Example: hwdrivers_camera_capture_dialog

C++ example source code:

/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2022, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */

#include <mrpt/gui/CDisplayWindow.h>
#include <mrpt/hwdrivers/CCameraSensor.h>
#include <mrpt/img/CImage.h>
#include <mrpt/system/CTicTac.h>

#include <chrono>
#include <iostream>
#include <thread>

using namespace mrpt;
using namespace mrpt::gui;
using namespace mrpt::obs;
using namespace mrpt::hwdrivers;
using namespace mrpt::img;
using namespace std;

// ------------------------------------------------------
//              TestCameraCaptureAsk
// ------------------------------------------------------
void TestCameraCaptureAsk()
{
    CCameraSensor::Ptr cam = prepareVideoSourceFromUserSelection();

    if (!cam)
    {
        cerr << "The user didn't pick any camera. Exiting." << endl;
        return;
    }

    CDisplayWindow win("Live video");

    cout << "Press 's' to save frames.\nClose the window to exit.\n";

    double counter = 0;
    mrpt::system::CTicTac tictac;

    while (win.isOpen())
    {
        if (!counter) tictac.Tic();

        mrpt::obs::CObservation::Ptr obs = cam->getNextFrame();
        ASSERT_(obs);

        CImage* img = nullptr;

        if (IS_CLASS(*obs, CObservationImage))
        {
            CObservationImage::Ptr o =
                std::dynamic_pointer_cast<CObservationImage>(obs);
            img = &o->image;
        }
        else if (IS_CLASS(*obs, CObservationStereoImages))
        {
            CObservationStereoImages::Ptr o =
                std::dynamic_pointer_cast<CObservationStereoImages>(obs);
            img = &o->imageRight;
        }
        else if (IS_CLASS(*obs, CObservation3DRangeScan))
        {
            CObservation3DRangeScan::Ptr o =
                std::dynamic_pointer_cast<CObservation3DRangeScan>(obs);
            if (o->hasIntensityImage) img = &o->intensityImage;
        }

        if (img) win.showImage(*img);

        if (++counter == 10)
        {
            double t = tictac.Tac();
            cout << "Frame Rate: " << counter / t << " fps" << endl;
            counter = 0;
        }

        // Process keystrokes:
        if (mrpt::system::os::kbhit())
        {
            const int key_code = mrpt::system::os::getch();
            switch (key_code)
            {
                case 's':
                case 'S':
                {
                    static int cnt = 0;
                    const std::string sFile =
                        mrpt::format("frame%05i.png", cnt++);
                    cout << "Saving frame to: " << sFile << endl;
                    img->saveToFile(sFile);
                }
                break;
                default: break;
            };
        }

        std::this_thread::sleep_for(2ms);
    }

    cout << "Closing..." << endl;
}

// ------------------------------------------------------
//                      MAIN
// ------------------------------------------------------
int main()
{
    try
    {
        TestCameraCaptureAsk();

        return 0;
    }
    catch (const std::exception& e)
    {
        std::cerr << "MRPT error: " << mrpt::exception_to_str(e) << std::endl;
        return -1;
    }
    catch (...)
    {
        printf("Untyped exception!!");
        return -1;
    }
}