Add freetype dependency.

We are going to use freetype instead of the old custom TTF parser,
since the old parser has many annoying bugs when handling non-Latin
fonts and fixing it is not really worth the time.

On Windows, Freetype is built from a submodule.
On Linux and OS X, Freetype is provided together with the desktop,
though development files have to be installed separately.

.gitmodules

@@ -5,3 +5,6 @@
 [submodule "extlib/libpng"]
 	path = extlib/libpng
 	url = https://github.com/glennrp/libpng
+[submodule "extlib/libfreetype"]
+	path = extlib/libfreetype
+	url = http://git.sv.nongnu.org/r/freetype/freetype2.git

.travis.yml

@@ -3,7 +3,7 @@ os:
   - linux
   - osx
 install:
-  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then sudo add-apt-repository -y ppa:smspillaz/cmake-master; sudo add-apt-repository -y ppa:ondrej/php5; sudo apt-get update -qq; sudo apt-get install -q -y cmake cmake-data libpng12-dev zlib1g-dev libjson0-dev libfontconfig1-dev libgtkmm-2.4-dev libpangomm-1.4-dev libgl1-mesa-dev libglu-dev libglew-dev dpkg-dev; fi
+  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then sudo add-apt-repository -y ppa:smspillaz/cmake-master; sudo add-apt-repository -y ppa:ondrej/php5; sudo apt-get update -qq; sudo apt-get install -q -y cmake cmake-data libpng12-dev zlib1g-dev libjson0-dev libfontconfig1-dev libgtkmm-2.4-dev libpangomm-1.4-dev libgl1-mesa-dev libglu-dev libglew-dev libfreetype6-dev dpkg-dev; fi
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew update; brew upgrade cmake libpng; fi
 script:
   - mkdir cbuild

CMakeLists.txt

@@ -67,6 +67,32 @@ CHECK_INCLUDE_FILE("stdint.h" HAVE_STDINT_H)
 find_package(OpenGL REQUIRED)
 
 if(WIN32)
+    # We don't want any of the subprojects to install anything.
+    # We don't actually install anything on Windows (so overriding
+    # this is OK), but the combination of freetype's and png/zlib's
+    # CMakeLists.txt produces harmless but annoying CMake errors.
+    macro(install)
+    endmacro()
+
+    # Configure Freetype first. If done later, it will notice that
+    # zlib is available, try to use it and promptly break on MSVC
+    # in a very obscure way. Given that the only use of zlib, bzip2
+    # and png support is in support for extremely obsolete Unix fonts,
+    # we don't care.
+    find_package(Freetype)
+
+    if(NOT FREETYPE_FOUND)
+        message(STATUS "Using in-tree libfreetype")
+
+        add_subdirectory(extlib/libfreetype)
+
+        set(FREETYPE_LIBRARY
+            freetype)
+        set(FREETYPE_INCLUDE_DIRS
+            "${CMAKE_SOURCE_DIR}/extlib/libfreetype/include")
+        find_package(Freetype REQUIRED)
+    endif()
+
     find_package(ZLIB)
 
     if(NOT ZLIB_FOUND)
@@ -109,6 +135,7 @@ if(WIN32)
     endif()
 elseif(APPLE)
     find_package(PNG REQUIRED)
+    find_package(Freetype REQUIRED)
     find_library(APPKIT_LIBRARY AppKit REQUIRED)
 else() # Linux and compatible systems
     find_package(SpaceWare)
@@ -120,6 +147,7 @@ else() # Linux and compatible systems
     pkg_check_modules(FONTCONFIG REQUIRED fontconfig)
     pkg_check_modules(JSONC REQUIRED json-c)
     pkg_check_modules(GLEW REQUIRED glew)
+    pkg_check_modules(FREETYPE REQUIRED freetype2)
 
     set(HAVE_GTK TRUE)
     if(GUI STREQUAL "gtk3")

README.md

@@ -24,13 +24,13 @@ Building on Linux
 
 ### Building for Linux
 
-You will need CMake, libpng, zlib, json-c, fontconfig, gtkmm 2.4, pangomm 1.4,
-OpenGL and OpenGL GLU.
+You will need CMake, libpng, zlib, json-c, fontconfig, freetype, gtkmm 2.4,
+pangomm 1.4, OpenGL and OpenGL GLU.
 On a Debian derivative (e.g. Ubuntu) these can be installed with:
 
-    apt-get install libpng12-dev libjson-c-dev libfontconfig1-dev \
-                    libgtkmm-2.4-dev libpangomm-1.4-dev libgl-dev libglu-dev \
-                    libglew-dev cmake
+    apt-get install libpng12-dev libjson-c-dev libfreetype6-dev \
+                    libfontconfig1-dev libgtkmm-2.4-dev libpangomm-1.4-dev \
+                    libgl-dev libglu-dev libglew-dev cmake
 
 After that, build SolveSpace as following:
 

extlib/libfreetype

@@ -0,0 +1 @@
+Subproject commit 44accb9e2e5b00696cf50a869b68afa2ce3dd389

src/CMakeLists.txt

@@ -2,16 +2,12 @@
 
 include_directories(
     ${OPENGL_INCLUDE_DIR}
-    ${PNG_INCLUDE_DIRS})
+    ${PNG_INCLUDE_DIRS}
+    ${FREETYPE_INCLUDE_DIRS})
 
 link_directories(
-    ${PNG_LIBRARY_DIRS})
-
-add_definitions(
-    ${PNG_CFLAGS_OTHER})
-
-link_directories(
-    ${PNG_LIBRARY_DIRS})
+    ${PNG_LIBRARY_DIRS}
+    ${FREETYPE_LIBRARY_DIRS})
 
 add_definitions(
     ${PNG_CFLAGS_OTHER})
@@ -307,6 +303,7 @@ target_link_libraries(solvespace
     "${OPENGL_LIBRARIES}"
     "${PNG_LIBRARIES}"
     "${ZLIB_LIBRARIES}"
+    "${FREETYPE_LIBRARIES}"
     "${platform_LIBRARIES}")
 
 if(WIN32 AND NOT MINGW)