Re: Threaded drawing - JPEG
Re: Threaded drawing - JPEG
- Subject: Re: Threaded drawing - JPEG
- From: Steve Sisak <email@hidden>
- Date: Wed, 11 Dec 2013 12:53:10 -0500
At 10:25 AM -0800 12/10/13, Seth Willits wrote:
On Dec 10, 2013, at 1:32 AM, Graham Cox <email@hidden> wrote:
> But my situation is that I need to draw VECTOR objects up to
25,000% zoom with no pixelization.
You're given a CGContext to draw into; What's the difference? The
tiled drawing is async, so if the drawing doesn't occur fast enough
it'll scale up the low-scale bitmap, but what's evil about that?
It's like Apple or Google maps.
Not to hijack the thread, but I'm just getting head into optimizing
some code which displays live preview for a number of JPEG streams
simultaneously.
Most implementations I've tried result in being CPU bound in JPEG
code on the main thread with the 7 other cores idle.
I've tried variants of NSImageView, CGImage and CIImage and all
that's needed to render them on alternate threads but Cocoa appears
to so good at delaying evaluation as long as possible that it seems
to end up calling the JPEG decoder synchronously from -drawRect of
whatever view subclass I've chosen on the main thread.
Any suggestions for what technologies to use to run a JPEG through,
say CIImage w/o blocking the main thread.
This has turned out to be way more complicated than I thought.
Thanks,
-Steve
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