# CMakeLists.txt

# Copyright (C) 2007,2009-2016 Glenn Randers-Pehrson
# Written by Christian Ehrlicher, 2007
# Revised by Roger Lowman, 2009-2010
# Revised by Clifford Yapp, 2011-2012
# Revised by Roger Leigh, 2016

# This code is released under the libpng license.
# For conditions of distribution and use, see the disclaimer
# and license in png.h

cmake_minimum_required(VERSION 2.8.3)
cmake_policy(VERSION 2.8.3)

# Set MacOSX @rpath usage globally.
if (POLICY CMP0020)
  cmake_policy(SET CMP0020 NEW)
endif(POLICY CMP0020)
if (POLICY CMP0042)
  cmake_policy(SET CMP0042 NEW)
endif(POLICY CMP0042)
# Use new variable expansion policy.
if (POLICY CMP0053)
  cmake_policy(SET CMP0053 NEW)
endif(POLICY CMP0053)
if (POLICY CMP0054)
  cmake_policy(SET CMP0054 NEW)
endif(POLICY CMP0054)

set(CMAKE_CONFIGURATION_TYPES "Release;Debug;MinSizeRel;RelWithDebInfo")

enable_testing()

set(PNGLIB_MAJOR 1)
set(PNGLIB_MINOR 5)
set(PNGLIB_RELEASE 28)
set(PNGLIB_NAME libpng${PNGLIB_MAJOR}${PNGLIB_MINOR})
set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_RELEASE})


# Needed packages. Since WIN32 (except mingw) uses the included zlib
# version, find_package would fail with an error message. Since
# all variables are already set in this case, the find package
# is actually not necessary in this case, so just ignore it
if(NOT WIN32 OR MINGW)
    find_package(ZLIB REQUIRED)
    include_directories(${ZLIB_INCLUDE_DIR})
endif()

if(NOT WIN32)
  find_library(M_LIBRARY
    NAMES m
    PATHS /usr/lib /usr/local/lib
  )
  if(NOT M_LIBRARY)
    message(STATUS "math lib 'libm' not found; floating point support disabled")
    set(M_LIBRARY "")
  endif()
else()
  # not needed on windows
  set(M_LIBRARY "")
endif()

# COMMAND LINE OPTIONS
option(PNG_SHARED "Build shared lib" ON)
option(PNG_STATIC "Build static lib" ON)
option(PNG_TESTS  "Build libpng tests" ON)

# Many more configuration options could be added here
option(PNG_FRAMEWORK "Build OS X framework" OFF)
option(PNG_DEBUG     "Build with debug output" OFF)
option(PNGARG        "Disable ANSI-C prototypes" OFF)

set(DFA_XTRA "" CACHE FILEPATH "File containing extra configuration settings")

# SET LIBNAME
set(PNG_LIB_NAME png${PNGLIB_MAJOR}${PNGLIB_MINOR})

# to distinguish between debug and release lib
set(CMAKE_DEBUG_POSTFIX "d")

include(CheckCSourceCompiles)
option(ld-version-script "Enable linker version script" ON)
if(ld-version-script AND NOT APPLE)
  # Check if LD supports linker scripts.
  file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/conftest.map" "VERS_1 {
        global: sym;
        local: *;
};

VERS_2 {
        global: sym2;
                main;
} VERS_1;
")
  set(CMAKE_REQUIRED_FLAGS_SAVE ${CMAKE_REQUIRED_FLAGS})
  set(CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS} "-Wl,--version-script='${CMAKE_CURRENT_BINARY_DIR}/conftest.map'")
  check_c_source_compiles("void sym(void) {}
void sym2(void) {}
int main(void) {return 0;}
" HAVE_LD_VERSION_SCRIPT)
  if(NOT HAVE_LD_VERSION_SCRIPT)
    set(CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS_SAVE} "-Wl,-M -Wl,${CMAKE_CURRENT_BINARY_DIR}/conftest.map")
  check_c_source_compiles("void sym(void) {}
void sym2(void) {}
int main(void) {return 0;}
" HAVE_SOLARIS_LD_VERSION_SCRIPT)
  endif()
  set(CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS_SAVE})
  file(REMOVE "${CMAKE_CURRENT_BINARY_DIR}/conftest.map")
endif()

