[Okular-devel] Bring pixmaps back!

[Albert Astals Cid]

Well, today i've been profiling a bit okular and discovered we are taking a 
BIG hit for using QImages instead of QPixmaps, i knew there was a hit, but 
this is huge (below for numbers).

So Tobias can we bring back Pixmaps? AFAIK they were removed to speedup 
rotation that required pixmap->image->pixmap, but i prefer to take a hit when 
rotating than when navigating the document.

Now the numbers:

92.69% of paintPageOnPainter gets spent on destPainter->drawImage
99.99% of QPainter::drawImage is spent on a different drawImage
99.99% of QPainter::drawImage is spent on a different drawImage
99.12% of QPainter::drawImage is spent on QX11PaintEngine::drawImage
99.99% of QX11PaintEngine::drawImage is spent on QPaintEngine::drawImage

87.20% of QPaintEngine::drawImage is spent on QPixmap::fromImage
12.57% of QPaintEngine::drawImage is spent on QImage::copy
00.04% of QPaintEngine::drawImage is spent on QX11PaintEngine::drawPixmap

So basically if we keep pixmaps and not images we for sure remove the 87.20% 
of QPixmap::fromImage

Albert