How to sendEvent QPaintEvent ?

[SABROG]

I want redraw one widget without hi's childs, how to use QProcess::sendEvent with QPaintEvent ? I try this, but this doesn't work:

QPaintEvent *pe = new QPaintEvent(ui->groupBox->rect());
    ui->groupBox->setAttribute(Qt::WA_WState_InPaintEvent, true);
    QApplication::sendEvent(ui->groupBox, pe);
    ui->groupBox->setAttribute(Qt::WA_WState_InPaintEvent, false);

QPaintEvent *pe = new QPaintEvent(ui->groupBox->rect());
    ui->groupBox->setAttribute(Qt::WA_WState_InPaintEvent, true);
    QApplication::sendEvent(ui->groupBox, pe);
    ui->groupBox->setAttribute(Qt::WA_WState_InPaintEvent, false);

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But this code work and i dont' undrestand why:

QPaintEvent *pe = new QPaintEvent(ui->groupBox->rect());
    QPixmap pix(ui->groupBox->size());
    pix.fill(Qt::white);
    QPainter::setRedirected(ui->groupBox, &pix);
    QApplication::sendEvent(centralWidget(), pe);
    QPainter::restoreRedirected(ui->groupBox);
    pix.save("file.jpg");

QPaintEvent *pe = new QPaintEvent(ui->groupBox->rect());
    QPixmap pix(ui->groupBox->size());
    pix.fill(Qt::white);
    QPainter::setRedirected(ui->groupBox, &pix);
    QApplication::sendEvent(centralWidget(), pe);
    QPainter::restoreRedirected(ui->groupBox);
    pix.save("file.jpg");

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[wysota]

What's wrong with calling repaint() or update? The children should be taken from the backing store if they didn't change and their background didn't change.

[SABROG]

What's wrong with calling repaint() or update? The children should be taken from the backing store if they didn't change and their background didn't change.

I want prevent childrens repaint for overpainting from parent widget. I want change order for repaint recursion. Parent must be last.

[wysota]

But this will make it paint over the children so you would see nothing. If you really want that have an overlay widget that is transparent and uses QWidget::render() to retrieve a pixmap of the parent and use drawPixmap to paint it on itself.

[SABROG]

We found other solution.


installEventFilter for all childs, QApplication::sendEvent in QEvent::Paint for each child.

[aamer4yu]

From the above pic, how do u expect to work with the combo box ?
Also the hip hop screen looks more like a splash screen

[SABROG]

From the above pic, how do u expect to work with the combo box ?
Also the hip hop screen looks more like a splash screen

Combobox and etc will be over picture, this is true. But i thing this not really matter

Also the hip hop screen looks more like a splash screen

Only "looks like", this overpaint for each child.

[wysota]

Using an overlay this would have been much simpler and quicker in terms of performance

[wiki]Widget Overlay[/wiki]

[SABROG]

Using an overlay this would have been much simpler and quicker in terms of performance

[wiki]Widget Overlay[/wiki]

I read this page before, but for academic interest i want use only paint features, without any additional widgets. And, unfortunately, i found some things that Qt can't do.
It would be very nice if the QtSoftware will make an additional functionality for such things.

[wysota]

And, unfortunately, i found some things that Qt can't do.

Ok, such as?

[SABROG]

Ok, such as?

Like painting over widgets without additional widget and hemorroid with installEventFilter and reimplement paintEvent for all childs. Like create semi-transparent main widget with system titlebar or just titlebar paint from Qt (semi-transparent widget without flag Qt::FramelessWindowHint).

---
More experiments...

[wysota]

Like painting over widgets without additional widget and hemorroid with installEventFilter and reimplement paintEvent for all childs.

I'm sure you'll admit this is not what normally people do :-)

By the way, look here: http://www.qtcentre.org/forum/showth...ht=post+filter

Like create semi-transparent main widget with system titlebar or just titlebar paint from Qt (semi-transparent widget without flag Qt::FramelessWindowHint).

And here: Creating Translucent Windows. For the title bar blame your system - it is not part of the application so it has no control over it.

Any other requests? :-)

[SABROG]

I'm sure you'll admit this is not what normally people do :-)

By the way, look here: http://www.qtcentre.org/forum/showth...ht=post+filter

Thanks for link, this what we actually doing, but with call QApplication::sendEvent again.

And here: Creating Translucent Windows. For the title bar blame your system - it is not part of the application so it has no control over it.

Any other requests? :-)

With system titelbar i understand. Qt cat draw titlebar from code in QGraphicsWidget for QGraphicsScene. But simple users can't call this painter for Translucent Windows and must write own implementation for this.

--Updated--
I post our solution on wiki.crossplatform.ru