find_program(AWK NAMES gawk awk)

include_directories(${CMAKE_CURRENT_BINARY_DIR})

if(NOT AWK)
  # No awk available to generate sources; use pre-built pnglibconf.h
  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.h.prebuilt
                 ${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h)
  add_custom_target(genfiles) # Dummy
else()
  include(CMakeParseArguments)
  # Generate .chk from .out with awk
  # generate_chk(INPUT inputfile OUTPUT outputfile [DEPENDS dep1 [dep2...]])
  function(generate_chk)
    set(options)
    set(oneValueArgs INPUT OUTPUT)
    set(multiValueArgs DEPENDS)
    cmake_parse_arguments(_GC "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
    if (NOT _GC_INPUT)
      message(FATAL_ERROR "Invalid arguments.  generate_out requires input.")
    endif()
    if (NOT _GC_OUTPUT)
      message(FATAL_ERROR "Invalid arguments.  generate_out requires output.")
    endif()

    add_custom_command(OUTPUT "${_GC_OUTPUT}"
                       COMMAND "${CMAKE_COMMAND}"
                               "-DINPUT=${_GC_INPUT}"
                               "-DOUTPUT=${_GC_OUTPUT}"
                               -P "${CMAKE_CURRENT_BINARY_DIR}/scripts/genchk.cmake"
                       DEPENDS "${_GC_INPUT}" ${_GC_DEPENDS}
                       WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
  endfunction()

  # Generate .out from .c with awk
  # generate_out(INPUT inputfile OUTPUT outputfile [DEPENDS dep1 [dep2...]])
  function(generate_out)
    set(options)
    set(oneValueArgs INPUT OUTPUT)
    set(multiValueArgs DEPENDS)
    cmake_parse_arguments(_GO "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
    if (NOT _GO_INPUT)
      message(FATAL_ERROR "Invalid arguments.  generate_out requires input.")
    endif()
    if (NOT _GO_OUTPUT)
      message(FATAL_ERROR "Invalid arguments.  generate_out requires output.")
    endif()

    add_custom_command(OUTPUT "${_GO_OUTPUT}"
                       COMMAND "${CMAKE_COMMAND}"
                               "-DINPUT=${_GO_INPUT}"
                               "-DOUTPUT=${_GO_OUTPUT}"
                               -P "${CMAKE_CURRENT_BINARY_DIR}/scripts/genout.cmake"
                       DEPENDS "${_GO_INPUT}" ${_GO_DEPENDS}
                       WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
  endfunction()

  # Generate specific source file with awk
  # generate_source(OUTPUT outputfile [DEPENDS dep1 [dep2...]])
  function(generate_source)
    set(options)
    set(oneValueArgs OUTPUT)
    set(multiValueArgs DEPENDS)
    cmake_parse_arguments(_GSO "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
    if (NOT _GSO_OUTPUT)
      message(FATAL_ERROR "Invalid arguments.  generate_source requires output.")
    endif()

    add_custom_command(OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/${_GSO_OUTPUT}"
                       COMMAND "${CMAKE_COMMAND}"
                               "-DOUTPUT=${_GSO_OUTPUT}"
                               -P "${CMAKE_CURRENT_BINARY_DIR}/scripts/gensrc.cmake"
                       DEPENDS ${_GSO_DEPENDS}
                       WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
  endfunction()

  # Copy file
  function(generate_copy source destination)
    add_custom_command(OUTPUT "${destination}"
                       COMMAND "${CMAKE_COMMAND}" -E remove "${destination}"
                       COMMAND "${CMAKE_COMMAND}" -E copy "${source}"
                                                          "${destination}"
                       DEPENDS "${source}")
  endfunction()

  # Generate scripts/pnglibconf.h
  generate_source(OUTPUT "scripts/pnglibconf.c"
                  DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.dfa"
                          "${CMAKE_CURRENT_SOURCE_DIR}/scripts/options.awk"
                          "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h")

