从QGraphicsScene删除Qpixmap [英] Removing Qpixmap from QGraphicsScene

问题描述

我处理一个问题，当处理QGraphicsScene和QPixmap。
我按顺序显示相机捕获的帧。 QTimer对象每100ms调用一次updateSingleView（）函数。这是我的内在函数：

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显示相机的视图，但不幸的是有内存泄漏， scenes.at（0） - > addPixmap（QPixmap :: fromImage（Img））; 我认为 removeItem 函数应该销毁旧的QPixmap，但显然它不是。您是否知道为什么会发生泄漏以及如何解决？

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?

推荐答案

如建议

您需要在removeItem行之后删除该项。

you need to delete the item after removeItem line.

即

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

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

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

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

.....

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