ROS program interface built using QT (C ++)

1. QT development environment to build, maker culture wisdom made reference tutorial https://www.ncnynl.com/archives/201903/2863.html.

ROS need to create a workspace, so you can use CMAKE be compiled and automatically generate CMakeLists.txt file.

$mkdir -p ~/catkin_ws/src  $cd ~/catkin_ws/src  $catkin_init_workspace  $cd ~/catkin_ws  $catkin_make

$cd /src  $catkin_create_qt_pkg robomap

2. The goal is to develop a robot SLAM map building and autonomous navigation interface display interface. Reference record "QT ROS and language Getting Started - ROS published map display the message" Chi-made passenger tutorial that one, also need to define a speed adjustment slider.

　　2.1 mapp.ui interface added Slider, class name to ForBackSlider; The following code modification. The last call of the value of the Slider in qnode.cpp so that the value of the node posted messages geometry_msgs :: Twist equal ForBackSlider.

mapp.cpp:
slider->setMinimum(0);
slider->setMaximum(100);
ui->ForBackSlider->setMinimum(0);
QObject::connect(ui->ForBackSlider,SIGNAL(valueChanged(int)),this,SLOT(set_speed_value(int));
void MAPP::set_speed_value(int slider_value)
{
   ForBackSpeed=slider_value;          
}

mapp.h:
 private slots:
     void set_speed_value(int s);
 private:
     a float ForBackSpeed = 0.0 ; 

the CMakeLists.txt to support :( C ++ . 11 Characteristics)
 SET (CMAKE_CXX_FLAGS " $ {} CMAKE_CXX_FLAGS -std = C ++. 11)

　　2.2 ROS button to start the node, for example: $ roscore, $ roslaunch usb_cam usb_cam_node, etc., that do not have to open a terminal and enter the long list of commands.

main_window.ui: 
insert button, renamed roscore. 

main_window.h: 
Private slots:
     void on_roscore_clicked (); 

main_window.cpp: 
void   robomap :: :: on_roscore_clicked the MainWindow () 
{ 
    System ( " GNOME -terminal the bash the -X--C 'roscore' & " ); 
} 
if you want a button a plurality of start command, to obtain a corresponding number of write system (), respectively, as a newly opened terminal.

　　2.3 Subscribe to the camera.

　　　　Mode 1 (tricky, using the buttons invoke the command):

$roslaunch usb_cam usb_cam_test.launch
参见https://github.com/ros-visualization/rqt_image_view
main_window.cpp:
void robomap::Maindow::on_camera_clicked()
{
　　system("gnome -terminal -x bash -c 'source ~/catkin_ws/devel/setup.bash; rosrun usb_cam usb_cam_node'&");
　　system("gnome -terminal -x bash -c 'rqt_image_view'&");
}

　　　　Second way (without buttons): camera preview and the captured image with reference to the method of example implementations linux commune Qt5, https: //www.linuxidc.com/Linux/2016-03/128792.html

QCamera:: No such file or directory, then compile the original change was not through being given a direct reference. The problem is to determine the problem can not find external libraries and header files. 
In the CMakeLists.txt: 
include_directories (/ usr / the include / x86_64_linux-GNU / QT5 / QtMultimedia) 
was added after the error is eliminated, but there is an error during link: undefined reference to 'QCamera :: ' 
add: target_link_libraries (... Qt5: : Multimedia), only QCameraViewfinder not find an external library. 
Data then ran CMakeLists.txt learning, or can not be solved, but added to find another way to specify the c ++ standard: set ( CMAKE_CXX_STANDARD 11). 

Turn the camera first implementation calls QT interface, the first to realize the function, not the ROS space complete: 
step1: New Qt widgets application engineering 
step2: https: //www.cnblogs.com/annt/p/ant_000.html 
when running: step3 error, install the necessary library. Completion 
cam.pro: 
QT = + Multimedia Core GUI multimediawidgets 

greaterThan (QT_MAJOR_VERSION,. 4): QT = + Widgets 
the TARGET = CAM 
TEMPLATE = App
SOURCES += main.cpp\
        mainwindow.cpp
HEADERS  += mainwindow.h
FORMS    += mainwindow.ui
mainwindow.h:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QCamera>
#include <QCameraViewfinder>
#include <QCameraImageCapture>
#include <QFileDialog>



namespace Ui {
class MainWindow;
}

class QCamera;
class QCameraViewfinder;
class QCameraImageCapture;

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();

private slots:
void captureImage();
void displayImage(int,QImage);
void saveImage();

private:
Ui::MainWindow *ui;

QCamera *camera;
QCameraViewfinder *viewfinder;
QCameraImageCapture *imageCapture;
};

#endif // MAINWINDOW_H
mainwindow.cpp:
#include "mainwindow.h"
#include "ui_mainwindow.h"

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

camera=new QCamera(this);
viewfinder=new QCameraViewfinder(this);
imageCapture=new QCameraImageCapture(camera);

ui->ImageView->addWidget(viewfinder);
ui->ImageCapture->setScaledContents(true);

camera->setViewfinder(viewfinder);
camera->start();

connect(imageCapture, SIGNAL(imageCaptured(int,QImage)), this, SLOT(displayImage(int,QImage)));

connect(ui->buttonCapture, SIGNAL(clicked()), this, SLOT(captureImage()));
connect(ui->buttonSave, SIGNAL(clicked()), this, SLOT(saveImage()));
connect(ui->buttonQuit, SIGNAL(clicked()), qApp, SLOT(quit()));
}

MainWindow::~MainWindow()
{
delete ui;
}

void MainWindow::captureImage()
{
ui->statusBar->showMessage(tr("capturing..."), 1000);
imageCapture->capture();
}

void MainWindow::displayImage(int , QImage image)
{
ui->ImageCapture->setPixmap(QPixmap::fromImage(image));

ui-> statusBar-> showMessage (TR ( "Capture the OK!"), 5000); 
} 

void the MainWindow :: saveimage () 
{ 
QString fileName = QFileDialog :: getSaveFileName (the this, TR ( "File Save"), the QDir :: HOMEPATH (), TR ( "jpegfile (* JPG).")); 
IF (fileName.isEmpty ()) { 
ui-> statusBar-> showMessage (TR ( "Cancel Save"), 5000); 
return; 
} 
const QPixmap a pixmap = ui- *> ImageCapture-> a pixmap (); 
IF (a pixmap) { 
pixmap-> Save (fileName); 
ui-> statusBar-> showMessage (TR ( "Save the OK"), 5000); 
} 
} 
function may be implemented . Call camera, capture, save and so on. 


Followed by the code in the ROS modified space. (Search to a blog, is CMAKE compile the project, you need to add qt library CMakeLists file) (Ubuntu under Qt Multimedia play mp3 files Note) 
CMakeLists.txt:

set (QT_LIBRARIES Qt5 :: Widgets Qt5 :: SerialPort Qt5 :: Multimedia) 
with reference to the wording of a blog, join MultimediaWidgets module, compiled successfully 


3. Turn turtlebot simulation, verification procedures. 
APT-GET install ROS sudo-ROS-Kinetic Kinetic-turtlebot-turtlebot-Apps-turtlebot-RO-Kinetic Kinetic-turtlebot Interactions ROS-ROS-sumulatio-Kinetic-kobuki-FTDI 
Source /opt/ros/kinetic/setup.bash 
roslaunch turtlebot_gazebo turtlebot_world.launch need to wait a few minutes to load 
roslaunch turtlebot_gazebo gmapping_demo.launch 
roslaunch turtlebot_teleop keyboard_teleop.launch