Ubuntu20.04 配置Opencv+VScode+cmake

一：Opencv安装

参考该篇博文安装即可，有的地方要连外网。

下面是总结 ，直接copy即可：

#确保Ubuntu上有安装过程中使用到的一些工具，如果没有，请输入以下指令安装
sudo apt install -y g++
sudo apt install -y cmake
sudo apt install -y make
sudo apt install -y wget unzip

#输入以下指令安装OpenCV依赖的基本库
sudo apt-get install build-essential libgtk2.0-dev libgtk-3-dev libavcodec-dev libavformat-dev libjpeg-dev libswscale-dev libtiff5-dev

#安装4.5.0版本
wget -O opencv.zip https://github.com/opencv/opencv/archive/4.5.0.zip
#或安装opencv最新版本
wget -O opencv.zip https://github.com/opencv/opencv/archive/master.zip

#其他版本可从opencv官网下载
#下载完后解压缩并重命名为opencv（源码包大小大概90M）
unzip opencv.zip
mv opencv4.5.0 opencv

--------------------------------------------------------------------------------------------
配置和编译OpenCV
---------------------------------------------------------------------------------------------

#进入到下载好的opencv目录中，新建目录build并进入build目录
cd opencv
mkdir build
cd build

#使用cmake配置opencv
$ cmake -D CMAKE_BUILD_TYPE=Release -D OPENCV_GENERATE_PKGCONFIG=YES ..

#使用make编译
make -j4

#使用make安装
sudo make install

// 默认安装路径为：
// /usr/local/bin - executable files
// /usr/local/lib - libraries (.so)
// /usr/local/cmake/opencv4 - cmake package
// /usr/local/include/opencv4 - headers
// /usr/local/share/opencv4 - other files (e.g. trained cascades in XML format)

--------------------------------------------------------------------------------------------
环境配置
---------------------------------------------------------------------------------------------

#配置pkg-config环境
#opencv4.pc文件的默认路径为/usr/local/lib/pkgconfig/opencv4.pc，如果此目录下没有，可以使用以下命令搜索：
find / -iname opencv4.pc

#将路径加入到PKG_CONFIG_PATH，打开是个空文件
sudo vim /etc/profile.d/pkgconfig.sh

#在文件后面加入下面一行：
export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig:$PKG_CONFIG_PATH

#保存并退出后激活，激活后不会退出可以关闭终端
source /etc/profile

#验证是否成功
$ pkg-config --libs opencv4
-L/usr/local/lib -lopencv_dnn -lopencv_highgui -lopencv_ml -lopencv_objdetect -lopencv_photo 
-lopencv_stitching -lopencv_video -lopencv_calib3d -lopencv_features2d -lopencv_flann 
-lopencv_videoio -lopencv_imgcodecs -lopencv_imgproc -lopencv_core

#配置动态库环境，打开文件（可能为空文件）
sudo vim /etc/ld.so.conf.d/opencv4.conf

#在该文件末尾加上OpenCV的lib路径
/usr/local/lib

#使配置的路径生效
sudo ldconfig

#测试安装成功与否，输出版本信息
pkg-config --modversion opencv4

--------------------------------------------------------------------------------------------
卸载 OpenCV4(通过源码编译安装)
---------------------------------------------------------------------------------------------

#找到源码路径，在终端中进入到build目录，依次执行
sudo make uninstall
cd ..
sudo rm -r build

#在/usr/local下搜索opencv4
sudo find ./ -name opencv4*

#将找到的opencv相关项删除即可，大概删除以下项
sudo rm -r /usr/local/include/opencv4
sudo rm -r /usr/local/lib/pkgconfig/opencv4.pc
sudo rm -r /usr/local/lib/cmake/opencv4
sudo rm -r /usr/local/share/licenses/opencv4
sudo rm -r /usr/local/share/opencv4

二：环境设置

c_cpp_properties.json，是整个C++的环境配置，配置如下：

{
    "configurations": [
        {
            "name": "Linux",
            "includePath": [
                "${workspaceFolder}/**",
                "/usr/include/x86_64-linux-gnu/sys",
                "/usr/local/lib/**",
                "/usr/local/include/opencv4/**"
            ],
            "defines": [],
            "compilerPath": "/usr/bin/gcc",
            "cStandard": "gnu17",
            "cppStandard": "gnu++14",
            "intelliSenseMode": "linux-gcc-x64"
        }
    ],
    "version": 4
}

launch.json是生成和调试活动文件的配置，先根据task.json的配置生成文件，配置如下:

{
    "configurations": [
        {
            "name": "C/C++: g++ 生成和调试活动文件",
            "type": "cppdbg",
            "request": "launch",
            "program": "${fileDirname}/${fileBasenameNoExtension}",
            "args": [
                "`pkg-config",
                "--libs",
                "--cflags",
                "opencv4`"
            ],
            "stopAtEntry": false,
            "cwd": "${fileDirname}",
            "environment": [],
            "externalConsole": false,
            "MIMode": "gdb",
            "setupCommands": [
                {
                    "description": "为 gdb 启用整齐打印",
                    "text": "-enable-pretty-printing",
                    "ignoreFailures": true
                },
                {
                    "description": "将反汇编风格设置为 Intel",
                    "text": "-gdb-set disassembly-flavor intel",
                    "ignoreFailures": true
                }
            ],
            "preLaunchTask": "C/C++: g++ 生成活动文件",
            "miDebuggerPath": "/usr/bin/gdb",
            "miDebuggerArgs": "-q -ex quit; wait() { fg >/dev/null; }; /usr/bin/gdb -q --interpreter=mi"
        },
    ],
    "version": "2.0.0"
}

tasks.json配置生成活动文件的方式，配置如下:

{
    "tasks": [
        {
            "type": "cppbuild",
            "label": "C/C++: g++ 生成活动文件",
            "command": "/usr/bin/g++",
            "args": [
                "-fdiagnostics-color=always",
                "-g",
                "${file}",
                "-o",
                "${fileDirname}/${fileBasenameNoExtension}",
                "`pkg-config",
                "--libs",
                "--cflags",
                "opencv4`"
            ],
            "options": {
                "cwd": "${fileDirname}"
            },
            "problemMatcher": [
                "$gcc"
            ],
            "group": "build",
            "detail": "调试器生成的任务。"
        },
    ],
    "version": "2.0.0"
}

注意在点击运行时，选择的配置文件需要和这三个json文件一致，比如是C/C++: g++ 生成和调试活动文件就不要选cpp生成和调试，不然会自动生成cpp的配置文件，并且运行它，而不是你设置好的g++配置文件。

如果之前已经选错了，点击箭头也没有重新选择配置方式的提醒，那就修改json文件，实在不行重新创建一个launch.json即可。