Ubuntu20.04，在Vscode下配置C/C++和Opencv

參考文章 Ubuntu 18.04系統下的環境配置vscode&&opencv&&c++

Opencv的安裝

1.准備工作

ubuntu20.04
cmake>=3.10.2
unzip
mlocate包

更新包

sudo apt update
sudo apt upgrade

簡單安裝cmake

sudo apt install cmake

此安裝方式安裝的cmake可能不是最新的
查看cmake版本

cmake -version

安裝mlocate

sudo apt-get install mlocate

2.編譯

安裝依賴

sudo apt install openssl libssl-dev mingetty zip unzip git curl vim gcc g++ -y
sudo apt install socat zsh curl git vim make cmake -y
sudo apt install autojump -y
sudo apt-get install -y libtiff5-dev libeigen3-dev
sudo apt install -y git gcc g++ make cmake libgtk2.0-dev libgoogle-glog-dev
sudo apt install -y libtesseract-dev libgtkglext1 libgtkglext1-dev ffmpeg
sudo apt install -y libv4l-0 libv4l-dev
sudo apt install -y liblapacke-dev libopenblas-dev libgtk-3-dev libgstreamer-plugins-base1.0-dev
sudo apt install -y libgstreamer1.0-dev libavresample-dev libgphoto2-dev libdc1394-22-dev
sudo apt-get install -y build-essential make cmake cmake-curses-gui git g++ pkg-config curl
sudo apt-get install -y libavcodec-dev libavformat-dev libavutil-dev libswscale-dev libeigen3-dev libglew-dev libgtk2.0-dev
sudo apt-get install -y libtbb2 libtbb-dev v4l-utils qv4l2 v4l2ucp
sudo apt-get install -y libdc1394-22-dev libxine2-dev libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev
sudo apt-get install -y libjpeg8-dev libjpeg-turbo8-dev libtiff-dev libpng-dev
sudo apt-get install -y libxvidcore-dev libx264-dev libgtk-3-dev
sudo apt-get install -y libatlas-base-dev libopenblas-dev liblapack-dev liblapacke-dev gfortran
sudo apt-get install -y qt5-default
sudo apt-get install -y python3-dev python3-testresources
sudo apt-get install -y libcanberra-gtk-module

下載源代碼

選擇合適的opencv版本，contrib庫版本需與opencv版本相同，以目前使用的3.4.7為例，下載zip壓縮包
opencv3.4.7
OpenCV-Contrib
使用shell將壓縮包下載到文件夾內，需要將[version_id]改為需要下載的版本號

cd ~
wget -O opencv.zip https://github.com/opencv/opencv/archive/[version_id].zip
wget -O opencv_contrib.zip https://github.com/opencv/opencv_contrib/archive/[version_id].zip
unzip opencv.zip
unzip opencv_contrib.zip
mv opencv-[version_id] opencv
mv opencv_contrib-[version_id] opencv_contrib

比如我下載的是3.4.7版本，那么

cd ~
wget -O opencv.zip https://github.com/opencv/opencv/archive/3.4.7.zip
wget -O opencv_contrib.zip https://github.com/opencv/opencv_contrib/archive/3.4.7.zip
unzip opencv.zip
unzip opencv_contrib.zip
mv opencv-[version_id] opencv
mv opencv_contrib-[version_id] opencv_contrib

配置cmake並編譯OpenCV

cd ~/opencv
mkdir build
cd build

Cmake編譯命令

-D OPENCV_EXTRA_MODULES_PATH=../../opencv_contrib/modules \此處路徑必須填寫正確，否則編譯測試通過后代碼仍然可能編譯報錯，缺少xxx文件

cmake -D CMAKE_BUILD_TYPE=RELEASE \
-D CMAKE_INSTALL_PREFIX=/usr/local \
-D ENABLE_NEON=OFF \
-D ENABLE_FAST_MATH=ON \
-D WITH_GSTREAMER=ON \
-D WITH_LIBV4L=ON \
-D BUILD_opencv_python2=OFF \
-D BUILD_opencv_python3=ON \
-D BUILD_TESTS=OFF \
-D BUILD_PERF_TESTS=OFF \
-D BUILD_EXAMPLES=OFF \
-D WITH_TBB=ON \
-D BUILD_opencv_world=OFF \
-D BUILD_opencv_xfeatures2d=OFF \
-D WITH_OPENGL=ON \
-D WITH_GTK_2_X=ON \
-D OPENCV_ENABLE_NONFREE=ON \
-D EIGEN_INCLUDE_PATH="/usr/include/eigen3" \
-D OPENCV_EXTRA_MODULES_PATH=../../opencv_contrib/modules \
-D WITH_XINE=ON \
-D WITH_GDAL=ON \
..

make -j8

此處8為最大支持線程數，一般為cpu數兩倍，一般情況下為4核8線程，線程數過多時可能減低編譯效率，設置導致編譯報錯。

make時如看到

$ make
make: * No targets specified and no makefile found. Stop.

