Re: Pure Quartz vs. Cocoa-Objects ... why is Quartz slower?
Re: Pure Quartz vs. Cocoa-Objects ... why is Quartz slower?
- Subject: Re: Pure Quartz vs. Cocoa-Objects ... why is Quartz slower?
- From: Ricky Sharp <email@hidden>
- Date: Sat, 12 Feb 2005 20:22:26 -0600
On Feb 12, 2005, at 7:46 PM, Michael Becker wrote:
The one thing that I don't yet fully understand is, how iPhoto creates
this "delayed quality improvement" thing. That means, if you zoom the
images, their quality is fairly bad, but gets automatically updated
after a couple of moments.
I think just a simple timer is at work.
Consider the following case where the user clicks three times rapidly.
Each click will double the zoom factor. Rather than process each click
by doing an expensive redraw at the highest quality, a lower-quality
image is rendered. A timer is then set to fire a short time from now
(let's say 1 second)
But say the second click comes before the timer fires. The view is
redrawn with the new zoom factor, but still using the low-quality
setting. The existing timer is reset to fire one second from now.
Same goes for the third click.
Once all the clicks are done, the timer is not reset anymore and will
thus ultimately fire. At that point, the high-quality rendering can
take place.
___________________________________________________________
Ricky A. Sharp mailto:email@hidden
Instant Interactive(tm) http://www.instantinteractive.com
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