using libpng

CMakeLists.txt

@@ -54,7 +54,7 @@ endif(Boost_FOUND)
 
 if(OpenMP_CXX_FOUND)
     target_link_libraries(Almond PUBLIC OpenMP::OpenMP_CXX)
-    target_link_libraries(Almond PUBLIC ${OpenMP_CXX_FLAGS})
+    target_compile_options(Almond PUBLIC ${OpenMP_CXX_FLAGS})
 endif()
 
 

libalmond/CMakeLists.txt

@@ -11,7 +11,7 @@ add_subdirectory(../libmandel ./libmandel)
 #set(Boost_DEBUG 1)
 set(Boost_USE_STATIC_LIBS ON)
 find_package(Boost 1.65 REQUIRED)
-find_package(PNG REQUIRED)
+find_package(PNG)
 
 set(CMAKE_CXX_STANDARD 17)
 
@@ -21,12 +21,32 @@ FILE(GLOB libalmondheaders include/*.h)
 
 add_library(libalmond STATIC ${libalmondsources})
 target_include_directories(libalmond PUBLIC "include")
-target_include_directories(libalmond SYSTEM PUBLIC ${FFMPEG_INCLUDE_DIRS})
-target_include_directories(libalmond SYSTEM PUBLIC ${PNG_INCLUDE_DIRS})
 target_link_libraries(libalmond PUBLIC mandel)
-target_link_libraries(libalmond PUBLIC ${FFMPEG_LIBRARIES})
-target_link_libraries(libalmond PUBLIC ${PNG_LIBRARIES})
 set_target_properties(libalmond PROPERTIES OUTPUT_NAME almond)
 
+target_include_directories(libalmond SYSTEM PUBLIC ${FFMPEG_INCLUDE_DIRS})
+target_link_libraries(libalmond PUBLIC ${FFMPEG_LIBRARIES})
 
+if (PNG_FOUND)
+    target_include_directories(libalmond SYSTEM PUBLIC ${PNG_INCLUDE_DIRS})
+    target_link_libraries(libalmond PUBLIC ${PNG_LIBRARIES})
+else()
+    set(PNG_BUILD_ZLIB ON CACHE BOOL "build zlib ourselves")
+    add_subdirectory(zlib-1.2.11)
+    set(ZLIB_LIBRARY zlibstatic)
+    foreach(header ${ZLIB_PUBLIC_HDRS})
+        get_filename_component(the_incluude ${header} DIRECTORY)
+        list(APPEND ZLIB_PUB_INCLUDE ${the_incluude})
+    endforeach()
+    set(ZLIB_INCLUDE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/zlib-1.2.11 ${ZLIB_PUB_INCLUDE} )
+    
+    add_subdirectory(lpng1637)
+    foreach(header ${libpng_public_hdrs})
+        get_filename_component(the_incluude ${header} DIRECTORY)
+        list(APPEND PNG_PUB_INCLUDE ${the_incluude})
+    endforeach()
+    target_include_directories(libalmond PRIVATE ${PNG_PUB_INCLUDE})
+    target_include_directories(libalmond PRIVATE ${ZLIB_INCLUDE_DIR})
+    target_link_libraries(libalmond PRIVATE png_static)
+endif()