  # Generate pnglibconf.c
  generate_source(OUTPUT "pnglibconf.c"
                  DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.dfa"
                          "${CMAKE_CURRENT_SOURCE_DIR}/scripts/options.awk"
                          "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h")

  generate_out(INPUT "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.c"
               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out")

  # Generate pnglibconf.h
  generate_source(OUTPUT "pnglibconf.h"
                  DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out"
                          ${PNGLIBCONF_H_EXTRA_DEPENDS})

  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/sym.c"
               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/sym.out"
               DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h")

  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/symbols.c"
               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.out"
               DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/png.h"
                       "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h"
                       "${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.h.prebuilt")

  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/vers.c"
               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/vers.out"
               DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/png.h"
                       "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h"
                       "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h")

  generate_chk(INPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.out"
               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.chk"
               DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/scripts/checksym.awk"
                       "${CMAKE_CURRENT_SOURCE_DIR}/scripts/symbols.def")

  add_custom_target(symbol-check DEPENDS
                    "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.chk")

  generate_copy("${CMAKE_CURRENT_BINARY_DIR}/scripts/sym.out"
                "${CMAKE_CURRENT_BINARY_DIR}/libpng.sym")
  generate_copy("${CMAKE_CURRENT_BINARY_DIR}/scripts/vers.out"
                "${CMAKE_CURRENT_BINARY_DIR}/libpng.vers")

  add_custom_target(genvers DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/libpng.vers")
  add_custom_target(gensym DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/libpng.sym")

  add_custom_target("genprebuilt"
                    COMMAND "${CMAKE_COMMAND}"
                            "-DOUTPUT=scripts/pnglibconf.h.prebuilt"
                            -P "${CMAKE_CURRENT_BINARY_DIR}/scripts/gensrc.cmake"
                    WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")

  # A single target handles generation of all generated files.  If
  # they are dependend upon separately by multiple targets, this
  # confuses parallel make (it would require a separate top-level
  # target for each file to track the dependencies properly).
  add_custom_target(genfiles DEPENDS
    "${CMAKE_CURRENT_BINARY_DIR}/libpng.sym"
    "${CMAKE_CURRENT_BINARY_DIR}/libpng.vers"
    "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.c"
    "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h"
    "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out"
    "${CMAKE_CURRENT_BINARY_DIR}/scripts/pnglibconf.c"
    "${CMAKE_CURRENT_BINARY_DIR}/scripts/sym.out"
    "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.chk"
    "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.out"
    "${CMAKE_CURRENT_BINARY_DIR}/scripts/vers.out")
endif(NOT AWK)

# OUR SOURCES
set(libpng_public_hdrs
  png.h
  pngconf.h
  "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h"
)
set(libpng_private_hdrs
  pngpriv.h
  pngdebug.h
  pnginfo.h
  pngstruct.h
)
set(libpng_sources
  ${libpng_public_hdrs}
  ${libpng_private_hdrs}
  png.c
  pngerror.c
  pngget.c
  pngmem.c
  pngpread.c
  pngread.c
  pngrio.c
  pngrtran.c
  pngrutil.c
  pngset.c
  pngtrans.c
  pngwio.c
  pngwrite.c
  pngwtran.c
  pngwutil.c
)
set(pngtest_sources
  pngtest.c
)
set(pngvalid_sources
  contrib/libtests/pngvalid.c
)

if(MSVC)
  add_definitions(-D_CRT_SECURE_NO_DEPRECATE)
endif(MSVC)

if(PNG_DEBUG)
  add_definitions(-DPNG_DEBUG)
endif()

