CMake: improve detection and configuration of image libs

Also: fix old (pre 3.13) link_directories() usage

2 files changed, 49 insertions, 39 deletions

diff --git a/CMake/fl_create_example.cmake b/CMake/fl_create_example.cmake
index a245bb5ea..8071b5070 100644
--- a/CMake/fl_create_example.cmake
+++ b/CMake/fl_create_example.cmake
@@ -117,9 +117,9 @@ macro (CREATE_EXAMPLE NAME SOURCES LIBRARIES)
 
   if (FLTK_HAVE_CAIRO)
     if (CMAKE_VERSION VERSION_LESS "3.13")
-      link_directories (${TARGET_NAME} PUBLIC ${PKG_CAIRO_LIBRARY_DIRS})
+      link_directories    (${PKG_CAIRO_LIBRARY_DIRS})
     else()
-      target_link_directories (${TARGET_NAME} PUBLIC ${PKG_CAIRO_LIBRARY_DIRS})
+      target_link_directories (${TARGET_NAME} PRIVATE ${PKG_CAIRO_LIBRARY_DIRS})
     endif()
   endif (FLTK_HAVE_CAIRO)
 
diff --git a/CMake/options.cmake b/CMake/options.cmake
index 008088a45..cf50da6b8 100644
--- a/CMake/options.cmake
+++ b/CMake/options.cmake
@@ -168,11 +168,16 @@ if (OPTION_CAIRO OR OPTION_CAIROEXT)
     endif (OPTION_CAIROEXT)
     add_subdirectory (cairo)
 
-    # fl_debug_var (PKG_CAIRO_INCLUDE_DIRS)
-    # fl_debug_var (PKG_CAIRO_CFLAGS)
-    # fl_debug_var (PKG_CAIRO_STATIC_CFLAGS)
-    # fl_debug_var (PKG_CAIRO_LIBRARIES)
-    # fl_debug_var (PKG_CAIRO_STATIC_LIBRARIES)
+    if (0)
+      fl_debug_var (PKG_CAIRO_INCLUDE_DIRS)
+      fl_debug_var (PKG_CAIRO_CFLAGS)
+      fl_debug_var (PKG_CAIRO_LIBRARIES)
+      fl_debug_var (PKG_CAIRO_LIBRARY_DIRS)
+      fl_debug_var (PKG_CAIRO_STATIC_INCLUDE_DIRS)
+      fl_debug_var (PKG_CAIRO_STATIC_CFLAGS)
+      fl_debug_var (PKG_CAIRO_STATIC_LIBRARIES)
+      fl_debug_var (PKG_CAIRO_STATIC_LIBRARY_DIRS)
+    endif()
 
     include_directories (${PKG_CAIRO_INCLUDE_DIRS})
 
@@ -339,87 +344,92 @@ endif (debug_threads)
 unset (debug_threads)
 
 #######################################################################
-option (OPTION_USE_SYSTEM_ZLIB "use system zlib" ON)
+#  Image Library Options
+#######################################################################
+
+option (OPTION_USE_SYSTEM_ZLIB      "use system zlib"    ON)
+
+if (APPLE)
+  option (OPTION_USE_SYSTEM_LIBJPEG "use system libjpeg" OFF)
+  option (OPTION_USE_SYSTEM_LIBPNG  "use system libpng"  OFF)
+else ()
+  option (OPTION_USE_SYSTEM_LIBJPEG "use system libjpeg" ON)
+  option (OPTION_USE_SYSTEM_LIBPNG  "use system libpng"  ON)
+endif ()
+
+#######################################################################
+#  Image Library : ZLIB
+#######################################################################
 
 if (OPTION_USE_SYSTEM_ZLIB)
-  include (FindZLIB)
-endif (OPTION_USE_SYSTEM_ZLIB)
+  find_package (ZLIB)
+endif ()
 
