Commit 9b08c623 authored by Sam Thursfield's avatar Sam Thursfield Committed by Brad King

FindPNG: Create an imported PNG::PNG target (#15911)

Imported targets are now the recommended way of dealing with external
library dependencies.  Add one for FindPNG and update documentation
accordingly.  Also add a test case activated by CMake_TEST_FindPNG.
parent c13ed964
FindPNG-imported-targets
------------------------
* The :module:`FindPNG` module now provides imported targets.
......@@ -2,13 +2,20 @@
# FindPNG
# -------
#
# Find the native PNG includes and library
# Find libpng, the official reference library for the PNG image format.
#
# Imported targets
# ^^^^^^^^^^^^^^^^
#
# This module defines the following :prop_tgt:`IMPORTED` target:
#
# This module searches libpng, the library for working with PNG images.
# ``PNG::PNG``
# The libpng library, if found.
#
# It defines the following variables
# Result variables
# ^^^^^^^^^^^^^^^^
#
# This module will set the following variables in your project:
#
# ``PNG_INCLUDE_DIRS``
# where to find png.h, etc.
......@@ -22,19 +29,22 @@
# ``PNG_VERSION_STRING``
# the version of the PNG library found (since CMake 2.8.8)
#
# Also defined, but not for general use are
# Obsolete variables
# ^^^^^^^^^^^^^^^^^^
#
# The following variables may also be set, for backwards compatibility:
#
# ``PNG_LIBRARY``
# where to find the PNG library.
#
# For backward compatiblity the variable PNG_INCLUDE_DIR is also set.
# It has the same value as PNG_INCLUDE_DIRS.
# ``PNG_INCLUDE_DIR``
# where to find the PNG headers (same as PNG_INCLUDE_DIRS)
#
# Since PNG depends on the ZLib compression library, none of the above
# will be defined unless ZLib can be found.
#=============================================================================
# Copyright 2002-2009 Kitware, Inc.
# Copyright 2016 Raumfeld
#
# Distributed under the OSI-approved BSD License (the "License");
# see accompanying file Copyright.txt for details.
......@@ -105,6 +115,32 @@ if(ZLIB_FOUND)
endif()
endif ()
if(NOT TARGET PNG::PNG)
add_library(PNG::PNG UNKNOWN IMPORTED)
set_target_properties(PNG::PNG PROPERTIES
INTERFACE_COMPILE_DEFINITIONS "${PNG_DEFINITIONS}"
INTERFACE_INCLUDE_DIRECTORIES "${PNG_INCLUDE_DIRS}"
INTERFACE_LINK_LIBRARIES ZLIB::ZLIB)
if(EXISTS "${PNG_LIBRARY}")
set_target_properties(PNG::PNG PROPERTIES
IMPORTED_LINK_INTERFACE_LANGUAGES "C"
IMPORTED_LOCATION "${PNG_LIBRARY}")
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()
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()
endif()
endif ()
if (PNG_PNG_INCLUDE_DIR AND EXISTS "${PNG_PNG_INCLUDE_DIR}/png.h")
......
......@@ -1375,6 +1375,10 @@ ${CMake_BINARY_DIR}/bin/cmake -DDIR=dev -P ${CMake_SOURCE_DIR}/Utilities/Release
add_subdirectory(FindOpenSSL)
endif()
if(CMake_TEST_FindPNG)
add_subdirectory(FindPNG)
endif()
if(CMake_TEST_FindTIFF)
add_subdirectory(FindTIFF)
endif()
......
add_test(NAME FindPNG.Test COMMAND
${CMAKE_CTEST_COMMAND} -C $<CONFIGURATION>
--build-and-test
"${CMake_SOURCE_DIR}/Tests/FindPNG/Test"
"${CMake_BINARY_DIR}/Tests/FindPNG/Test"
${build_generator_args}
--build-project TestFindPNG
--build-options ${build_options}
--test-command ${CMAKE_CTEST_COMMAND} -V -C $<CONFIGURATION>
)
cmake_minimum_required(VERSION 3.4)
project(TestFindPNG C)
include(CTest)
find_package(PNG REQUIRED)
add_definitions(-DCMAKE_EXPECTED_PNG_VERSION="${PNG_VERSION_STRING}")
add_executable(test_tgt main.c)
target_link_libraries(test_tgt PNG::PNG)
add_test(NAME test_tgt COMMAND test_tgt)
add_executable(test_var main.c)
target_include_directories(test_var PRIVATE ${PNG_INCLUDE_DIRS})
target_link_libraries(test_var PRIVATE ${PNG_LIBRARIES})
add_test(NAME test_var COMMAND test_var)
#include <assert.h>
#include <string.h>
#include <png.h>
int main()
{
png_uint_32 png_version;
char png_version_string[16];
png_version = png_access_version_number ();
snprintf (png_version_string, 16, "%i.%i.%i",
png_version / 10000,
(png_version % 10000) / 100,
png_version % 100);
assert (strcmp(png_version_string, CMAKE_EXPECTED_PNG_VERSION) == 0);
return 0;
}
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