[cmake-developers] [PATCH] FindPNG: Create an imported PNG::PNG target
Sam Thursfield
sam.thursfield at codethink.co.uk
Tue Jan 19 12:43:05 EST 2016
Imported targets are now the recommended way of dealing with external
library dependencies.
The documentation for FindPNG is rewritten slightly.
This commit also adds a test case, you can run it like this:
cmake ... -DCMake_TEST_FindPNG=ON
ctest -R FindPNG --output-on-failure
The testcase requires the libpng library and headers to be installed.
This change is based on the equivalent changes to FindTIFF, found in
commit ebaca6290d2c0be7dec22452389632949a700d28.
https://cmake.org/Bug/view.php?id=15911
---
Help/release/dev/FindPNG-imported-targets.rst | 4 +++
Modules/FindPNG.cmake | 50 +++++++++++++++++++++++----
Tests/CMakeLists.txt | 4 +++
Tests/FindPNG/CMakeLists.txt | 10 ++++++
Tests/FindPNG/Test/CMakeLists.txt | 16 +++++++++
Tests/FindPNG/Test/main.c | 20 +++++++++++
6 files changed, 97 insertions(+), 7 deletions(-)
create mode 100644 Help/release/dev/FindPNG-imported-targets.rst
create mode 100644 Tests/FindPNG/CMakeLists.txt
create mode 100644 Tests/FindPNG/Test/CMakeLists.txt
create mode 100644 Tests/FindPNG/Test/main.c
diff --git a/Help/release/dev/FindPNG-imported-targets.rst b/Help/release/dev/FindPNG-imported-targets.rst
new file mode 100644
index 0000000..e0d0ab1
--- /dev/null
+++ b/Help/release/dev/FindPNG-imported-targets.rst
@@ -0,0 +1,4 @@
+FindPNG-imported-targets
+------------------------
+
+* The :module:`FindPNG` module now provides imported targets.
diff --git a/Modules/FindPNG.cmake b/Modules/FindPNG.cmake
index 7cf3f22..d1d5e67 100644
--- a/Modules/FindPNG.cmake
+++ b/Modules/FindPNG.cmake
@@ -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_LIBRARIES "${PNG_LIBRARIES}")
+ if(EXISTS "${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")
diff --git a/Tests/CMakeLists.txt b/Tests/CMakeLists.txt
index 043b757..3cca77b 100644
--- a/Tests/CMakeLists.txt
+++ b/Tests/CMakeLists.txt
@@ -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()
diff --git a/Tests/FindPNG/CMakeLists.txt b/Tests/FindPNG/CMakeLists.txt
new file mode 100644
index 0000000..c665b67
--- /dev/null
+++ b/Tests/FindPNG/CMakeLists.txt
@@ -0,0 +1,10 @@
+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 $<CONFIGURATION>
+ )
diff --git a/Tests/FindPNG/Test/CMakeLists.txt b/Tests/FindPNG/Test/CMakeLists.txt
new file mode 100644
index 0000000..ad50011
--- /dev/null
+++ b/Tests/FindPNG/Test/CMakeLists.txt
@@ -0,0 +1,16 @@
+cmake_minimum_required(VERSION 3.4)
+project(TestFindPNG C)
+include(CTest)
+
+find_package(PNG REQUIRED)
+
+add_definitions(-DCMAKE_EXPECTED_PNG_VERSION="${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)
diff --git a/Tests/FindPNG/Test/main.c b/Tests/FindPNG/Test/main.c
new file mode 100644
index 0000000..27e1478
--- /dev/null
+++ b/Tests/FindPNG/Test/main.c
@@ -0,0 +1,20 @@
+#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;
+}
--
2.4.3
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