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QCamera focus over some area, suggestions.

  • HI, I'm developing a program in c++ for security camera for my neighbourhood that uses a webcam (I'm using my webcam to test).
    I'm using a QCameraFocus to zoom in and zoom out using the zoomTo() function, it works, but it just focuses in the center, and I would like to zoom over some area, like the corner in the view. I tried using setCustomFocusPoint but it didn't work. Also I would like to rotate some degrees.
    I would like to receive some suggestions to get zoom over any area and rotate some degrees.

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  • Lifetime Qt Champion


    Does your camera provider offer any API for that ?

  • @SGaist , I'm currently testing with my laptop webcam (according lsusb command Chicony Electronics is the information about my webcam), but for my project deploy I'm going to use a Logitech webcam c270. I've been looking for information about some API of my webcam, but I did not found something related with Qt.

  • Lifetime Qt Champion

    Qt cannot cover every possible APIs. By the way what OS are you running ? They do not all offer all the range of controls.

  • @SGaist , I'm running in ubuntu 18, but I tried in windows as well, and the results is the same. I'm thinking to convert the data from the camera to image, cut, rotate and set them over a QLabel, but I don't know if this method is going to be the best way, because I would like to capture 15 fps at less.

  • Lifetime Qt Champion

    Are you planning to do any image processing on these image beside zooming ?

  • @SGaist , I just need zooming and rotate some area of the camera capture, I thought that I could achieve using only QCameraFocus or relative libraries but I guess I have to use another method.

  • What does isFocusPointModeSupported(QCameraFocus::FocusPointCustom) return?
    And if I need to rotate a video in Qt, I would start from QGraphicsVideoItem in a QGraphicsView. Don't know whether that would work though...
    Do you want to rotate a single still image file or the whole video widget?

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