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# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
# file LICENSE.rst or https://cmake.org/licensing for details.
#[=======================================================================[.rst:
FindPNG
-------
Finds libpng, the official reference library for the PNG image format.
.. note::
The PNG library depends on the ZLib compression library, which must be found
for this module to succeed.
Imported Targets
^^^^^^^^^^^^^^^^
.. versionadded:: 3.5
This module defines the following :ref:`Imported Targets`:
``PNG::PNG``
The libpng library, if found.
Result Variables
^^^^^^^^^^^^^^^^
This module sets the following variables:
``PNG_INCLUDE_DIRS``
Directory containing the PNG headers (e.g., ``png.h``).
``PNG_LIBRARIES``
PNG libraries required for linking.
``PNG_DEFINITIONS``
Compile definitions for using PNG, if any. They can be added with
:command:`target_compile_definitions` command when not using the ``PNG::PNG``
imported target.
``PNG_FOUND``
True if PNG library is found.
``PNG_VERSION_STRING``
The version of the PNG library found.
Obsolete Variables
^^^^^^^^^^^^^^^^^^
The following variables may also be set for backward compatibility:
``PNG_LIBRARY``
Path to the PNG library.
``PNG_INCLUDE_DIR``
Directory containing the PNG headers (same as ``PNG_INCLUDE_DIRS``).
Examples
^^^^^^^^
Finding PNG library and using it in a project:
.. code-block:: cmake
find_package(PNG)
target_link_libraries(project_target PRIVATE PNG::PNG)
#]=======================================================================]
cmake_policy(PUSH)
cmake_policy(SET CMP0159 NEW) # file(STRINGS) with REGEX updates CMAKE_MATCH_<n>
# Default install location on windows when installing from included cmake build
# From FindZLIB.cmake
set(_PNG_x86 "(x86)")
set(_PNG_INCLUDE_SEARCH_NORMAL
"$ENV{ProgramFiles}/libpng"
"$ENV{ProgramFiles${_PNG_x86}}/libpng")
set(_PNG_LIB_SEARCH_NORMAL
"$ENV{ProgramFiles}/libpng/lib"
"$ENV{ProgramFiles${_PNG_x86}}/libpng/lib")
unset(_PNG_x86)
if(PNG_FIND_QUIETLY)
set(_FIND_ZLIB_ARG QUIET)
endif()
find_package(ZLIB ${_FIND_ZLIB_ARG})
if(ZLIB_FOUND)
set(_PNG_VERSION_SUFFIXES 17 16 15 14 12)
list(APPEND _PNG_INCLUDE_PATH_SUFFIXES include/libpng)
foreach(v IN LISTS _PNG_VERSION_SUFFIXES)
list(APPEND _PNG_INCLUDE_PATH_SUFFIXES include/libpng${v})
endforeach()
find_path(PNG_PNG_INCLUDE_DIR png.h PATH_SUFFIXES ${_PNG_INCLUDE_PATH_SUFFIXES} PATHS ${_PNG_INCLUDE_SEARCH_NORMAL} )
mark_as_advanced(PNG_PNG_INCLUDE_DIR)
list(APPEND PNG_NAMES png libpng)
unset(PNG_NAMES_DEBUG)
if (PNG_FIND_VERSION MATCHES "^([0-9]+)\\.([0-9]+)(\\..*)?$")
set(_PNG_VERSION_SUFFIX_MIN "${CMAKE_MATCH_1}${CMAKE_MATCH_2}")
if (PNG_FIND_VERSION_EXACT)
set(_PNG_VERSION_SUFFIXES ${_PNG_VERSION_SUFFIX_MIN})
else ()
string(REGEX REPLACE
"${_PNG_VERSION_SUFFIX_MIN}.*" "${_PNG_VERSION_SUFFIX_MIN}"
_PNG_VERSION_SUFFIXES "${_PNG_VERSION_SUFFIXES}")
endif ()
unset(_PNG_VERSION_SUFFIX_MIN)
endif ()
foreach(v IN LISTS _PNG_VERSION_SUFFIXES)
list(APPEND PNG_NAMES png${v} libpng${v} libpng${v}_static)
list(APPEND PNG_NAMES_DEBUG png${v}d libpng${v}d libpng${v}_staticd)
endforeach()
unset(_PNG_VERSION_SUFFIXES)
