Sometimes when you think you’re on to something, and you end up in the flow, so bad, that it overshadows everything you’re doing. Ariya and I were working on optimizations in Graphics View and stumbled over an optimization for clipping that made a certain benchmark run 40 – forty – times faster. The patch has no known side effects, comes perfectly for free, and even opens up a couple of more optimizations we can do.
I couldn’t think of anything else on the way home from work. When I came home, I ate dinner, and immediately ran over to my home desktop, installed Git, and tried to find some way to continue where I left off.
It’s a wonderful feeling. If this patch really works this well, it’ll make it into Qt upstream, for everybody’s benefit. Mix that together with a lot of other optimization work that we’ve done, and hopefully things will truly fly.
I, for one, am looking forward to Qt 4.5 
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6 comments
*WOW*
I’m truly impressed, totally amazed, can’t wait for it to show in snapshots, can you give some more details!? =)
hey man, that’s wonderful! these are news i like to read
hehe, we’ll bug you about that at akademy
Wonderful, good work….
Yes I can imagine you could easily come up with a 40x speedup, as performance with clipping is just terrible in the current QGraphicsView… Anyway, good to know the fix is coming soon, so I can re-enable clipping and close a pending bug
I tried our application with a QT 4.5 snapshot of 20080820 and it seems to be broken.
(it works correct with QT 4.3.5)
Items are sometimes filled with the wrong colour (looks like a colour of a previous drawn item) and
also the transformation is sometimes wrong.
Is the default API changed ?
That sounds great!
Graphics View drawing optimization is really needed when it comes to drawing 100 000 of complex object drawing when points are scaled up to 10e-10( and you have to draw a polygon containing 50 000 of points).
Looking forward to Qt 4.5.
Great to hear you are working on optimization.
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