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A camera problem.

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  • J jenya7

    @JonB said in A camera problem.:

    @jenya7 said in A camera problem.:

    I put a break point in the MainWindow constructor and Camera constructor and see which hits the first.

    And what was the result?!

    I see the Camera object is created before MainWindow::MainWindow(QWidget *parent) constructor.

    At the time your Camera::setCamera() is called, has v_finder = new QCameraViewfinder(this); been executed yet? If not then v_finder in m_camera->setViewfinder(v_finder) will be nullptr....

    m_camera->setViewfinder(v_finder) is executed first

    JonBJ Online
    JonBJ Online
    JonB
    wrote on last edited by
    #82

    @jenya7
    Then obviously it is not the right place to put m_camera->setViewfinder(v_finder);.... You cannot execute that line until both m_camera & v_finder have been initialized, so move it somewhere suitable.

    J 2 Replies Last reply
    1
    • JonBJ JonB

      @jenya7
      Then obviously it is not the right place to put m_camera->setViewfinder(v_finder);.... You cannot execute that line until both m_camera & v_finder have been initialized, so move it somewhere suitable.

      J Offline
      J Offline
      jenya7
      wrote on last edited by
      #83

      @JonB said in A camera problem.:

      @jenya7
      Then obviously it is not the right place to put m_camera->setViewfinder(v_finder);.... You cannot execute that line until both m_camera & v_finder have been initialized, so move it somewhere suitable.

      I'll try

      1 Reply Last reply
      0
      • M Offline
        M Offline
        mchinand
        wrote on last edited by
        #84

        It seems your code is largely based on the Camera Example; is that correct? Does that example work for you unmodified?

        J 1 Reply Last reply
        0
        • M mchinand

          It seems your code is largely based on the Camera Example; is that correct? Does that example work for you unmodified?

          J Offline
          J Offline
          jenya7
          wrote on last edited by
          #85

          @mchinand said in A camera problem.:

          It seems your code is largely based on the Camera Example; is that correct? Does that example work for you unmodified?

          It's a widget based example. I removed all widget related stuff cause I don't have all these controls for camera operating in my app. I control the camera with commands I type in a terminal.

          jsulmJ 1 Reply Last reply
          0
          • J jenya7

            @mchinand said in A camera problem.:

            It seems your code is largely based on the Camera Example; is that correct? Does that example work for you unmodified?

            It's a widget based example. I removed all widget related stuff cause I don't have all these controls for camera operating in my app. I control the camera with commands I type in a terminal.

            jsulmJ Offline
            jsulmJ Offline
            jsulm
            Lifetime Qt Champion
            wrote on last edited by
            #86

            @jenya7 Come on, the question is whether this example works with your camera or not! Can't you simply try that?

            https://forum.qt.io/topic/113070/qt-code-of-conduct

            J 1 Reply Last reply
            3
            • jsulmJ jsulm

              @jenya7 Come on, the question is whether this example works with your camera or not! Can't you simply try that?

              J Offline
              J Offline
              jenya7
              wrote on last edited by jenya7
              #87

              @jsulm said in A camera problem.:

              @jenya7 Come on, the question is whether this example works with your camera or not! Can't you simply try that?

              I'll try tomorrow. I have to get a camera.

              well...in the original example I press on Capture Photo and it stays inactive forever.

              J.HilkJ 1 Reply Last reply
              0
              • J Offline
                J Offline
                jenya7
                wrote on last edited by jenya7
                #88

                How can I pass a default camera instance to use it later?
                In camera.h

                class Camera : public QMainWindow
                {
                    Q_OBJECT
                
                    public:
                    Camera();
                    void Camera::setCamera(const QCameraInfo &cameraInfo);
                
                    const QCameraInfo* default_camera;   
                }
                

                in camera.cpp in a constructor

                if (cameraInfo == QCameraInfo::defaultCamera())
                {
                       default_camera = new QCameraInfo(cameraInfo );
                        videoDeviceAction->setChecked(true);
                }
                

                in main.cpp

                g_camera.SetCamera(g_camera.default_camera );
                

                I get
                error: reference to type 'const QCameraInfo' could not bind to an lvalue of type 'const QCameraInfo *'

                1 Reply Last reply
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                • J jenya7

                  @jsulm said in A camera problem.:

                  @jenya7 Come on, the question is whether this example works with your camera or not! Can't you simply try that?

                  I'll try tomorrow. I have to get a camera.

                  well...in the original example I press on Capture Photo and it stays inactive forever.

                  J.HilkJ Online
                  J.HilkJ Online
                  J.Hilk
                  Moderators
                  wrote on last edited by
                  #89

                  @jenya7 said in A camera problem.:

                  I'll try tomorrow. I have to get a camera.

                  wait!

                  how do you expect the state to change to a ready for capture == true, when you have no camera connected that could be used ?


                  Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


                  Q: What's that?
                  A: It's blue light.
                  Q: What does it do?
                  A: It turns blue.

                  J 1 Reply Last reply
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                  • J.HilkJ J.Hilk

                    @jenya7 said in A camera problem.:

                    I'll try tomorrow. I have to get a camera.

                    wait!

                    how do you expect the state to change to a ready for capture == true, when you have no camera connected that could be used ?

                    J Offline
                    J Offline
                    jenya7
                    wrote on last edited by jenya7
                    #90

                    @J-Hilk said in A camera problem.:

                    @jenya7 said in A camera problem.:

                    I'll try tomorrow. I have to get a camera.

                    wait!

                    how do you expect the state to change to a ready for capture == true, when you have no camera connected that could be used ?

                    It's connected. The constructor detects it - "dev/video0".

                    I just wonted to try the original example on Windows. my app is running on Linux.

                    1 Reply Last reply
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                    • JonBJ JonB

                      @jenya7
                      Then obviously it is not the right place to put m_camera->setViewfinder(v_finder);.... You cannot execute that line until both m_camera & v_finder have been initialized, so move it somewhere suitable.

                      J Offline
                      J Offline
                      jenya7
                      wrote on last edited by
                      #91

                      @JonB said in A camera problem.:

                      @jenya7
                      Then obviously it is not the right place to put m_camera->setViewfinder(v_finder);.... You cannot execute that line until both m_camera & v_finder have been initialized, so move it somewhere suitable.

                      I resolved the issue. Now I get

                      Ready for capture: true

                      But on takeImage

                      QWidget::paintEngine: Should no longer be called
                      CameraBin warning: "Resource busy or not available."

                      1 Reply Last reply
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