-if (ZLIB_FOUND)
+if (OPTION_USE_SYSTEM_ZLIB AND ZLIB_FOUND)
+  set (FLTK_USE_BUILTIN_ZLIB FALSE)
   set (FLTK_ZLIB_LIBRARIES ${ZLIB_LIBRARIES})
   include_directories (${ZLIB_INCLUDE_DIRS})
-  set (FLTK_BUILTIN_ZLIB_FOUND FALSE)
 else()
   if (OPTION_USE_SYSTEM_ZLIB)
     message (STATUS "cannot find system zlib library - using built-in\n")
-  endif (OPTION_USE_SYSTEM_ZLIB)
+  endif ()
 
   add_subdirectory (zlib)
+  set (FLTK_USE_BUILTIN_ZLIB TRUE)
   set (FLTK_ZLIB_LIBRARIES fltk_z)
   set (ZLIB_INCLUDE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/zlib)
   include_directories (${CMAKE_CURRENT_SOURCE_DIR}/zlib)
-  set (FLTK_BUILTIN_ZLIB_FOUND TRUE)
-endif (ZLIB_FOUND)
+endif ()
 
 set (HAVE_LIBZ 1)
 
 #######################################################################
-if (APPLE)
-  option (OPTION_USE_SYSTEM_LIBJPEG "use system libjpeg" OFF)
-else ()
-  option (OPTION_USE_SYSTEM_LIBJPEG "use system libjpeg" ON)
-endif (APPLE)
 
 if (OPTION_USE_SYSTEM_LIBJPEG)
-  include (FindJPEG)
-endif (OPTION_USE_SYSTEM_LIBJPEG)
+  find_package (JPEG)
+endif ()
 
-if (JPEG_FOUND)
+if (OPTION_USE_SYSTEM_LIBJPEG AND JPEG_FOUND)
+  set (FLTK_USE_BUILTIN_JPEG FALSE)
   set (FLTK_JPEG_LIBRARIES ${JPEG_LIBRARIES})
   include_directories (${JPEG_INCLUDE_DIR})
-  set (FLTK_BUILTIN_JPEG_FOUND FALSE)
 else ()
   if (OPTION_USE_SYSTEM_LIBJPEG)
     message (STATUS "cannot find system jpeg library - using built-in\n")
-  endif (OPTION_USE_SYSTEM_LIBJPEG)
+  endif ()
 
   add_subdirectory (jpeg)
+  set (FLTK_USE_BUILTIN_JPEG TRUE)
   set (FLTK_JPEG_LIBRARIES fltk_jpeg)
   include_directories (${CMAKE_CURRENT_SOURCE_DIR}/jpeg)
-  set (FLTK_BUILTIN_JPEG_FOUND TRUE)
-endif (JPEG_FOUND)
+endif ()
 
 set (HAVE_LIBJPEG 1)
 
 #######################################################################
-if (APPLE)
-  option (OPTION_USE_SYSTEM_LIBPNG "use system libpng" OFF)
-else ()
-  option (OPTION_USE_SYSTEM_LIBPNG "use system libpng" ON)
-endif (APPLE)
 
 if (OPTION_USE_SYSTEM_LIBPNG)
-  include (FindPNG)
-endif (OPTION_USE_SYSTEM_LIBPNG)
+  find_package (PNG)
+endif ()
 
-if (PNG_FOUND)
+if (OPTION_USE_SYSTEM_LIBPNG AND PNG_FOUND)
+  set (FLTK_USE_BUILTIN_PNG FALSE)
   set (FLTK_PNG_LIBRARIES ${PNG_LIBRARIES})
   include_directories (${PNG_INCLUDE_DIR})
   add_definitions (${PNG_DEFINITIONS})
-  set (FLTK_BUILTIN_PNG_FOUND FALSE)
 else()
   if (OPTION_USE_SYSTEM_LIBPNG)
     message (STATUS "cannot find system png library - using built-in\n")
-  endif (OPTION_USE_SYSTEM_LIBPNG)
+  endif ()
 
   add_subdirectory (png)
+  set (FLTK_USE_BUILTIN_PNG TRUE)
   set (FLTK_PNG_LIBRARIES fltk_png)
   set (HAVE_PNG_H 1)
   set (HAVE_PNG_GET_VALID 1)
   set (HAVE_PNG_SET_TRNS_TO_ALPHA 1)
   include_directories (${CMAKE_CURRENT_SOURCE_DIR}/png)
-  set (FLTK_BUILTIN_PNG_FOUND TRUE)
-endif (PNG_FOUND)
+endif ()
 
 set (HAVE_LIBPNG 1)