RFC: Better Text Rendering for cairo / lua

.github/workflows/build-and-test-linux.yaml

@@ -137,6 +137,7 @@ jobs:
             -DBUILD_LUA_CAIRO=ON                 \
             -DBUILD_LUA_IMLIB2=ON                \
             -DBUILD_LUA_RSVG=${RSVG_ENABLED}     \
+            -DBUILD_LUA_TEXT=ON                  \
             -DBUILD_MYSQL=ON                     \
             -DBUILD_NVIDIA=ON                    \
             -DBUILD_PULSEAUDIO=ON                \

AUTHORS

@@ -313,6 +313,9 @@ Mikko Sysikaski <sisu at users dot sourceforge dot net>
 Sceptik <sceptik at users dot sourceforge dot net>
   --quiet patch
 
+Simon Lees <sflees at suse dot de>
+  lua text
+
 Stepan Zastupov <redchrom at gmail dot com>
   WiFi signal level detection support on FreeBSD
 

Dockerfile

@@ -16,6 +16,9 @@ RUN apt-get update \
   libcairo2-dev \
   libcurl4-openssl-dev \
   libdbus-glib-1-dev \
+  libfontconfig-dev \
+  libfreetype-dev \
+  libharfbuzz-dev \
   libical-dev \
   libimlib2-dev \
   libircclient-dev \
@@ -76,6 +79,7 @@ RUN sh -c 'if [ "$X11" = "yes" ] ; then \
   -DBUILD_LUA_CAIRO=ON \
   -DBUILD_LUA_IMLIB2=ON \
   -DBUILD_LUA_RSVG=ON \
+  -DBUILD_LUA_TEXT=ON \
   -DBUILD_MYSQL=ON \
   -DBUILD_NVIDIA=ON \
   -DBUILD_PULSEAUDIO=ON \
@@ -98,6 +102,7 @@ RUN sh -c 'if [ "$X11" = "yes" ] ; then \
   -DBUILD_LUA_CAIRO=ON \
   -DBUILD_LUA_IMLIB2=ON \
   -DBUILD_LUA_RSVG=ON \
+  -DBUILD_LUA_TEXT=ON \
   -DBUILD_MYSQL=ON \
   -DBUILD_PULSEAUDIO=ON \
   -DBUILD_RSS=ON \
@@ -121,6 +126,9 @@ RUN apt-get update \
   libcairo2 \
   libcurl4 \
   libdbus-glib-1-2 \
+  libfontconfig1 \
+  libfreetype6 \
+  libharfbuzz-gobject0 \
   libical3 \
   libimlib2 \
   libircclient1 \

appimage/build.sh

@@ -44,6 +44,7 @@ cmake -G Ninja                         \
   -DBUILD_LUA_CAIRO=ON                 \
   -DBUILD_LUA_IMLIB2=ON                \
   -DBUILD_LUA_RSVG=ON                  \
+  -DBUILD_LUA_TEXT=ON                  \
   -DBUILD_MYSQL=ON                     \
   -DBUILD_NVIDIA=ON                    \
   -DBUILD_PULSEAUDIO=ON                \

cmake/ConkyBuildOptions.cmake

@@ -204,6 +204,7 @@ endif(OWN_WINDOW)
 option(BUILD_LUA_CAIRO "Build cairo bindings for Lua" false)
 option(BUILD_LUA_IMLIB2 "Build Imlib2 bindings for Lua" false)
 option(BUILD_LUA_RSVG "Build rsvg bindings for Lua" false)
+option(BUILD_LUA_TEXT "Build Fontconfig Freetype and Harfbuzz bindings for Lua" false)
 
 option(BUILD_AUDACIOUS "Build audacious (music player) support" false)
 

