Re: CoreImage problems with very large images
Re: CoreImage problems with very large images
- Subject: Re: CoreImage problems with very large images
- From: Jim Crate <email@hidden>
- Date: Fri, 16 Nov 2007 12:11:39 -0500
On Nov 16, 2007, at 3:07 AM, Jim Crate wrote:
I'm using CoreImage in an app, but it is unusable with very large
images, e.g. a 52-megabyte 18,000 x 14,000 jpg. A 5000 x 4000 jpg
image loads and processes with great performance, but trying to
process the large image leads to very high memory use and much
swapping to disk. I tried to load the large image in the Core
Image Fun House example app, and ended up force-quitting after
waiting 10-15 minutes.
Someone suggested to try CocoaSlides, which I did, and CocoaSlides can
handle the large image in a slide show, even with a CoreImage
transition, in about 15 seconds on my MacBook Pro. This is definitely
acceptable performance, and means that I'm apparently doing something
wrong. I'll do more digging and see what I find out.
When debugging, the big hit in my app is when CoreImage is rendering
the image. Creating the CGImageRef and setting up the CIFilters takes
no time at all. I started off taking the easy way to render the image
into the NSImageView, by creating an NSImage with an NSCIImageRep, so
I'm guessing that is probably not the best way to do the rendering.
It works well for what would normally be considered large images, up
to 10000 x 8000, and didn't run into problems until hitting my largest
test images.
Thanks,
Jim
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