此時問題為Cmake出現問題，請查看Cmake報錯信息

3.安裝

編譯成功后

sudo make install
sudo ldconfig

sudo vim /etc/bash.bashrc

在末尾添加，此處是vim編輯器，如果不會使用請百度“如何在vim末尾添加”“vim編輯器如何保存退出”

PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/usr/local/lib/pkgconfig
export PKG_CONFIG_PATH

保存退出

source /etc/bash.bashrc
sudo updatedb

配置生效
查看Linux opencv安裝庫

pkg-config opencv --libs

查看安裝版本

pkg-config opencv --modversion

4. vscode的配置

下載和安裝vscode

略
注意下載C/C++插件

vscode環境配置

創建一個文件夾，作為我們的工作文件夾，之后的opencv代碼需要在此文件夾中運行

launch.json

這個文件主要是配置debug，具體設置如下：

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "name": "(gdb) Launch",
            "type": "cppdbg",
            "request": "launch",
            "program": "${workspaceFolder}/${fileBasenameNoExtension}.o",
            "args": [],
            "stopAtEntry": false,
            "cwd": "${workspaceFolder}",
            "environment": [],
            "externalConsole": true,
            "MIMode": "gdb",
            "miDebuggerPath": "/usr/bin/gdb",
            "preLaunchTask": "g++",
            "setupCommands": [
                {
                    "description": "Enable pretty-printing for gdb",
                    "text": "-enable-pretty-printing",
                    "ignoreFailures": true
                }
            ],
            "miDebuggerArgs": "-q -ex quit; wait() { fg >/dev/null; }; /bin/gdb -q --interpreter=mi",
        },
    ]
}

task.json

一般情況下，在上一步運行失敗之后，會直接提示你設置task.json文件，如果沒有，你也可以點擊Ctrl+Shift+P"調出命令面板，然后搜索Task，點擊第一個

Tasks:Configure Default Build Task

會提示你依據模板創建task.json，這里不管什么模板，隨便選一個，然后直接復制粘貼以下設置代碼：

{
    // See https://go.microsoft.com/fwlink/?LinkId=733558
    // for the documentation about the tasks.json format
    "version": "2.0.0",
    "command": "g++",
    "args": [
        "-g", "-std=c++11", "${file}", "-o", "${fileBasenameNoExtension}.o",// 設置動態鏈接庫
        "-I", "/usr/local/include",
        "-I", "/usr/local/include/opencv",
        "-I", "/usr/local/include/opencv2",
        "-L", "/usr/local/lib",
        "-l", "opencv_core",
        "-l", "opencv_imgproc",
        "-l", "opencv_imgcodecs",
        "-l", "opencv_video",
        "-l", "opencv_ml",
        "-l", "opencv_highgui",
        "-l", "opencv_objdetect",
        "-l", "opencv_flann",
        "-l", "opencv_imgcodecs",
        "-l", "opencv_photo",
        "-l", "opencv_videoio"
    ],// 編譯命令參數
    "problemMatcher":{
        "owner": "cpp",
        "fileLocation":[
            "relative",
            "${workspaceFolder}"
        ],
        "pattern":[
            {
                "regexp": "^([^\\\\s].*)\\\\((\\\\d+,\\\\d+)\\\\):\\\\s*(.*)$",
                "file": 1,
                "location": 2,
                "message": 3
            }
        ]
    },
    "group": {
        "kind": "build",
        "isDefault": true
    }
}

里面有很多參數是適配opencv的

OpenCV 編譯環境配置

配置opencv，其實主要就解決兩個問題，一個是頭文件包含，一個是庫文件搜索。頭文件包含在c_cpp_properties.json中解決，庫文件包含則要繼續修改task.json中的編譯命令。首先來看c_cpp_properties.json：

c_cpp_properties.json

怎么打開這個文件呢，兩種方式，一個就是打開命令面板（還記得那個快捷鍵嗎？我一直記，一直忘），然后搜索cpp: Edit，點擊結果就可以進入這一文件。
另一種就是在自己的cpp文件里直接包含opencv庫，聰明的cpp擴展會給你一個小提示提醒你打開c_cpp_properties.json設置頭文件包含。
不說廢話：

{
    "configurations": [
        {
            "name": "Linux",
            "includePath": [
                "${workspaceFolder}/**",
                "/usr/local/include", //請確保你的opencv opencv2頭文件夾安裝在這個目錄
                "/usr/include"
            ],
            "defines": [],
            "compilerPath": "/usr/bin/gcc",
            "cStandard": "c11",
            "cppStandard": "c++17",
            "intelliSenseMode": "clang-x64"
        }
    ],
    "version": 4
}

測試代碼

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace std;
using namespace cv;

int main()
{
	Mat img = imread("xxxx"); //xxxx為圖片路徑，絕對路徑
	imshow("test", img);
	waitKey(0);
	return 0;
}

隨便找一張圖片，放在某個路徑然后替換imread函數的參數
運行后，我彈出報錯了

提示我 無法打開"raise.c":無法讀取文件.........
需要安裝glibc-source
在終端中輸入

$ sudo apt install glibc-source

然后在launch.json中的"configurations"下添加

"sourceFileMap": {
    "/build/glibc-YYA7BZ": "/usr/src/glibc"
}

其中"YYA7BZ"要改為報錯信息中顯示的glibc后綴
比如我的是

"sourceFileMap": {
    "/build/glibc-eX1tMB": "/usr/src/glibc"
},

這個要根據你們彈出的錯誤去看
然后發現成功運行！