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Draw buffer

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  • hjparkH Offline
    hjparkH Offline
    hjpark
    wrote on last edited by
    #1

    Hi Guys,

    I'm in trouble to draw a buffer on widget.. this is my code

        int imageWidth = IMAGE_WIDTH;
        int imageHeight = IMAGE_HEIGHT;
        int bytesPerPixel = 2; 
        int format = QImage::Format_RGB16; 
        QImage image( m_pCameraBuf[DATA_DEPTH], imageWidth, imageHeight, imageWidth * bytesPerPixel, format);
        painter.drawImage(30,100, image);
    

    unsigned short *m_pCameraBuf[TOTAL]; is defined in the class and I allocated memory with malloc before this code.

    and then I tried to compile it but facing the error below.

    error: no matching function for call to 'QImage::QImage(short unsigned int*&, int&, int&, int, int&)'
    QImage image( m_pCameraBuf[DATA_DEPTH], imageWidth, imageHeight, imageWidth * bytesPerPixel, format);
    ^
    I'm a beginner . sorry but please help me to know what's wrong on my code..
    thanks a lot.

                                                                                                                              ^
    
    1 Reply Last reply
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    • jsulmJ Offline
      jsulmJ Offline
      jsulm
      Lifetime Qt Champion
      wrote on last edited by jsulm
      #2

      Your m_pCameraBuf is of type short[], right? It has to be a uchar array. See here http://doc.qt.io/qt-5/qimage.html#QImage-3

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

      1 Reply Last reply
      0
      • jsulmJ Offline
        jsulmJ Offline
        jsulm
        Lifetime Qt Champion
        wrote on last edited by
        #3

        And why m_pCameraBuf[DATA_DEPTH] and not just m_pCameraBuf?

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

        hjparkH 1 Reply Last reply
        0
        • jsulmJ jsulm

          And why m_pCameraBuf[DATA_DEPTH] and not just m_pCameraBuf?

          hjparkH Offline
          hjparkH Offline
          hjpark
          wrote on last edited by
          #4

          @jsulm
          Thanks a lot for your help..

          An external API " mtfReadFromDevice(m_hnDevice, (unsigned short**)m_pCameraBuf); " requires 2 buffers

          unsigned short *m_pCameraBuf[TOTAL] => #define TOTAL 2

          and, I can't change the code of mtfReadFromDevice becuase it has been provided with lib only

          so, I tried to cast short to uchar like it
          QImage image( (uchar *)m_pCameraBuf[DATA_DEPTH])

          but, facing

          error: invalid user-defined conversion from 'uchar* {aka unsigned char*}' to 'const QString&' [-fpermissive]
          QImage image((uchar*)m_pCameraBuf[DATA_DEPTH]);

                                                            ^
          

          Please help me again.. thanks..

          jsulmJ 1 Reply Last reply
          0
          • hjparkH hjpark

            @jsulm
            Thanks a lot for your help..

            An external API " mtfReadFromDevice(m_hnDevice, (unsigned short**)m_pCameraBuf); " requires 2 buffers

            unsigned short *m_pCameraBuf[TOTAL] => #define TOTAL 2

            and, I can't change the code of mtfReadFromDevice becuase it has been provided with lib only

            so, I tried to cast short to uchar like it
            QImage image( (uchar *)m_pCameraBuf[DATA_DEPTH])

            but, facing

            error: invalid user-defined conversion from 'uchar* {aka unsigned char*}' to 'const QString&' [-fpermissive]
            QImage image((uchar*)m_pCameraBuf[DATA_DEPTH]);

                                                              ^
            

            Please help me again.. thanks..

            jsulmJ Offline
            jsulmJ Offline
            jsulm
            Lifetime Qt Champion
            wrote on last edited by
            #5

            @hjpark Please use the same QImage constructor a before:

            QImage image(reinterpret_cast<uchar*>(m_pCameraBuf), imageWidth, imageHeight, imageWidth * bytesPerPixel, format);
            

            And why do you pass m_pCameraBuf[DATA_DEPTH] and not m_pCameraBuf?

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

            hjparkH 1 Reply Last reply
            0
            • jsulmJ jsulm

              @hjpark Please use the same QImage constructor a before:

              QImage image(reinterpret_cast<uchar*>(m_pCameraBuf), imageWidth, imageHeight, imageWidth * bytesPerPixel, format);
              

              And why do you pass m_pCameraBuf[DATA_DEPTH] and not m_pCameraBuf?

              hjparkH Offline
              hjparkH Offline
              hjpark
              wrote on last edited by
              #6

              @jsulm

              hi..

              I tried to compile with QT5.2.1 instaed of 5.7 and no more error with this code.. an it works well.

              QImage image( (uchar*) m_pCameraBuf[DATA_DEPTH], imageWidth, imageHeight, imageWidth * bytesPerPixel, QImage::Format_RGB16, Q_NULLPTR, Q_NULLPTR);

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