qt导入opencv依赖

qt这个东西上手快，但是依赖库的设置挺费劲。

这里以opencv为例，介绍qt的依赖设置。opencv的下载方式：
https://blog.csdn.net/weixin_44684139/article/details/104837210

主要更改的是.pro文件：

1. PATH部分

PATH部分包含INCLUDEPATH和DEPENDPATH，比如：

INCLUDEPATH +=/usr/local/opencv3/include
DEPENDPATH +=/usr/local/opencv3/lib

INCLUDEPATH设定路径后，在工程中include进来的.h文件就可以在指定路径下被找到。

DEPENDPATH设定路径后，共享库即可被寻找到。

2. 共享库部分

共享库部分使用LIBS+=

LIBS +=     /usr/local/opencv3/lib/libopencv_calib3d.so\
    /usr/local/opencv3/lib/libopencv_calib3d.so.3.2\
    /usr/local/opencv3/lib/libopencv_calib3d.so.3.2.0\
    /usr/local/opencv3/lib/libopencv_core.so\
    /usr/local/opencv3/lib/libopencv_core.so.3.2\
    /usr/local/opencv3/lib/libopencv_core.so.3.2.0\
    /usr/local/opencv3/lib/libopencv_features2d.so\
    /usr/local/opencv3/lib/libopencv_features2d.so.3.2\
    /usr/local/opencv3/lib/libopencv_features2d.so.3.2.0\
    /usr/local/opencv3/lib/libopencv_flann.so\
    /usr/local/opencv3/lib/libopencv_flann.so.3.2\
    /usr/local/opencv3/lib/libopencv_flann.so.3.2.0\
    /usr/local/opencv3/lib/libopencv_highgui.so\
    /usr/local/opencv3/lib/libopencv_highgui.so.3.2\
    /usr/local/opencv3/lib/libopencv_highgui.so.3.2.0\
    /usr/local/opencv3/lib/libopencv_imgcodecs.so\
    /usr/local/opencv3/lib/libopencv_imgcodecs.so.3.2\
    /usr/local/opencv3/lib/libopencv_imgcodecs.so.3.2.0\
    /usr/local/opencv3/lib/libopencv_imgproc.so\
    /usr/local/opencv3/lib/libopencv_imgproc.so.3.2\
    /usr/local/opencv3/lib/libopencv_imgproc.so.3.2.0\
    /usr/local/opencv3/lib/libopencv_ml.so\
    /usr/local/opencv3/lib/libopencv_ml.so.3.2\
    /usr/local/opencv3/lib/libopencv_ml.so.3.2.0\
    /usr/local/opencv3/lib/libopencv_objdetect.so\
    /usr/local/opencv3/lib/libopencv_objdetect.so.3.2\
    /usr/local/opencv3/lib/libopencv_objdetect.so.3.2.0\
    /usr/local/opencv3/lib/libopencv_photo.so\
    /usr/local/opencv3/lib/libopencv_photo.so.3.2\
    /usr/local/opencv3/lib/libopencv_photo.so.3.2.0\
    /usr/local/opencv3/lib/libopencv_shape.so\
    /usr/local/opencv3/lib/libopencv_shape.so.3.2\
    /usr/local/opencv3/lib/libopencv_shape.so.3.2.0\
    /usr/local/opencv3/lib/libopencv_stitching.so\
    /usr/local/opencv3/lib/libopencv_stitching.so.3.2\
    /usr/local/opencv3/lib/libopencv_stitching.so.3.2.0\
    /usr/local/opencv3/lib/libopencv_superres.so\
    /usr/local/opencv3/lib/libopencv_superres.so.3.2\
    /usr/local/opencv3/lib/libopencv_superres.so.3.2.0\
    /usr/local/opencv3/lib/libopencv_videoio.so\
    /usr/local/opencv3/lib/libopencv_videoio.so.3.2\
    /usr/local/opencv3/lib/libopencv_videoio.so.3.2.0\
    /usr/local/opencv3/lib/libopencv_video.so\
    /usr/local/opencv3/lib/libopencv_video.so.3.2\
    /usr/local/opencv3/lib/libopencv_video.so.3.2.0\
    /usr/local/opencv3/lib/libopencv_videostab.so\
    /usr/local/opencv3/lib/libopencv_videostab.so.3.2\
    /usr/local/opencv3/lib/libopencv_videostab.so.3.2.0\
    /usr/local/opencv3/lib/libopencv_viz.so\
    /usr/local/opencv3/lib/libopencv_viz.so.3.2\
    /usr/local/opencv3/lib/libopencv_viz.so.3.2.0\

