opencv:windows下调用cvShowImage等窗口显示函数报错：The function is not implement

自己在windows下用cmake成功编译了opencv 2.4.13.2，但在实际调用cvShowImage函数时报错了：

OpenCV Error: Unspecified error (The function is not implemented. Rebuild the library with Windows, GTK+ 2.x or Carbon support. If you are on Ubuntu or Debian, install libgtk2.0-dev and pkg-config, then re-run cmake or configure script) in cvNamedWindow, file D:caffe-staticsourceopencv-2.4.13.2moduleshighguisrcwindow.cpp, line 501 terminate called after throwing an instance of ‘cv::Exception’

这个错误提示的意思就是cvShowImage这个函数没有被实现。查看了opencv-2.4.13.2moduleshighguisrcwindow.cpp源码，才明白这个文件只是没有函数实现的虚代码。windows下的真正实现代码是同文件夹下的windows_w32.cpp。应该是编译开关问题造成没有编译windows_w32.cpp。于是在opencv-2.4.13.2moduleshighguiCMakeLists.txt中找到如下代码，可以看到HAVE_WIN32UI用于控制是否编译windows_w32.cpp：

elseif(HAVE_WIN32UI)
  list(APPEND highgui_srcs src/window_w32.cpp)
elseif(HAVE_GTK)
  list(APPEND highgui_srcs src/window_gtk.cpp)
elseif(HAVE_CARBON)
  list(APPEND highgui_srcs src/window_carbon.cpp)
  list(APPEND HIGHGUI_LIBRARIES "-framework Carbon" "-framework QuickTime")
elseif(HAVE_COCOA)
  list(APPEND highgui_srcs src/window_cocoa.mm)
  list(APPEND HIGHGUI_LIBRARIES "-framework Cocoa")
endif()

进一步在opencv-2.4.13.2CMakeLists.txt下找到了控制HAVE_WIN32UI的开关选项WITH_WIN32UI，如下：

else()
  if(DEFINED WITH_QT)
    status("    QT:" NO)
  endif()
  if(DEFINED WITH_WIN32UI)
    status("    Win32 UI:" HAVE_WIN32UI THEN YES ELSE NO)
  else()
    if(APPLE)
      if(WITH_CARBON)
        status("    Carbon:" YES)
      else()
        status("    Cocoa:"  YES)
      endif()
    else()
      status("    GTK+ 2.x:" HAVE_GTK      THEN "YES (ver ${ALIASOF_gtk+-2.0_VERSION})"     ELSE NO)
      status("    GThread :" HAVE_GTHREAD  THEN "YES (ver ${ALIASOF_gthread-2.0_VERSION})"  ELSE NO)
      status("    GtkGlExt:" HAVE_GTKGLEXT THEN "YES (ver ${ALIASOF_gtkglext-1.0_VERSION})" ELSE NO)
    endif()
  endif()
endif()

至此找到原因：编译opencv的时候设置了WITH_WIN32UI=off导致cmake没有编译windows_w32.cpp最终导致运行时调用cvShowImage出错。解决办法也很简单，在cmake生成Makefile的命令行参数中添加-DWITH_WIN32UI=on指定编译加入UI函数支持。以下是我编译opencv的完整命令行参数（注意最后一行）:

cmake .. -G "MinGW Makefiles" 
    -DCMAKE_BUILD_TYPE:STRING=release 
    -DCMAKE_C_FLAGS="-m64  " 
    -DCMAKE_CXX_FLAGS="-m64  " 
    -DCMAKE_EXE_LINKER_FLAGS="-static -static-libstdc++ -static-libgcc  " 
    -DCMAKE_INSTALL_PREFIX="D:caffe-staticreleaseopencv_windows_gcc520_x86_64" 
    -DBUILD_DOCS=off 
    -DBUILD_SHARED_LIBS=off 
    -DBUILD_PACKAGE=on 
    -DBUILD_PERF_TESTS=off 
    -DBUILD_FAT_JAVA_LIB=off 
    -DBUILD_TESTS=off 
    -DBUILD_TIFF=on 
    -DBUILD_JASPER=on 
    -DBUILD_JPEG=on 
    -DBUILD_OPENEXR=on 
    -DBUILD_PNG=on 
    -DBUILD_ZLIB=on 
    -DBUILD_opencv_apps=off 
    -DBUILD_opencv_calib3d=off 
    -DBUILD_opencv_contrib=off 
    -DBUILD_opencv_features2d=off 
    -DBUILD_opencv_flann=off 
    -DBUILD_opencv_gpu=off 
    -DBUILD_opencv_java=off 
    -DBUILD_opencv_legacy=off 
    -DBUILD_opencv_ml=off 
    -DBUILD_opencv_nonfree=off 
    -DBUILD_opencv_objdetect=off 
    -DBUILD_opencv_ocl=off 
    -DBUILD_opencv_photo=off 
    -DBUILD_opencv_python=off 
    -DBUILD_opencv_stitching=off 
    -DBUILD_opencv_superres=off 
    -DBUILD_opencv_ts=off 
    -DBUILD_opencv_video=off 
    -DBUILD_opencv_videostab=off 
    -DBUILD_opencv_world=off 
    -DBUILD_opencv_lengcy=off 
    -DWITH_DSHOW=off 
    -DWITH_JASPER=on 
    -DWITH_JPEG=on 
    -DWITH_1394=off 
    -DWITH_OPENEXR=on 
    -DWITH_PNG=on 
    -DWITH_TIFF=on 
    -DWITH_1394=off 
    -DWITH_EIGEN=off 
    -DWITH_FFMPEG=off 
    -DWITH_GIGEAPI=off 
    -DWITH_GSTREAMER_0_10=off 
    -DWITH_PVAPI=off -DWITH_CUDA=off 
    -DWITH_CUFFT=off 
    -DWITH_OPENCL=off 
    -DWITH_OPENCLAMDBLAS=off 
    -DWITH_OPENCLAMDFFT=off 
    -DWITH_QT=off 
    -DWITH_VFW=off 
    -DWITH_VTK=off 
    -DWITH_XIMEA=off 
    -DWITH_WIN32UI=on