feat: Enumerate fonts on Linux using Fontconfig when available (#1821)

### Problem description

The fonts list on Linux does not show all system fonts, and does not
show font names at all.

### Implementation description

Use Fontconfig to make the list less bad if Fontconfig headers are
available.

### Additional things

I like fonts.

---------

Co-authored-by: Nik <werwolv98@gmail.com>

dist/AppImageBuilder.yml

@@ -30,6 +30,7 @@ AppDir:
     - libbz2-1.0:amd64
     - libcap2:amd64
     - libdbus-1-3:amd64
+    - libfontconfig1:amd64
     - libgpg-error0:amd64
     - liblzma5:amd64
     - libnss-mdns:amd64

dist/Arch/Dockerfile

@@ -13,6 +13,7 @@ RUN pacman -S --needed --noconfirm      \
     glfw-x11                            \
     file                                \
     mbedtls                             \
+    fontconfig                          \
     freetype2                           \
     curl                                \
     dbus                                \

dist/Arch/PKGBUILD

@@ -8,7 +8,7 @@ pkgdesc="A Hex Editor for Reverse Engineers, Programmers and people who value th
 arch=("x86_64")
 url="https://github.com/WerWolv/ImHex"
 license=('GPL2')
-depends=(glfw mbedtls freetype2 libglvnd dbus gtk3 curl fmt yara nlohmann-json zlib bzip2 xz zstd)
+depends=(glfw mbedtls fontconfig freetype2 libglvnd dbus gtk3 curl fmt yara nlohmann-json zlib bzip2 xz zstd)
 makedepends=(git)
 provides=(imhex)
 conflicts=(imhex)

dist/DEBIAN/control.in

@@ -4,7 +4,7 @@ Section: editors
 Priority: optional
 Architecture: amd64
 License: GNU GPL-2
-Depends: libglfw3 | libglfw3-wayland, libmagic1, libmbedtls14, libfreetype6, libopengl0, libdbus-1-3, xdg-desktop-portal
+Depends: libfontconfig1, libglfw3 | libglfw3-wayland, libmagic1, libmbedtls14, libfreetype6, libopengl0, libdbus-1-3, xdg-desktop-portal
 Maintainer: WerWolv <hey@werwolv.net>
 Description: ImHex Hex Editor
  A Hex Editor for Reverse Engineers, Programmers and

dist/get_deps_archlinux.sh

@@ -5,6 +5,7 @@ pacman -S $@ --needed \
   gcc           \
   lld           \
   glfw          \
+  fontconfig    \
   file          \
   mbedtls       \
   freetype2     \

dist/get_deps_debian.sh

@@ -18,6 +18,7 @@ apt install -y \
   libglm-dev            \
   libmagic-dev          \
   libmbedtls-dev        \
+  libfontconfig-dev     \
   libfreetype-dev       \
   libdbus-1-dev         \
   libcurl4-gnutls-dev   \

dist/get_deps_fedora.sh

@@ -4,6 +4,7 @@ dnf install -y      \
   cmake             \
   dbus-devel        \
   file-devel        \
+  fontconfig-devel  \
   freetype-devel    \
   libcurl-devel     \
   gcc-c++           \

dist/get_deps_tumbleweed.sh

@@ -5,6 +5,7 @@ zypper install     \
   ninja            \
   gcc12            \
   gcc12-c++        \
+  fontconfig-devel \
   freetype2-devel  \
   libcurl-devel    \
   dbus-1-devel     \

dist/rpm/imhex.spec

@@ -16,6 +16,7 @@ BuildRequires:  cmake
 BuildRequires:  desktop-file-utils
 BuildRequires:  dbus-devel
 BuildRequires:  file-devel
+BuildRequires:  fontconfig-devel
 BuildRequires:  freetype-devel
 BuildRequires:  fmt-devel
 BuildRequires:  gcc-c++

main/gui/CMakeLists.txt

@@ -63,6 +63,15 @@ if (WIN32)
     target_link_libraries(main PRIVATE usp10 wsock32 ws2_32 Dwmapi.lib Winmm.lib)
 else ()
     target_link_libraries(main PRIVATE pthread)
+
+    if (NOT APPLE)
+        find_package(Fontconfig)
+        if (TARGET Fontconfig::Fontconfig)
+            message(STATUS "Using Fontconfig version: ${Fontconfig_VERSION}")
+            target_link_libraries(main PRIVATE Fontconfig::Fontconfig)
+            target_compile_definitions(main PRIVATE IMHEX_HAS_FONTCONFIG)
+        endif ()
+    endif ()
 endif ()
 
 precompileHeaders(main ${CMAKE_CURRENT_SOURCE_DIR}/include)

main/gui/source/window/linux_window.cpp

@@ -22,6 +22,10 @@
     #include <string.h>
     #include <ranges>
 
+    #if defined(IMHEX_HAS_FONTCONFIG)
+        #include <fontconfig/fontconfig.h>
+    #endif
+
 namespace hex {
 
     bool isFileInPath(const std::fs::path &filename) {
@@ -48,7 +52,43 @@ namespace hex {
         } // Hopefully one of these commands is installed
     }
 
+    #if defined(IMHEX_HAS_FONTCONFIG)
+        static bool enumerateFontConfig() {
+            if (!FcInit())
+                return false;
+
+            ON_SCOPE_EXIT { FcFini(); };
+
+            auto fonts = FcConfigGetFonts(nullptr, FcSetSystem);
+            if (fonts == nullptr)
+                return false;
+
+            for (int i = 0; i < fonts->nfont; ++i) {
+                auto font = fonts->fonts[i];
+                FcChar8 *file, *fullName;
+
+                if (FcPatternGetString(font, FC_FILE, 0, &file) != FcResultMatch) {
+                    continue;
+                }
+
+                if (FcPatternGetString(font, FC_FULLNAME, 0, &fullName) != FcResultMatch
+                    && FcPatternGetString(font, FC_FAMILY, 0, &fullName) != FcResultMatch) {
+                    continue;
+                }
+                
+                registerFont(reinterpret_cast<const char *>(fullName), reinterpret_cast<const char *>(file));
+            }
+
+            return true;
+        }
+    #endif
+
     void enumerateFonts() {
+        #if defined(IMHEX_HAS_FONTCONFIG)
+            if (enumerateFontConfig())
+                return;
+        #endif
+
         const std::array FontDirectories = {
             "/usr/share/fonts",
             "/usr/local/share/fonts",