Re: handling really BIG images
Re: handling really BIG images
- Subject: Re: handling really BIG images
- From: "David Piasecki" <email@hidden>
- Date: Wed, 9 Feb 2005 09:30:41 -0800
Thanks! I didn't realize there was a performance list, but I should
have guessed!
I was considering breaking the image up into smaller images and
displaying a matrix of image tiles. I thought I heard somewhere that
it's more difficult to draw one very large image than it is to draw the
same information broken into smaller images. But that's not much in the
way of ideas.
Thanks for the advice.
David
On Feb 9, 2005, at 8:15 AM, Dave Camp wrote:
On Feb 8, 2005, at 7:09 PM, David Piasecki wrote:
I've been trying to figure out the best way to deal with displaying
really big images in Cocoa. I've got a 140MB PNG file (15k x 13k
pixels) that I want to display and move around in and zoom in and
out. The image size could be even bigger in the future. Right now I'm
using an NSScrollView which contains an NSImageView which has its
NSImage object set to my image. Scrolling around is great. Cocoa
handles the image well once it's already loaded and displayed.
However, every time I want to zoom, it takes about 10 seconds to
reload all that data. I thought setting the NSImageView to have the
option NSScaleToFit would work since I wouldn't be making a copy of
the data every time I zoom; however, I think that's what might still
be happening behind the scene since it's taking about the same amount
of time.
Perhaps I am going about this the wrong way, so I was hoping people
might have suggestions.
You might also ask this question on the performance list. I have seen
a number of good ideas posted there about dealing efficiently with
large images.
Dave
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