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  4. QImage to Qpixmap conversion is too slow

QImage to Qpixmap conversion is too slow

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  • Christian EhrlicherC Online
    Christian EhrlicherC Online
    Christian Ehrlicher
    Lifetime Qt Champion
    wrote on last edited by
    #12

    Do you update your image from a different thread? If so you should learn about threading: Threading Basics

    Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
    Visit the Qt Academy at https://academy.qt.io/catalog

    L 1 Reply Last reply
    3
    • Christian EhrlicherC Christian Ehrlicher

      Do you update your image from a different thread? If so you should learn about threading: Threading Basics

      L Offline
      L Offline
      lansing
      wrote on last edited by
      #13

      @Christian-Ehrlicher

      HI, is this related to the crash?

      mrjjM 1 Reply Last reply
      0
      • L lansing

        @Christian-Ehrlicher

        HI, is this related to the crash?

        mrjjM Offline
        mrjjM Offline
        mrjj
        Lifetime Qt Champion
        wrote on last edited by
        #14

        @lansing

        Hi
        yes if you do it from another thread then very much yes.

        L 1 Reply Last reply
        0
        • mrjjM mrjj

          @lansing

          Hi
          yes if you do it from another thread then very much yes.

          L Offline
          L Offline
          lansing
          wrote on last edited by
          #15

          @mrjj

          I don't have threading in the program.

          mrjjM 1 Reply Last reply
          0
          • L lansing

            @mrjj

            I don't have threading in the program.

            mrjjM Offline
            mrjjM Offline
            mrjj
            Lifetime Qt Champion
            wrote on last edited by
            #16

            @lansing
            Hi
            then something is wrong with the image then.
            Else why crash on copy.

            can you try with Image that you are 100% sure is valid ?

            L 1 Reply Last reply
            0
            • mrjjM mrjj

              @lansing
              Hi
              then something is wrong with the image then.
              Else why crash on copy.

              can you try with Image that you are 100% sure is valid ?

              L Offline
              L Offline
              lansing
              wrote on last edited by lansing
              #17

              @mrjj

              Hi, I have set the image to one in my resource folder for testing, now it has crashed at line m_frameImage = image. I have changed the image argument from const QImage & to QImage*, I don't know if that have a effect on it. But in debug, it did show my image dimension.

              QImage *img= new QImage(":/cross.png");
              myGLPainter->drawImage(img);
              
              mrjjM Christian EhrlicherC SGaistS 3 Replies Last reply
              0
              • L lansing

                @mrjj

                Hi, I have set the image to one in my resource folder for testing, now it has crashed at line m_frameImage = image. I have changed the image argument from const QImage & to QImage*, I don't know if that have a effect on it. But in debug, it did show my image dimension.

                QImage *img= new QImage(":/cross.png");
                myGLPainter->drawImage(img);
                
                mrjjM Offline
                mrjjM Offline
                mrjj
                Lifetime Qt Champion
                wrote on last edited by
                #18

                @lansing
                and it does still crash ?

                1 Reply Last reply
                0
                • L Offline
                  L Offline
                  lansing
                  wrote on last edited by
                  #19

                  Yes, it said

                  error: Debugger encountered an exception: Exception at 0x7ff71b7e9b88, code: 0xc0000005: read access violation at: 0xffffffffffffffff, flags=0x0
                  
                  1 Reply Last reply
                  0
                  • L lansing

                    @mrjj

                    Hi, I have set the image to one in my resource folder for testing, now it has crashed at line m_frameImage = image. I have changed the image argument from const QImage & to QImage*, I don't know if that have a effect on it. But in debug, it did show my image dimension.

                    QImage *img= new QImage(":/cross.png");
                    myGLPainter->drawImage(img);
                    
                    Christian EhrlicherC Online
                    Christian EhrlicherC Online
                    Christian Ehrlicher
                    Lifetime Qt Champion
                    wrote on last edited by
                    #20

                    @lansing said in QImage to Qpixmap conversion is too slow:

                    myGLPainter

                    Where do you initialize this variable?

                    Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                    Visit the Qt Academy at https://academy.qt.io/catalog

                    1 Reply Last reply
                    1
                    • L lansing

                      @mrjj

                      Hi, I have set the image to one in my resource folder for testing, now it has crashed at line m_frameImage = image. I have changed the image argument from const QImage & to QImage*, I don't know if that have a effect on it. But in debug, it did show my image dimension.

                      QImage *img= new QImage(":/cross.png");
                      myGLPainter->drawImage(img);
                      
                      SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on last edited by
                      #21

                      @lansing said in QImage to Qpixmap conversion is too slow:

                      QImage *img= new QImage(":/cross.png");
                      myGLPainter->drawImage(img);

                      That's the wrong thing to do as you will leak images doing so.

                      Beside the initialization issue pointed by @Christian-Ehrlicher can you provide the stack trace of your crash ?

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                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                      1 Reply Last reply
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