cmake/ConkyPlatformChecks.cmake

@@ -478,6 +478,17 @@ if(BUILD_X11)
     set(luarsvg_libs ${RSVG_LIBRARIES} ${LUA_LIBRARIES})
     set(luarsvg_includes ${RSVG_INCLUDE_DIRS} ${LUA_INCLUDE_DIR})
   endif(BUILD_LUA_RSVG)
+  if(BUILD_LUA_TEXT)
+    if(FREETYPE_INCLUDE_DIR_freetype2)
+      set(FREETYPE_FOUND true)
+    else(FREETYPE_INCLUDE_DIR_freetype2)
+      message(FATAL_ERROR "Unable to find freetype library")
+    endif(FREETYPE_INCLUDE_DIR_freetype2)
+    PKG_CHECK_MODULES(FONTCONFIG REQUIRED fontconfig)
+    PKG_CHECK_MODULES(HARFBUZZ REQUIRED harfbuzz)
+    set(luatext_libs ${FREETYPE_LIBRARIES} ${FONTCONFIG_LIBRARIES} ${HARFBUZZ_LIBRARIES} ${LUA_LIBRARIES})
+    set(luatext_includes ${FREETYPE_INCLUDE_DIR_freetype2} ${FONTCONFIG_INCLUDE_DIRS} ${HARFBUZZ_INCLUDE_DIRS} ${LUA_INCLUDE_DIRS})
+  endif(BUILD_LUA_TEXT)
 endif(BUILD_X11)
 
 if(BUILD_AUDACIOUS)

cmake/config.h.in

@@ -127,6 +127,8 @@
 
 #cmakedefine BUILD_LUA_RSVG 1
 
+#cmakedefine BUILD_LUA_TEXT 1
+
 #cmakedefine BUILD_IBM 1
 
 #cmakedefine BUILD_RSS 1

lua/CMakeLists.txt

@@ -75,6 +75,7 @@ if(BUILD_X11)
     print_target_properties(conky-rsvg)
   endif(BUILD_LUA_RSVG)
 
+
   if(BUILD_LUA_CAIRO AND BUILD_LUA_IMLIB2)
     include_directories(${luacairo_includes} ${luaimlib2_includes}
                         ${CMAKE_CURRENT_SOURCE_DIR})
@@ -90,6 +91,22 @@ if(BUILD_X11)
                           toluapp_lib_static)
     set(lua_libs ${lua_libs} conky-cairo_imlib2_helper)
   endif(BUILD_LUA_CAIRO AND BUILD_LUA_IMLIB2)
+
+  if(BUILD_LUA_CAIRO AND BUILD_LUA_TEXT)
+    include_directories(${luacairo_includes} ${luatext_includes}
+                        ${CMAKE_CURRENT_SOURCE_DIR})
+    wrap_tolua(luacairo_text_helper_src cairo_text_helper.pkg)
+
+    add_library(conky-cairo_text_helper SHARED ${luacairo_text_helper_src})
+    set_target_properties(conky-cairo_text_helper
+                          PROPERTIES OUTPUT_NAME "cairo_text_helper")
+
+    target_link_libraries(conky-cairo_text_helper
+                          ${luacairo_libs}
+                          ${luatext_libs}
+                          toluapp_lib_static)
+    set(lua_libs ${lua_libs} conky-cairo_text_helper)
+  endif(BUILD_LUA_CAIRO AND BUILD_LUA_TEXT)
 endif(BUILD_X11)
 
 install(TARGETS ${lua_libs}

lua/cairo_text_helper.pkg

@@ -0,0 +1,35 @@
+$#include <cairo.h>
+$#include <libcairo_text_helper.h>
+
+typedef struct _FontData {
+  cairo_font_face_t *cairo_ft_face;
+  hb_font_t *hb_ft_font;
+  hb_face_t *hb_ft_face;
+  int font_size;
+  /* Internally the following two are pointers */
+  /* Stored here so they can be freed later */
+  FT_Library ft_library;
+  FT_Face ft_face;
+}FontData;
+
+typedef enum _cairo_text_alignment {
+  CAIRO_TEXT_ALIGN_LEFT = 0,
+  CAIRO_TEXT_ALIGN_RIGHT,
+  CAIRO_TEXT_ALIGN_CENTER
+} cairo_text_alignment_t;
+
+FontData * cairo_text_hp_load_font(const char *font, int font_size);
+
+void cairo_text_hp_destroy_font(FontData *font);
+
+void cairo_text_hp_simple_show(cairo_t *cr, int x, int y, const char *text, FontData *font);
+void cairo_text_hp_simple_show_center(cairo_t *cr, int x, int y, const char *text, FontData *font);
+void cairo_text_hp_simple_show_right(cairo_t *cr, int x, int y, const char *text, FontData *font);
+
+void cairo_text_hp_intl_show(cairo_t *cr, int x, int y, cairo_text_alignment_t alignment, const char *text, FontData *font,
+                             const char *direction, const char *script, const char *language);
+
+int cairo_text_hp_text_width(const char *text, FontData *font, 
+                             const char *direction, const char *script, const char *language);
+
+int cairo_text_hp_simple_text_width(const char *text, FontData *font);