[Kde-games-devel] [Patch] Fix QPainter usage

[Ian Wadham]

On Fri, 28 Dec 2007 06:07 am, Mauricio Piacentini wrote:
> Ian Wadham wrote:
> > I am sure there were some reasons we did NOT render to QPixmaps
> > directly, to do with handling alpha (extensively used in our SVG
> > graphics) and to do with speed and fidelity of rendering (hence
> > use of QImage::Format_ARGB32_Premultiplied).
> >
> > Do you recall the details of that design decision, Mauricio?
>
> Not really, but I think it has to do with the alpha channel and
> compositing indeed. Well, Luciano can try to do something for 4.1 and
> let us know :)
>
I seem to remember hours/days I spent trying to QSvgRender direct
to QPixmaps, thinking as Luciano does to "cut out the middle man",
but I did not keep notes or commit anything.  IIRC it is easy to load
an image that already has alpha into a QPixmap, from a QImage or
from a file (.png, .jpg, .xpm, etc), but it is hard to set up an empty
pixmap of a certain size that has an alpha channel.  QPixmap is
generally poorer in methods and formats than QImage, it seems.

Well, good luck, Luciano ... Ian W.