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c++qtqgraphicsview

Removing Qpixmap from QGraphicsScene

I enconutered a problem, when dealing with QGraphicsScene and QPixmap. I am sequentially displaying frames, captured by the camera. QTimer object is calling updateSingleView() function every 100ms. That is my inner function:

void CCIGui::updateSingleView()
{

    unsigned char *const img = PGRSystem->SnapShot();

    QImage Img(img, 1024, 768, QImage::Format_RGB888);

    scenes.at(0)->removeItem(scenes.at(0)->items().at(0));
    scenes.at(0)->addPixmap(QPixmap::fromImage(Img));

    ui_camViews.at(0).graphicsView->setScene(scenes.at(0));

    delete [] img;
}

Gui is displaying the camera's view but unfortunatelly there is a memory leak, when calling scenes.at(0)->addPixmap(QPixmap::fromImage(Img)); I thought that removeItem function should destroy the old QPixmap, but apparently its not. Do you know why the leak occurs and how to solve it?

Solution

  • As suggested

    you need to delete the item after removeItem line.

    i.e

    QPointer _item = scenes.at(0)->items().at(0); scenes.at(0)->removeItem( _item ); delete _item;

    scenes.at(0)->addPixmap(QPixmap::fromImage(Img));

    .....