initial commit

cmake/libraries/libpng.cmake

@@ -0,0 +1,30 @@
+if(PROJECT_ENABLE_LIBPNG)
+  if(PROJECT_BUILD)
+    add_definitions(-DPROJECT_ENABLE_PNG)
+
+    find_package(PNG ${LIBPNG_VERSION} REQUIRED )
+
+    include_directories(${PNG_INCLUDE_DIRS})
+
+    link_libraries(PNG::PNG)
+  elseif(NOT PROJECT_IS_MINGW)
+    ExternalProject_Add(libpng_project
+      PREFIX external
+      URL ${PROJECT_3RD_PARTY_DIR}/libpng-v${LIBPNG_VERSION}.tar.gz
+      URL_HASH SHA256=${LIBPNG_HASH}
+      LIST_SEPARATOR |
+      CMAKE_ARGS ${PROJECT_EXTERNAL_CMAKE_FLAGS}
+        -DBUILD_SHARED_LIBS=${PROJECT_BUILD_SHARED_LIBS}
+        -DBUILD_STATIC_LIBS=ON
+        -DCMAKE_OSX_ARCHITECTURES=${CMAKE_OSX_ARCHITECTURES}
+        -DENABLE_SHARED=${PROJECT_BUILD_SHARED_LIBS}
+        -DPNG_SHARED=ON
+        -DPNG_STATIC=ON
+        -DPNG_TESTS=OFF
+        -DPNG_TOOLS=OFF
+    )
+
+    list(APPEND PROJECT_DEPENDENCIES libpng_project)
+  endif()
+endif()
+