# NOW BUILD OUR TARGET
include_directories(${CMAKE_CURRENT_SOURCE_DIR} ${ZLIB_INCLUDE_DIR})

unset(PNG_LIB_TARGETS)

if(PNG_SHARED)
  add_library(png SHARED ${libpng_sources})
  set(PNG_LIB_TARGETS png)
  set_target_properties(png PROPERTIES OUTPUT_NAME ${PNG_LIB_NAME})
  add_dependencies(png genfiles)
  if(MSVC)
    # msvc does not append 'lib' - do it here to have consistent name
    set_target_properties(png PROPERTIES PREFIX "lib")
    set_target_properties(png PROPERTIES IMPORT_PREFIX "lib")
  endif()
  target_link_libraries(png ${ZLIB_LIBRARY} ${M_LIBRARY})

  if(UNIX AND AWK)
    if(HAVE_LD_VERSION_SCRIPT)
      set_target_properties(png PROPERTIES LINK_FLAGS
        "-Wl,--version-script='${CMAKE_CURRENT_BINARY_DIR}/libpng.vers'")
    elseif(HAVE_SOLARIS_LD_VERSION_SCRIPT)
      set_target_properties(png PROPERTIES LINK_FLAGS
        "-Wl,-M -Wl,'${CMAKE_CURRENT_BINARY_DIR}/libpng.vers'")
    endif()
  endif()
endif()

if(PNG_STATIC)
  # does not work without changing name
  set(PNG_LIB_NAME_STATIC png_static)
  add_library(png_static STATIC ${libpng_sources})
  add_dependencies(png_static genfiles)
  # MSVC doesn't use a different file extension for shared vs. static
  # libs.  We are able to change OUTPUT_NAME to remove the _static
  # for all other platforms.
  if(NOT MSVC)
    set_target_properties(png_static PROPERTIES
      OUTPUT_NAME "${PNG_LIB_NAME}"
      CLEAN_DIRECT_OUTPUT 1)
  else()
    set_target_properties(png_static PROPERTIES
      OUTPUT_NAME "${PNG_LIB_NAME}_static"
      CLEAN_DIRECT_OUTPUT 1)
  endif()
  list(APPEND PNG_LIB_TARGETS png_static)
  if(MSVC)
    # msvc does not append 'lib' - do it here to have consistent name
    set_target_properties(png_static PROPERTIES PREFIX "lib")
  endif()
  target_link_libraries(png_static ${ZLIB_LIBRARY} ${M_LIBRARY})
endif()

if(PNG_FRAMEWORK)
  set(PNG_LIB_NAME_FRAMEWORK png_framework)
  add_library(png_framework SHARED ${libpng_sources})
  add_dependencies(png_framework genfiles)
  list(APPEND PNG_LIB_TARGETS png_framework)
  set_target_properties(png_framework PROPERTIES
    FRAMEWORK TRUE
    FRAMEWORK_VERSION ${PNGLIB_VERSION}
    MACOSX_FRAMEWORK_SHORT_VERSION_STRING ${PNGLIB_MAJOR}.${PNGLIB_MINOR}
    MACOSX_FRAMEWORK_BUNDLE_VERSION ${PNGLIB_VERSION}
    MACOSX_FRAMEWORK_IDENTIFIER org.libpng.libpng
    XCODE_ATTRIBUTE_INSTALL_PATH "@rpath"
    PUBLIC_HEADER "${libpng_public_hdrs}"
    OUTPUT_NAME png)
  target_link_libraries(png_framework ${ZLIB_LIBRARY} ${M_LIBRARY})
endif()

if(NOT PNG_LIB_TARGETS)
  message(SEND_ERROR
    "No library variant selected to build. "
    "Please enable at least one of the following options: "
    " PNG_STATIC, PNG_SHARED, PNG_FRAMEWORK")
endif()

if(PNG_SHARED AND WIN32)
  set_target_properties(png PROPERTIES DEFINE_SYMBOL PNG_BUILD_DLL)
endif()

function(png_add_test)
  set(options)
  set(oneValueArgs NAME COMMAND)
  set(multiValueArgs OPTIONS FILES)
  cmake_parse_arguments(_PAT "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})

  if (NOT _PAT_NAME)
    message(FATAL_ERROR "Invalid arguments.  png_add_test requires name.")
  endif()
  if (NOT _PAT_COMMAND)
    message(FATAL_ERROR "Invalid arguments.  png_add_test requires command.")
  endif()

  set(TEST_OPTIONS "${_PAT_OPTIONS}")
  set(TEST_FILES "${_PAT_FILES}")

