Hi,
I am not a C++ guru, but I think your memory leak issue is linked with
QSharedPointer usage.
I think you have to delete the connection to remove the lambda and destroy the
QSharedPointer.
Like this:
void Utils::takeScreenshot()
{
QQuickItem *item = m_rootView->contentItem();
QSharedPointer<QQuickItemGrabResult> grab = item->grabToImage();
if(grab.get() != nullptr) {
connect(grab.get(), &QQuickItemGrabResult::ready, this, [grab]() {
garb.get()->disconnect();
qInfo() << "<<< Utils::takeScreenshot ";
});
}
}
Regards
Fabrice
Von: Interest <[email protected]> Im Auftrag von Marc Van Daele
Gesendet: Montag, 10. August 2020 10:32
An: Qt Interest <[email protected]>
Betreff: [Interest] Memory leak in grabToImage?
Hello,
The following example application has a memory leak when using 5.12.6 on Linux
(when monitoring with htop, the memory of the process increases systematically).
Is this a programming error or a bug in Qt?
Looking forward to your input,
Marc
In QML, I take a screenshot every second
Timer {
id: memoryMonitor
interval: 1*1000
repeat: true
onTriggered: utils.takeScreenshot()
}
Component.onCompleted: memoryMonitor.start()
In main.cpp, I register my Utils class as a context property
Utils utils((QQuickWindow*)(app.allWindows()[0]));
engine.rootContext()->setContextProperty("utils", &utils);
My Utils class looks like
class Utils : public QObject
{
Q_OBJECT
public:
explicit Utils(QQuickWindow* rootView, QObject *parent = nullptr);
Q_INVOKABLE void takeScreenshot();
signals:
public slots:
private:
QQuickWindow* m_rootView;
};
Utils::Utils(QQuickWindow* rootView, QObject *parent) : QObject(parent)
{
m_rootView = rootView;
}
void Utils::takeScreenshot()
{
QQuickItem *item = m_rootView->contentItem();
QSharedPointer<QQuickItemGrabResult> grab = item->grabToImage();
if(grab.get() != nullptr) {
connect(grab.get(), &QQuickItemGrabResult::ready, this, [grab]() {
qInfo() << "<<< Utils::takeScreenshot ";
});
}
}
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