CMake: build shared libs with OPTION_CAIROEXT (issue #250)

- remove separate libfltk_cairo to avoid cyclic dependencies, but
- keep a dummy libfltk_cairo in 1.4.0 for backwards compatibility
- move cairo/Fl_Cairo.cxx to src/Fl_Cairo.cxx
- add preliminary Cairo support for Visual Studio (MSVC)

Static linking is not affected by this change, but users building
with hand-made Makefiles will have to remove libfltk_cairo starting
with FLTK 1.4.0. The dummy library can be linked for backwards
compatibility but it will be removed later (in 1.4.x or 1.5.0).

The shared FLTK library libfltk.{so|dylib|dll|..} depends on libcairo
if and only if FLTK is built with one of the Cairo options. This has
always been the case for OPTION_CAIROEXT but is now also true if only
OPTION_CAIRO is selected, i.e. FLTK programs linked with a Cairo
enabled shared FLTK library will also be linked with libcairo. The same
is true for configure options --enable-cairo and --enable-cairoext,
respectively.

Preliminary Cairo support for MSVC now detects a Cairo installation
using the CMake variable FLTK_CAIRO_DIR which must be set by the user.
Note that this feature is temporary and may be changed in the future
for a better and more comfortable version.

1 files changed, 14 insertions, 1 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 40671d392..741d1f5b8 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -172,6 +172,10 @@ set (CPPFILES
   screen_xywh.cxx
 )
 
+if (FLTK_HAVE_CAIRO) # OPTION_CAIRO or OPTION_CAIROEXT
+  list (APPEND CPPFILES Fl_Cairo.cxx)
+endif ()
+
 # find all header files in source directory <FL/...>
 file (GLOB
   HEADER_FILES
@@ -616,6 +620,10 @@ if (HAVE_XRENDER)
   list (APPEND OPTIONAL_LIBS ${X11_Xrender_LIB})
 endif (HAVE_XRENDER)
 
+if (FLTK_HAVE_CAIRO) # OPTION_CAIRO or OPTION_CAIROEXT
+  list (APPEND OPTIONAL_LIBS ${PKG_CAIRO_LIBRARIES})
+endif()
+
 if (USE_PANGO)
   ### FIXME ###  This needs to use the PKG_* variables directly
   list (APPEND OPTIONAL_LIBS ${HAVE_LIB_PANGO} ${HAVE_LIB_PANGOCAIRO})
@@ -694,6 +702,10 @@ endif (UNIX AND OPTION_USE_WAYLAND)
 FL_ADD_LIBRARY (fltk STATIC "${STATIC_FILES}")
 target_link_libraries (fltk ${OPTIONAL_LIBS})
 
+if (FLTK_HAVE_CAIRO)
+  fl_target_link_directories (fltk PUBLIC "${PKG_CAIRO_LIBRARY_DIRS}")
+endif()
+
 #######################################################################
 
 FL_ADD_LIBRARY (fltk_forms STATIC "${FORMS_FILES}")
@@ -738,7 +750,8 @@ endif (OPENGL_FOUND)
 if (OPTION_BUILD_SHARED_LIBS AND NOT MSVC)
 
   FL_ADD_LIBRARY (fltk SHARED "${SHARED_FILES}")
-  target_link_libraries (fltk_SHARED ${OPTIONAL_LIBS})
+  target_link_libraries (fltk_SHARED ${OPTIONAL_LIBS} ${PKG_CAIRO_LIBRARIES})
+  fl_target_link_directories (fltk_SHARED PUBLIC "${PKG_CAIRO_LIBRARY_DIRS}")
 
   ###################################################################