  configure_file("${CMAKE_CURRENT_SOURCE_DIR}/scripts/test.cmake.in"
                 "${CMAKE_CURRENT_BINARY_DIR}/tests/${_PAT_NAME}.cmake" @ONLY)
  if(CMAKE_MAJOR_VERSION GREATER 2) # have generator expressions
    add_test(NAME "${_PAT_NAME}"
             COMMAND "${CMAKE_COMMAND}"
             "-DLIBPNG=$<TARGET_FILE:png>"
             "-DTEST_COMMAND=$<TARGET_FILE:${_PAT_COMMAND}>"
             -P "${CMAKE_CURRENT_BINARY_DIR}/tests/${_PAT_NAME}.cmake")
  else() # old 2.x add_test; limited and won't work well on Windows
    # Note LIBPNG is a dummy value as there are no generator expressions
    add_test("${_PAT_NAME}" "${CMAKE_COMMAND}"
             "-DLIBPNG=${CMAKE_CURRENT_BINARY_DIR}/libpng.so"
             "-DTEST_COMMAND=./${_PAT_COMMAND}"
             -P "${CMAKE_CURRENT_BINARY_DIR}/tests/${_PAT_NAME}.cmake")
  endif()
endfunction()

if(PNG_TESTS AND PNG_SHARED)
  # Find test PNG files by globbing, but sort lists to ensure
  # consistency between different filesystems.
  file(GLOB PNGSUITE_PNGS "${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/*.png")
  list(SORT PNGSUITE_PNGS)
  file(GLOB TEST_PNGS "${CMAKE_CURRENT_SOURCE_DIR}/contrib/testpngs/*.png")
  list(SORT TEST_PNGS)

  set(PNGTEST_PNG "${CMAKE_CURRENT_SOURCE_DIR}/pngtest.png")

  add_executable(pngtest ${pngtest_sources})
  target_link_libraries(pngtest png)

  png_add_test(NAME pngtest COMMAND pngtest FILES "${PNGTEST_PNG}")

  add_executable(pngvalid ${pngvalid_sources})
  target_link_libraries(pngvalid png)

  png_add_test(NAME pngvalid-gamma-16-to-8
               COMMAND pngvalid OPTIONS --gamma-16-to-8)
  png_add_test(NAME pngvalid-gamma-alpha-mode
               COMMAND pngvalid OPTIONS --gamma-alpha-mode)
  png_add_test(NAME pngvalid-gamma-background
               COMMAND pngvalid OPTIONS --gamma-background)
  png_add_test(NAME pngvalid-gamma-expand16-alpha-mode
               COMMAND pngvalid OPTIONS --gamma-alpha-mode --expand16)
  png_add_test(NAME pngvalid-gamma-expand16-background
               COMMAND pngvalid OPTIONS --gamma-background --expand16)
  png_add_test(NAME pngvalid-gamma-expand16-transform
               COMMAND pngvalid OPTIONS --gamma-transform --expand16)
  png_add_test(NAME pngvalid-gamma-sbit
               COMMAND pngvalid OPTIONS --gamma-sbit)
  png_add_test(NAME pngvalid-gamma-threshold
               COMMAND pngvalid OPTIONS --gamma-threshold)
  png_add_test(NAME pngvalid-gamma-transform
               COMMAND pngvalid OPTIONS --gamma-transform)
  png_add_test(NAME pngvalid-progressive-interlace-standard
               COMMAND pngvalid OPTIONS --standard --progressive-read --interlace)
  png_add_test(NAME pngvalid-progressive-size
               COMMAND pngvalid OPTIONS --size --progressive-read)
  png_add_test(NAME pngvalid-progressive-standard
               COMMAND pngvalid OPTIONS --standard --progressive-read)
  png_add_test(NAME pngvalid-standard
               COMMAND pngvalid OPTIONS --standard)
  png_add_test(NAME pngvalid-transform
               COMMAND pngvalid OPTIONS --transform)
endif()

# Ensure the CMAKE_LIBRARY_OUTPUT_DIRECTORY is set
IF(NOT CMAKE_LIBRARY_OUTPUT_DIRECTORY)
  SET(CMAKE_LIBRARY_OUTPUT_DIRECTORY "lib")
ENDIF(NOT CMAKE_LIBRARY_OUTPUT_DIRECTORY)