可以使用ls命令列出所有全路径，方便加入：

 ~$ cd /usr/local/opencv3/lib/
 lib$ ls -1 |awk '{print i$0}' i=`pwd`'/'
/usr/local/opencv3/lib/libopencv_calib3d.so
/usr/local/opencv3/lib/libopencv_calib3d.so.3.2
/usr/local/opencv3/lib/libopencv_calib3d.so.3.2.0
/usr/local/opencv3/lib/libopencv_core.so
/usr/local/opencv3/lib/libopencv_core.so.3.2
/usr/local/opencv3/lib/libopencv_core.so.3.2.0
/usr/local/opencv3/lib/libopencv_features2d.so
/usr/local/opencv3/lib/libopencv_features2d.so.3.2
/usr/local/opencv3/lib/libopencv_features2d.so.3.2.0
/usr/local/opencv3/lib/libopencv_flann.so
/usr/local/opencv3/lib/libopencv_flann.so.3.2
/usr/local/opencv3/lib/libopencv_flann.so.3.2.0
/usr/local/opencv3/lib/libopencv_highgui.so
/usr/local/opencv3/lib/libopencv_highgui.so.3.2
/usr/local/opencv3/lib/libopencv_highgui.so.3.2.0
/usr/local/opencv3/lib/libopencv_imgcodecs.so
/usr/local/opencv3/lib/libopencv_imgcodecs.so.3.2
/usr/local/opencv3/lib/libopencv_imgcodecs.so.3.2.0
/usr/local/opencv3/lib/libopencv_imgproc.so
/usr/local/opencv3/lib/libopencv_imgproc.so.3.2
/usr/local/opencv3/lib/libopencv_imgproc.so.3.2.0
/usr/local/opencv3/lib/libopencv_ml.so
/usr/local/opencv3/lib/libopencv_ml.so.3.2
/usr/local/opencv3/lib/libopencv_ml.so.3.2.0
/usr/local/opencv3/lib/libopencv_objdetect.so
/usr/local/opencv3/lib/libopencv_objdetect.so.3.2
/usr/local/opencv3/lib/libopencv_objdetect.so.3.2.0
/usr/local/opencv3/lib/libopencv_photo.so
/usr/local/opencv3/lib/libopencv_photo.so.3.2
/usr/local/opencv3/lib/libopencv_photo.so.3.2.0
/usr/local/opencv3/lib/libopencv_shape.so
/usr/local/opencv3/lib/libopencv_shape.so.3.2
/usr/local/opencv3/lib/libopencv_shape.so.3.2.0
/usr/local/opencv3/lib/libopencv_stitching.so
/usr/local/opencv3/lib/libopencv_stitching.so.3.2
/usr/local/opencv3/lib/libopencv_stitching.so.3.2.0
/usr/local/opencv3/lib/libopencv_superres.so
/usr/local/opencv3/lib/libopencv_superres.so.3.2
/usr/local/opencv3/lib/libopencv_superres.so.3.2.0
/usr/local/opencv3/lib/libopencv_videoio.so
/usr/local/opencv3/lib/libopencv_videoio.so.3.2
/usr/local/opencv3/lib/libopencv_videoio.so.3.2.0
/usr/local/opencv3/lib/libopencv_video.so
/usr/local/opencv3/lib/libopencv_video.so.3.2
/usr/local/opencv3/lib/libopencv_video.so.3.2.0
/usr/local/opencv3/lib/libopencv_videostab.so
/usr/local/opencv3/lib/libopencv_videostab.so.3.2
/usr/local/opencv3/lib/libopencv_videostab.so.3.2.0
/usr/local/opencv3/lib/libopencv_viz.so
/usr/local/opencv3/lib/libopencv_viz.so.3.2
/usr/local/opencv3/lib/libopencv_viz.so.3.2.0
/usr/local/opencv3/lib/pkgconfig
/usr/local/opencv3/lib/python2.7

如果依赖库或者路径设置不完全，一定会报一个迷茫的错误：

error: collect2: error: ld returned 1 exit status