# For compatibility with versions prior to this multi-config search, honor
# any PNG_LIBRARY that is already specified and skip the search.
if(NOT PNG_LIBRARY)
find_library(PNG_LIBRARY_RELEASE NAMES ${PNG_NAMES} NAMES_PER_DIR PATHS ${_PNG_LIB_SEARCH_NORMAL})
find_library(PNG_LIBRARY_DEBUG NAMES ${PNG_NAMES_DEBUG} NAMES_PER_DIR PATHS ${_PNG_LIB_SEARCH_NORMAL})
include(${CMAKE_CURRENT_LIST_DIR}/SelectLibraryConfigurations.cmake)
select_library_configurations(PNG)
mark_as_advanced(PNG_LIBRARY_RELEASE PNG_LIBRARY_DEBUG)
endif()
unset(PNG_NAMES)
unset(PNG_NAMES_DEBUG)
unset(_PNG_INCLUDE_PATH_SUFFIXES)
# Set by select_library_configurations(), but we want the one from
# find_package_handle_standard_args() below.
unset(PNG_FOUND)
if (PNG_LIBRARY AND PNG_PNG_INCLUDE_DIR)
# png.h includes zlib.h. Sigh.
set(PNG_INCLUDE_DIRS ${PNG_PNG_INCLUDE_DIR} ${ZLIB_INCLUDE_DIR} )
set(PNG_INCLUDE_DIR ${PNG_INCLUDE_DIRS} ) # for backward compatibility
set(PNG_LIBRARIES ${PNG_LIBRARY} ${ZLIB_LIBRARY})
if((CMAKE_SYSTEM_NAME STREQUAL "Linux") AND
("${PNG_LIBRARY}" MATCHES "\\${CMAKE_STATIC_LIBRARY_SUFFIX}$"))
list(APPEND PNG_LIBRARIES m)
endif()
if (CYGWIN)
if(BUILD_SHARED_LIBS)
# No need to define PNG_USE_DLL here, because it's default for Cygwin.
else()
set (PNG_DEFINITIONS -DPNG_STATIC)
set(_PNG_COMPILE_DEFINITIONS PNG_STATIC)
endif()
endif ()
if(NOT TARGET PNG::PNG)
add_library(PNG::PNG UNKNOWN IMPORTED)
set_target_properties(PNG::PNG PROPERTIES
INTERFACE_COMPILE_DEFINITIONS "${_PNG_COMPILE_DEFINITIONS}"
INTERFACE_INCLUDE_DIRECTORIES "${PNG_INCLUDE_DIRS}"
INTERFACE_LINK_LIBRARIES ZLIB::ZLIB)
if((CMAKE_SYSTEM_NAME STREQUAL "Linux") AND
("${PNG_LIBRARY}" MATCHES "\\${CMAKE_STATIC_LIBRARY_SUFFIX}$"))
set_property(TARGET PNG::PNG APPEND PROPERTY
INTERFACE_LINK_LIBRARIES m)
endif()
if(EXISTS "${PNG_LIBRARY}")
set_target_properties(PNG::PNG PROPERTIES
IMPORTED_LINK_INTERFACE_LANGUAGES "C"
IMPORTED_LOCATION "${PNG_LIBRARY}")
endif()
if(EXISTS "${PNG_LIBRARY_RELEASE}")
set_property(TARGET PNG::PNG APPEND PROPERTY
IMPORTED_CONFIGURATIONS RELEASE)
set_target_properties(PNG::PNG PROPERTIES
IMPORTED_LINK_INTERFACE_LANGUAGES_RELEASE "C"
IMPORTED_LOCATION_RELEASE "${PNG_LIBRARY_RELEASE}")
endif()
if(EXISTS "${PNG_LIBRARY_DEBUG}")
set_property(TARGET PNG::PNG APPEND PROPERTY
IMPORTED_CONFIGURATIONS DEBUG)
set_target_properties(PNG::PNG PROPERTIES
IMPORTED_LINK_INTERFACE_LANGUAGES_DEBUG "C"
IMPORTED_LOCATION_DEBUG "${PNG_LIBRARY_DEBUG}")
endif()
endif()
unset(_PNG_COMPILE_DEFINITIONS)
endif ()
if (PNG_PNG_INCLUDE_DIR AND EXISTS "${PNG_PNG_INCLUDE_DIR}/png.h")
file(STRINGS "${PNG_PNG_INCLUDE_DIR}/png.h" png_version_str REGEX "^#define[ \t]+PNG_LIBPNG_VER_STRING[ \t]+\".+\"")
string(REGEX REPLACE "^#define[ \t]+PNG_LIBPNG_VER_STRING[ \t]+\"([^\"]+)\".*" "\\1" PNG_VERSION_STRING "${png_version_str}")
unset(png_version_str)
endif ()
endif()
include(FindPackageHandleStandardArgs)
find_package_handle_standard_args(PNG
REQUIRED_VARS PNG_LIBRARY PNG_PNG_INCLUDE_DIR
VERSION_VAR PNG_VERSION_STRING)
cmake_policy(POP)
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