# Set a variable with CMake code which:
# Creates a symlink from src to dest (if possible) or alternatively
# copies if different.
macro(CREATE_SYMLINK SRC_FILE DEST_FILE)
  FILE(REMOVE ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE})
  if(WIN32 AND NOT CYGWIN AND NOT MSYS)
    ADD_CUSTOM_COMMAND(
        OUTPUT ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE}   ${CMAKE_CURRENT_BINARY_DIR}/${DEST_FILE}
        COMMAND ${CMAKE_COMMAND} -E copy_if_different  "${SRC_FILE}" ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE}
        COMMAND ${CMAKE_COMMAND} -E copy_if_different  "${SRC_FILE}" ${CMAKE_CURRENT_BINARY_DIR}/${DEST_FILE}
        DEPENDS ${PNG_LIB_TARGETS}
        )
    ADD_CUSTOM_TARGET(${DEST_FILE}_COPY ALL DEPENDS ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE})
  else(WIN32 AND NOT CYGWIN AND NOT MSYS)
    get_filename_component(LINK_TARGET "${SRC_FILE}" NAME)
    execute_process(COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_LIBRARY_OUTPUT_DIRECTORY})
    execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink "${LINK_TARGET}" ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE} WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
    execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink "${LINK_TARGET}" ${DEST_FILE} WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
  endif(WIN32 AND NOT CYGWIN AND NOT MSYS)
endmacro()

# Create source generation scripts.
configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/genchk.cmake.in
               ${CMAKE_CURRENT_BINARY_DIR}/scripts/genchk.cmake @ONLY)
configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/genout.cmake.in
               ${CMAKE_CURRENT_BINARY_DIR}/scripts/genout.cmake @ONLY)
configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/gensrc.cmake.in
               ${CMAKE_CURRENT_BINARY_DIR}/scripts/gensrc.cmake @ONLY)


# libpng is a library so default to 'lib'
if(NOT DEFINED CMAKE_INSTALL_LIBDIR)
  set(CMAKE_INSTALL_LIBDIR lib)
endif(NOT DEFINED CMAKE_INSTALL_LIBDIR)

# CREATE PKGCONFIG FILES
# we use the same files like ./configure, so we have to set its vars
# Only do this on Windows for Cygwin - the files don't make much sense outside
# a UNIX look alike
if(NOT WIN32 OR CYGWIN OR MINGW)
  set(prefix      ${CMAKE_INSTALL_PREFIX})
  set(exec_prefix ${CMAKE_INSTALL_PREFIX})
  set(libdir      ${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR})
  set(includedir  ${CMAKE_INSTALL_PREFIX}/include)
  set(LIBS        "-lz -lm")
  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/libpng.pc.in
    ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}.pc @ONLY)
  CREATE_SYMLINK(${PNGLIB_NAME}.pc libpng.pc)

  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/libpng-config.in
    ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config @ONLY)
  CREATE_SYMLINK(${PNGLIB_NAME}-config libpng-config)
endif(NOT WIN32 OR CYGWIN OR MINGW)

# SET UP LINKS
if(PNG_SHARED)
  set_target_properties(png PROPERTIES
#   VERSION 15.${PNGLIB_RELEASE}.1.5.28
    VERSION 15.${PNGLIB_RELEASE}.0
    SOVERSION 15
    CLEAN_DIRECT_OUTPUT 1)
endif()

# If CMake > 2.4.x, we set a variable used below to export
# targets to an export file.
# TODO: Use VERSION_GREATER after our cmake_minimum_required >= 2.6.2
if(CMAKE_MAJOR_VERSION GREATER 1 AND CMAKE_MINOR_VERSION GREATER 4)
  set(PNG_EXPORT_RULE EXPORT libpng)
elseif(CMAKE_MAJOR_VERSION GREATER 2) # future proof
  set(PNG_EXPORT_RULE EXPORT libpng)
endif()

