Qt + OpenCV development (two)-use label to display pictures and package and release

Series of articles:
QT + Opencv development (1)-environment configuration

Features

Realize the functions of opening files, reading image data, sliding bar control binarization, canny, Gaussian blur parameters and displaying processed pictures.

Function realization

Build interface

First build the interface

Code

The most critical code is in mainwindow.cpp, as follows:

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "opencv2/opencv.hpp"
#include "QFileDialog"
#include "QtDebug"

cv::Mat _src;
MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    
    
    ui->setupUi(this);

    // 选取文件
    connect(ui->btn_openFile,&QPushButton::clicked,[=](){
    
    

        //点击选取文件按钮，弹出文件对话框
        QString path = QFileDialog::getOpenFileName(this,"打开文件","E:/Pictures/");

        //将路径放入到lineEdit中
        ui->show_filePath->setText(path);
        _src = cv::imread(path.toStdString());

        if(_src.empty())
        {
    
    
            qDebug() << "could not load the image...";
            return;
        }

        cv::Mat src = _src.clone();
        cv::cvtColor(src, src, cv::COLOR_BGR2RGB);
        QImage img = QImage(src.data, src.cols, src.rows, src.step, QImage::Format_RGB888);
//        int w = img.width();
//        int h = img.height();
//        if(w > 800 || h > 800)
//        {
    
    
//            double rate = 888.0 / std::max(w, h);
//            int nw = static_cast<int>(rate * w);
//            int nh = static_cast<int>(rate * h);
//            img = img.scaled(QSize(nw, nh), Qt::KeepAspectRatio);

//        }
        QPixmap mp;
        mp = mp.fromImage(img);
        ui->label_src->setPixmap(mp);
        ui->label_src->setAlignment(Qt::AlignCenter);
        src.release();
    });

    // canny提取边缘
    connect(ui->btn_canny,&QPushButton::clicked,[=](){
    
    


        cv::Mat src = _src.clone();
        if(src.empty())
        {
    
    
            qDebug() << "could not load the image...";
            return;;
        }
        cv::cvtColor(src, src, cv::COLOR_BGR2GRAY);
        cv::Mat edge;
        ui->text_cannyLowValue->setText(QString::number(ui->slider_cannyLowValue->value()));
        ui->text_cannyHighValue->setText(QString::number(ui->slider_cannyHighValue->value()));
        cv::Canny(src, edge, ui->slider_cannyLowValue->value(), ui->slider_cannyHighValue->value());
        QImage img = QImage(edge.data, edge.cols, edge.rows, edge.step, QImage::Format_Grayscale8);

        QPixmap mp;
        mp = mp.fromImage(img);
        ui->label_canny->setPixmap(mp);
        ui->label_canny->setAlignment(Qt::AlignCenter);
        src.release();
    });

    // 二值化
    connect(ui->btn_binary,&QPushButton::clicked,[=](){
    
    


        cv::Mat src = _src.clone();
        if(src.empty())
        {
    
    
            qDebug() << "could not load the image...";
            return;
        }
        cv::cvtColor(src, src, cv::COLOR_BGR2GRAY);
        cv::Mat bin;
        ui->text_binaryValue->setText(QString::number(ui->slider_binaryValue->value()));
        cv::threshold(src, bin, ui->slider_binaryValue->value(), 255, cv::THRESH_BINARY);
        QImage img = QImage(bin.data, bin.cols, bin.rows, bin.step, QImage::Format_Grayscale8);

        QPixmap mp;
        mp = mp.fromImage(img);
        ui->label_binary->setPixmap(mp);
        ui->label_binary->setAlignment(Qt::AlignCenter);
        src.release();
    });

    //高斯模糊
    connect(ui->btn_gauss, &QPushButton::clicked,[=](){
    
    
        cv::Mat pic = _src.clone();
        if(pic.empty())
        {
    
    
            qDebug()<<"could not load image ...";
            return;
        }

        cv::Mat gauss_img;
        int Ksize =2 * ui->slider_gaussKernalSize->value() + 1;
        ui->text_gaussKernalSize->setText(QString::number(Ksize));
        cv::GaussianBlur(pic, gauss_img, cv::Size(Ksize, Ksize), 1, 1);
        QImage img = QImage(gauss_img.data, gauss_img.cols, gauss_img.rows, gauss_img.step, QImage::Format_BGR888);

        QPixmap mp;
        mp = mp.fromImage(img);
        ui->label_draw->setPixmap(mp);
        ui->label_draw->setAlignment(Qt::AlignCenter);
        pic.release();
    });

}






MainWindow::~MainWindow()
{
    
    
    delete ui;
    _src.release();
}

function display

Bale

windeployqt

Windeployqt is a packaging tool that comes with QT5. It can find all library files used by the program (exe) and copy them to the current file of the exe program.

1. Create a new folder, name it my_release, and copy the exe file generated after the above run into it.

2. Open the command prompt as an administrator and enter the current folder

cd /d E:\workSpace\qt_workspace\build-opencv_startDemo-Desktop_Qt_5_15_2_MinGW_64_bit-Release\my_release

Pay attention to the path to write your own path, I am just showing it here.

3. Use windeployqt for packaging

enter:

windeployqt opencv_startDemo.exe

The format is: windeployqt The name of the program you want to package. It

should be noted that you must ensure that windeployqt.exe is already in the environment variable, otherwise there will be an error in this step. If you make a mistake, you can find the location of windeployqt.exe, as shown in the figure below. Just add it to the system environment variable.

Packaged folder:

Pack the folder as a whole to others, and they can run the program.

Postscript: If you package it to someone else, you may encounter errors such as not finding libopencv_world450.dll, libgomp-1.dll, etc. after others run it, you have to find the corresponding library on your computer and copy it to the other party, and put it in the package file. It's running. (Libgomp-1.dll can be found under yourPath\Qt_5.15.2\Tools\mingw810_64\bin)

HM NIS Edit + NSIS

On the basis of the previous step, you can also use the third-party packaging tool HM NIS Edit to further package and generate the wizard-driven installation program Setup.exe

HM NIS Edit download: http://hmne.sourceforge.net/
NSIS: https://nsis.sourceforge.io/Download

After installing these two, you need to open HM NIS Edit to configure the NSIS compiler, otherwise there is no language option when creating a wizard script.

Packaging tutorial:
Reference: https://www.cnblogs.com/yply/p/12001813.html

According to the previous tutorial, there is only one step:

After the packaging is complete, you will get the wizard with the installation program Setup.exe

After sending the installation program to others, others can use custom installation paths and other operations (just like the installation package we usually download).

Other packaging tools:
Engima Virtual Box Download link: http://enigmaprotector.com/en/downloads.html

Use tutorial: https://blog.csdn.net/kangshuaibing/article/details/84951619
You can try it.

Common mistakes in packaging

After Qt software was packaged, it reported an error "Unable to locate program input point_ZN10QArrayData10deallocateEPs_jj on the dynamic link library....exe.

This is caused by the difference between the compilation tool used when building the project and the compilation tool used when packaging the software.
Solution: select the corresponding compilation tool when packaging.

Reference: https://blog.csdn.net/weijifen000/article/details/102537640

related information

• int to Qstring:

Qstring::number(int value)