Want to have a common method to save the PNG of QMainWindow ,QGraphicsView. Qwidget

Qt Enthusiast

I went through https://forum.qt.io/topic/75776/how-to-take-snapshot-of-the-whole-gui/5

I am not able to have common methodology to save the screenshot of QMainWindow , QGraphicsView and QWidget
Can somesuggest what is common way to save the methodlogy

m.sue

You get the screenshot in form of a QImage. This you can save in multple formats (incl. PNG) with the save function: http://doc.qt.io/qt-5/qimage.html#reading-and-writing-image-files

-Michael.

Qt Enthusiast

my Question is how to get QImage from object of

QMainWindow
QWidget
QGraphicsView

m.sue

@Qt-Enthusiast

You can use one of the render functions of QWidget: http://doc.qt.io/qt-5/qwidget.html#render There you can use a QImage as QPaintDevice argument.

-Michael.

Qt Enthusiast

this is not working for QGraphicsView version 4.3.3

QPixmap * pixmap = new QPixMap(this->size())
this render(pixmap)
pixmap->save(fileName)

does not work for QGraphicsView in 4.3.3 . Could you please comment

m.sue

@Qt-Enthusiast

What does not work? What does it do that is not correct?

Qt Enthusiast

I am getting compilation error

class myView: plublic QGraphicsView {

}

no matching function call for myView::render(QPixMap* &)

m.sue

@Qt-Enthusiast

Maybe a typo: QPixMap -> QPixmap

Qt Enthusiast

no even if fix typo it is issue

Could you please try ant your end where I can common method to save snapshot of QMainWindow ,QWidget amd QGraphicsView and a sample sample code will be helpful

Qt Enthusiast

QPixmap *px = new QPixmap(this->size());
this->render(pixmap);
pixmap->save(file) not working for QGraphicsview but working for QMainWindow and QWidget

for QGraphicsView , render not found and signature should be QGraphicsView::render(QPainter

SGaist

Hi,

Do you have "#include <QPixmap>" in your .cpp file ?

Qt Enthusiast

Yes it is included

SGaist

Can you show the complete code ?

Asperamanca

@Qt-Enthusiast said in Want to have a common method to save the PNG of QMainWindow ,QGraphicsView. Qwidget:

QPixmap *px = new QPixmap(this->size());
this->render(pixmap);
pixmap->save(file) not working for QGraphicsview but working for QMainWindow and QWidget

for QGraphicsView , render not found and signature should be QGraphicsView::render(QPainter

I think this is because the render method is overloaded in QGraphicsView, but only for QPainter*, not for QPaintDevice*.

You can easily solve that problem by creating your own painter like so:

{
   QPainter painter;
   QPixmap pixmap(sizeX,sizeY);
   painter.begin(&pixmap);
   this->render(&painter);
   painter.end();
   pixmap.save(file);
}

SGaist

~~@Asperamanca the render method using QPaintDevice is inherited from QWidget so it looks like there's something else at play.~~

render is not virtual so it will be hidden by the new version of the derived class.

[edit: fixed comment SGaist]

Asperamanca

@SGaist said in Want to have a common method to save the PNG of QMainWindow ,QGraphicsView. Qwidget:

@Asperamanca the render method using QPaintDevice is inherited from QWidget so it looks like there's something else at play.

When you have two overloads of a method in the base class, and reimplement one of them in a derived class, you will (by default) no longer be able to call the other one. Unless you allow it through the 'using' keyword. I don't see QGraphicsView doing that.

SGaist

@Asperamanca absolutely correct, I've forgotten that render wasn't a virtual method.