Details
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Bug
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Resolution: Out of scope
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P2: Important
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None
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5.12.2, 5.15.0
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None
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visual studio 2017
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Windows
Description
I have a memory leak problem while simply using QPrinter/QPainter in my C++/QT application, to print several pictures to a printer (physical or "print to pdf" printer).
Each time the memory used raise up to about 200/500 Mo each time(depend of number of pictures choosen) with a little test project and *doesnt'n bring back* after print task and coming back to main event loop.
I ever tried some modifications such as put QPrinter and QPainter variable in member of wind object, try in debug mode with VS, or release without it... but it's the same.
Here a code test to illustrate this problem:
```c++
wind::wind(QWidget *parent) : QWidget(parent) {
_printOut = new QPushButton("Print");
connect(_printOut, &QPushButton::clicked, this, &wind::printOut);
QGridLayout *lay = new QGridLayout();
lay->addWidget(_printOut);
_photoPrinterComboBox = new QComboBox(); QStringList printList = QPrinterInfo::availablePrinterNames();
_photoPrinterComboBox->addItems(printList);
_photoPrinterComboBox->setMaximumWidth(250);
_photoPrinterComboBox->setCurrentIndex(0);
lay->addWidget(_photoPrinterComboBox);
setLayout(lay);
show();
}
void wind::printOut(){
QPrinterInfo printerInfo = QPrinterInfo::printerInfo(_photoPrinterComboBox->currentText());
QPrinter printer(printerInfo, QPrinter::HighResolution);
QStringList files = QFileDialog::getOpenFileNames(this, "choisir images", "", "*.jpg", 0);
QPainter paint;
QPixmap img;
for (int i(0); i < files.size(); i++) {
bool succ = img.load(files.at(i));
if (succ) {
QFileInfo fi(files.at(i));
paint.begin(&printer);
qreal dpiX = printer.physicalDpiX();
qreal dpiY = printer.physicalDpiY();
paint.setRenderHint(QPainter::Antialiasing, true);
QTransform trMillimeters = QTransform::fromScale(dpiX / 25.400, dpiY / 25.400); paint.setWorldTransform(trMillimeters, false);
paint.drawPixmap(img.rect(), img); // the problem seem to appear here
paint.end();
}
}
}```
main.cpp:
#include "wind.h"#include "wind.h"#include <QtWidgets/QApplication> int main(int argc, char *argv[]){ QApplication app(argc, argv); QMainWindow *mw = new QMainWindow(); QCoreApplication::setOrganizationName("QtExamples"); QMainWindow *mainW = new QMainWindow(); QTextCodec::setCodecForLocale(QTextCodec::codecForName("UTF-8")); wind *w = new wind(); mainW->takeCentralWidget(); mainW->setCentralWidget(w); mainW->show(); return app.exec();}
My forum topic here