# INSTALL
if(NOT SKIP_INSTALL_LIBRARIES AND NOT SKIP_INSTALL_ALL )
  install(TARGETS ${PNG_LIB_TARGETS}
      ${PNG_EXPORT_RULE}
      RUNTIME DESTINATION bin
      LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
      ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
      FRAMEWORK DESTINATION ${CMAKE_INSTALL_LIBDIR})

  if(PNG_SHARED)
    # Create a symlink for libpng.dll.a => libpng15.dll.a on Cygwin
    if(CYGWIN OR MINGW)
       get_target_property(BUILD_TARGET_LOCATION png LOCATION_${CMAKE_BUILD_TYPE})
       CREATE_SYMLINK(${BUILD_TARGET_LOCATION} libpng${CMAKE_IMPORT_LIBRARY_SUFFIX})
       install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_IMPORT_LIBRARY_SUFFIX}
         DESTINATION ${CMAKE_INSTALL_LIBDIR})
    endif(CYGWIN OR MINGW)

    if(NOT WIN32)
      get_target_property(BUILD_TARGET_LOCATION png LOCATION_${CMAKE_BUILD_TYPE})
      CREATE_SYMLINK(${BUILD_TARGET_LOCATION} libpng${CMAKE_SHARED_LIBRARY_SUFFIX})
      install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_SHARED_LIBRARY_SUFFIX}
         DESTINATION ${CMAKE_INSTALL_LIBDIR})
    endif(NOT WIN32)
  endif(PNG_SHARED)

  if(PNG_STATIC)
    if(NOT WIN32 OR CYGWIN OR MINGW)
      get_target_property(BUILD_TARGET_LOCATION png_static LOCATION_${CMAKE_BUILD_TYPE})
      CREATE_SYMLINK(${BUILD_TARGET_LOCATION} libpng${CMAKE_STATIC_LIBRARY_SUFFIX})
      install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_STATIC_LIBRARY_SUFFIX}
         DESTINATION ${CMAKE_INSTALL_LIBDIR})
    endif(NOT WIN32 OR CYGWIN OR MINGW)
 endif()
endif()

if(NOT SKIP_INSTALL_HEADERS AND NOT SKIP_INSTALL_ALL )
  install(FILES ${libpng_public_hdrs}   DESTINATION include)
  install(FILES ${libpng_public_hdrs}   DESTINATION include/${PNGLIB_NAME})
endif()
if(NOT SKIP_INSTALL_EXECUTABLES AND NOT SKIP_INSTALL_ALL )
  if(NOT WIN32 OR CYGWIN OR MINGW)
    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng-config DESTINATION bin)
    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config
            DESTINATION bin)
  endif(NOT WIN32 OR CYGWIN OR MINGW)
endif()

if(NOT SKIP_INSTALL_PROGRAMS AND NOT SKIP_INSTALL_ALL )
  install(TARGETS ${PNG_BIN_TARGETS}
      RUNTIME DESTINATION bin)
endif()

if(NOT SKIP_INSTALL_FILES AND NOT SKIP_INSTALL_ALL )
  # Install man pages
  if(NOT PNG_MAN_DIR)
    set(PNG_MAN_DIR "share/man")
  endif()
  install(FILES libpng.3 libpngpf.3      DESTINATION ${PNG_MAN_DIR}/man3)
  install(FILES png.5                    DESTINATION ${PNG_MAN_DIR}/man5)
  # Install pkg-config files
  if(NOT WIN32 OR CYGWIN OR MINGW)
    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng.pc
            DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng-config
            DESTINATION bin)
    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}.pc
            DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config
            DESTINATION bin)
  endif(NOT WIN32 OR CYGWIN OR MINGW)
endif()

# On versions of CMake that support it, create an export file CMake
# users can include() to import our targets
if(PNG_EXPORT_RULE AND NOT SKIP_INSTALL_EXPORT AND NOT SKIP_INSTALL_ALL )
  install(EXPORT libpng DESTINATION lib/libpng FILE lib${PNG_LIB_NAME}.cmake)
endif()

# what's with libpng-manual.txt and all the extra files?

# UNINSTALL
# do we need this?

# DIST
# do we need this?

# to create msvc import lib for mingw compiled shared lib
# pexports libpng.dll > libpng.def
# lib /def:libpng.def /machine:x86