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: Chilton Webb <email@hidden>
- Date: Sat, 12 Feb 2005 20:59:13 -0600
Hi Michael,
On Feb 12, 2005, at 7:46 PM, Michael Becker wrote:
My idea now is to specify certain thresholds where the images get
recached in different sizes. So if you zoom them smaller than 100
pixels wide, the image gets recached in a 40 pixels wide format... I
am not sure.
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 it's an old trick (one I'm using, and I ain't smart enough to
make this stuff up).
One thread displays data stored in a buffer, another reads from the
files and generates the thumbnails. If you've noticed, iPhoto stores
multiple copies of each image. One is a thumbnail, which it reads in at
low res, then goes back for a second pass to fill in the gaps.
Meanwhile the first thread displays the low res images stretched out,
and as the second thread reads in the file with more detail, it
displays it.
Of course, that's just my assumption. In this case, my image display
mechanism is in Carbon, and it's as fast as iPhoto, so I assume
something similar is being done.
-Chilton
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Cocoa-dev mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden