontDatabase::the().install_system_font_provider(make<Gfx::PathFontProvider>()));
     if (is<Gfx::PathFontProvider>(*font_provider)) {
@@ -114,7 +107,7 @@ static Optional<String> query_fontconfig_for_generic_family(Web::Platform::Gener
         VERIFY_NOT_REACHED();
     }
 
-    auto* config = FcConfigGetCurrent();
+    auto* config = Gfx::GlobalFontConfig::the().get();
     VERIFY(config);
 
     FcPattern* pattern = FcNameParse(reinterpret_cast<FcChar8 const*>(pattern_string));