开罗图书馆和Cmake

Question

我是c ++和cmake的新手。 我通过端口安装了这里写的cairo库。 现在我想将cairo包含在我的项目中。 我写的CMakeLists.txt命令，如图所示这里 。

cmake_minimum_required(VERSION 3.6)
project(HelloOpenGL)

set(CMAKE_CXX_STANDARD 11)

set(SOURCE_FILES main.cpp)
add_executable(HelloOpenGL ${SOURCE_FILES})

#find_package(ImageMagick COMPONENTS Magick++)
#include_directories(${ImageMagick_INCLUDE_DIRS})
#target_link_libraries(HelloOpenGL ${ImageMagick_LIBRARIES})

find_package(Cairo)
include_directories(${Cairo_INCLUDE_DIRS})
target_link_libraries(HelloOpenGL ${Cairo_LIBRARIES})

if(CAIRO_FOUND)
    message("Cairo found")
    else()
    message("Cairo not found")
    endif()

但它不起作用，我得到这个输出 -

CMake Warning at CMakeLists.txt:16 (find_package):
  By not providing "FindCairo.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "Cairo", but
  CMake did not find one.

  Could not find a package configuration file provided by "Cairo" with any of
  the following names:

    CairoConfig.cmake
    cairo-config.cmake

  Add the installation prefix of "Cairo" to CMAKE_PREFIX_PATH or set
  "Cairo_DIR" to a directory containing one of the above files.  If "Cairo"
  provides a separate development package or SDK, be sure it has been
  installed.

请帮我正确地包括cairo

Answer 1

问题是你的CMake版本没有（顺便说一下，甚至连CMake的最新开发版都没有... https://gitlab.kitware.com/cmake/cmake/tree/master/Modules ）您需要运行命令find_package(Cairo)的文件FindCairo.cmake ，并且您没有在包中包含此文件。
解决方案是从Web获取FindCairo.cmake文件，在项目的根目录中创建一个cmake目录，并在CMakeLists.txt中添加额外的行

set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_CURRENT_SOURCE_DIR}/cmake")

所以你的CMakeLists.txt片段看起来像：

cmake_minimum_required(VERSION 3.6)
project(HelloOpenGL)
set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
set(CMAKE_CXX_STANDARD 11)

set(SOURCE_FILES main.cpp)
add_executable(HelloOpenGL ${SOURCE_FILES})

#find_package(ImageMagick COMPONENTS Magick++)
#include_directories(${ImageMagick_INCLUDE_DIRS})
#target_link_libraries(HelloOpenGL ${ImageMagick_LIBRARIES})

find_package(Cairo)
include_directories(${Cairo_INCLUDE_DIRS})
target_link_libraries(HelloOpenGL ${Cairo_LIBRARIES})

如果您不使用现有的FindCairo.cmake （例如您安装的Cairo可能包含一个此类文件），则必须编写一个或找到包含该包的替代方法。