qwidget.render drawing with offset in QStyledItemDelegate

Question

I'm trying to create a delegate to draw custom widgets as elements in a listview on icon mode. I have it more or less working but I can't get the widgets to draw in the right place, it seems they are getting drawn considering (0,0) the origin on the main window not the origin of the list view. What do I need to pass to render the widget on the right place? I know I can pass an offset... how can I calculate the offset between the main window and the listview?

This is my paint method on my delegate (derived from QStyledItemDelegate)

def paint(self, painter, option, index):

        painter.save()

        if option.state & QStyle.State_Selected:
            painter.fillRect(option.rect, option.palette.highlight());

        model = index.model()
        myWidget = model.listdata[index.row()]


        myWidget.setGeometry(option.rect)

        myWidget.render(painter, option.rect.topLeft() )

        painter.restore()

Thanks

/J

Answer 1

In case this is useful for someone else I'll post my solution...

I don't know if this is the best way of doing it, but I'm calculating the offset by mapping the orgin of my parent to the main window:

offset = self._parent.mapTo(self._mainWindow, QPoint(0,0))
myWidget.render(painter, option.rect.topLeft() + offset)

It works, so I'll use it until I find a better way for doing this.

Answer 2

You can render your Widget into a temporary pixmap and then draw the pixmap instead. That solves the shift issue:

def paint(self, painter, option, index):
        pic = QPixmap( option.rect.width(), option.rect.height() )
        w = ItemWidget()
        w.setGeometry( option.rect )
        w.render(pic)            
        painter.drawPixmap( option.rect, pic )