Printing Widgets: Why are they rendered into Pixmap / Bitmap?

[Mr.Green]

Hi all.
my Question is very similar to this one (http://www.qtcentre.org/threads/4334...pixmap-backing) which hasn't been answered.

How do I print Widgets "in the right way"?
I've got a bunch of Widgets in a Layout that I want to be printed out.

My idea was:

auto printer = new QPrinter(QPrinter::ScreenResolution);
...
 
QPainter painter;
painter.begin(printer);
 
//Scale to Page Size
double xscale = printer->pageRect().width() / double(m_current_page->page->width());
double yscale = printer->pageRect().height() / double(m_current_page->page->height());
painter.scale(xscale, yscale);
 
content->render(&painter, QPoint(), QRegion(), QWidget::DrawChildren);   //I've also simply using content->render(&painter);

auto printer = new QPrinter(QPrinter::ScreenResolution);
...

QPainter painter;
painter.begin(printer);

//Scale to Page Size
double xscale = printer->pageRect().width() / double(m_current_page->page->width());
double yscale = printer->pageRect().height() / double(m_current_page->page->height());
painter.scale(xscale, yscale);

content->render(&painter, QPoint(), QRegion(), QWidget::DrawChildren);   //I've also simply using content->render(&painter);

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This seemed to be very easy, but the problem now is:
I may choose between Highresolution and slow printing and big Filesize (when printing to a PDF).
Or: bad Resolution.

My question is: Why does Qt print by rasterizing the whole Widgets (including their Labels etc). into Pixmaps?
And what can I do against that?

Or am I completely wrong when trying to print them this way?

Thanks.
Mr.Green

[wysota]

Why does Qt print by rasterizing the whole Widgets (including their Labels etc). into Pixmaps?

Because widgets are drawn using raster graphics.

And what can I do against that?

Don't print widgets. Print vector graphics and text.

[Mr.Green]

So that means I would have to re-invent the layouting System...?

[wysota]

I have no idea why you want to print widgets so I cannot answer your question. Usually you'd be printing documents and not widgets.