从 QGraphicsScene 中删除 Qpixmap
在处理 QGraphicsScene 和 QPixmap 时，我遇到了一个问题。 我按顺序显示相机捕获的帧。 QTimer 对象每 100 毫秒调用一次 updateSingleView() 函数。这是我的内部功能：
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 正在显示相机的视图，但不幸的是，在调用 scenes.at(0)->addPixmap(QPixmap::fromImage(Img)); 时出现内存泄漏认为 removeItem 函数应该销毁旧的 QPixmap，但显然事实并非如此。您知道为什么会出现泄漏以及如何解决吗？
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?
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来自 Qt 文档：
因此，您需要使用
delete手动删除该项目。http://doc.trolltech.com/4.7/qgraphicsscene.html#removeItem
From the Qt documentation:
Hence you need to delete the item using
deletemanually.http://doc.trolltech.com/4.7/qgraphicsscene.html#removeItem
根据建议，
您需要在removeItem行之后删除该项目。
即
QPointer _item = Scenes.at(0)->items().at(0);
scene.at(0)->removeItem( _item );
删除_item；
scene.at(0)->addPixmap(QPixmap::fromImage(Img));
……
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));
.....