Re: Thread safe?
Re: Thread safe?
- Subject: Re: Thread safe?
- From: "Adam R. Maxwell" <email@hidden>
- Date: Sun, 30 Mar 2008 08:01:16 -0700
On Mar 30, 2008, at 6:10 AM, Thomas Engelmeier wrote:
On 29.03.2008, at 18:54, Adam R. Maxwell wrote:
Drawing into an NSImage is explicitly documented to be thread safe
in the article you linked to, and each thread has its own graphics
context. The post I linked to does indicate that you might want to
use [image setCacheMode:NSImageCacheNever]. If your goal is just
to get an NSBitmapImageRep from a file, it's probably easier just
to use +imageRepWithContentsOfFile:.
While it is documented to be thread save you might get crashes later
when an NSBitmapImageRep created by drawing into from an secondary
thread gets drawn itself. The crash occurs when the image tries to
access an NULL (offscreen) window context (it probably was
originally drawn into).
Tried to debug that on 10.5.2 (and simply worked around)...
That's interesting. Was it an NSBitmapImageRep or NSImage/
NSCachedImageRep? I didn't think a bitmap context would be associated
with a window context like that. Either way it doesn't sound good,
though.
--
adam
On Mar 30, 2008, at 6:10 AM, Thomas Engelmeier wrote:
On 29.03.2008, at 18:54, Adam R. Maxwell wrote:
Drawing into an NSImage is explicitly documented to be thread safe
in the article you linked to, and each thread has its own graphics
context. The post I linked to does indicate that you might want to
use [image setCacheMode:NSImageCacheNever]. If your goal is just
to get an NSBitmapImageRep from a file, it's probably easier just
to use +imageRepWithContentsOfFile:.
While it is documented to be thread save you might get crashes later
when an NSBitmapImageRep created by drawing into from an secondary
thread gets drawn itself. The crash occurs when the image tries to
access an NULL (offscreen) window context (it probably was
originally drawn into).
Tried to debug that on 10.5.2 (and simply worked around)...
That's interesting. Was it an NSBitmapImageRep or NSImage/
NSCachedImageRep? I didn't think a bitmap context would be associated
with a window context like that. Either way it doesn't sound good,
though.
--
adam
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