add new thirdparty library, freetype

CMakeLists.txt

@@ -73,6 +73,7 @@ target_sources(nf7
     common/file_base.hh
     common/file_holder.hh
     common/file_holder.cc
+    common/font_queue.hh
     common/future.hh
     common/generic_context.hh
     common/generic_history.hh
@@ -161,6 +162,7 @@ target_sources(nf7
 )
 target_link_libraries(nf7
   PRIVATE
+    freetype
     glew
     glfw
     imgui

common/font_queue.hh

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <functional>
+#include <memory>
+
+#include <ft2build.h>
+#include FT_FREETYPE_H
+
+#include "nf7.hh"
+
+
+namespace nf7::font {
+
+class Queue : public nf7::File::Interface {
+ public:
+  using Task = std::function<void(FT_Library)>;
+  Queue() = default;
+  Queue(const Queue&) = delete;
+  Queue(Queue&&) = delete;
+  Queue& operator=(const Queue&) = delete;
+  Queue& operator=(Queue&&) = delete;
+
+  // thread-safe
+  virtual void Push(const std::shared_ptr<nf7::Context>&, Task&&) noexcept = 0;
+
+  virtual std::shared_ptr<Queue> self() noexcept = 0;
+};
+
+}  // namespace nf7::font

thirdparty/CMakeLists.txt

@@ -10,6 +10,24 @@ else()
 endif()
 
 
+# ---- FreeType ----
+# repository:
+# license   : The FreeType License
+
+FetchContent_Declare(
+  freetype
+  URL "https://gitlab.freedesktop.org/freetype/freetype/-/archive/VER-2-12-1/freetype-VER-2-12-1.zip"
+)
+
+set(FT_DISABLE_ZLIB     ON)
+set(FT_DISABLE_BZIP2    ON)
+set(FT_DISABLE_PNG      ON)
+set(FT_DISABLE_HARFBUZZ ON)
+set(FT_DISABLE_BROTLI   ON)
+set(FT_ENABLE_ERROR_STRINGS ON)
+FetchContent_MakeAvailable(freetype)
+
+
 # ---- GLEW ----
 # repository: https://github.com/Perlmint/glew-cmake
 # license   :  Modified BSD License, the Mesa 3-D License (MIT) and the Khronos License (MIT).