Re: CGGStackRestore: gstack underflow
Re: CGGStackRestore: gstack underflow
- Subject: Re: CGGStackRestore: gstack underflow
- From: Gordon Apple <email@hidden>
- Date: Wed, 06 Aug 2008 10:49:28 -0500
- Thread-topic: CGGStackRestore: gstack underflow
I don't know anything about NSDefaultRunLoopMode and have simply been trying
to replace my layered list of draw lists with layers in what may or may not
be a scrolling view. I'm not doing anything with animation yet. To say
this has been problematic would be an understatement.
Also, in spite of much reading and many comments and responses, I have to
say that I still don't have a clue what the difference is between a layer
backed view and a layer hosted view. I assume the former is intended to be
used in the same manner as a normal view and is usually implemented by
checking the box in IB for the view, and maybe has no sublayers. Obviously,
I need sublayers. My current approach is to add a base layer to the view's
layer and then build my stack of sublayers in the base view. When using
live video, I add a QTCaptureLayer subLayer to the view's layer, but that is
not involved in the current issue. (That has its own problems, on which I
have already filed two bug reports.)
There are many things they just don't tell you in the documentation, such as
the fact that your content view's layer in a scroller will be a
CATiledLayer. I have been replacing that with my own CALayer, which could
be the source of some of the problems. (That was my attempt to go from
layer-backed to layer-hosted.)
I did once have a couple of QTCaptureViews as subviews, but not anymore. I
found out that that just didn't display properly because the capture view
apparently gets overdrawn by my layer stack. That's when I went to using a
QTCaptureLayer with z=1000 to get it out front. But that layer gets added
from my A/V controller, which hasn't happened when I'm getting all those
stack-underflow console messages.
On 8/6/08 4:41 AM, "Ryan Brown" <email@hidden> wrote:
> A shot in the dark...
>
> Are you manually activating the run loop using NSDefaultRunLoopMode? I
> recently encountered the same problem (using Core Animation as well),
> and eventually tracked it down to the way I was waiting for messages
> from a CFMessagePort to arrive. Specifying a custom run loop mode
> caused the problem to go away, and I'm still mystified as to why.
>
> If that isn't it, I'd check that you are using Core Animation
> properly. Is the NSView a layer-hosting or layer-backed view? Does it
> have any NSView subviews or CALayer sublayers? Read this if you
> haven't already:
>
> http://developer.apple.com/documentation/GraphicsImaging/Conceptual/Animation_
> Overview/ChooseAnimTech/chapter_5_section_3.html#/
> /apple_ref/doc/uid/TP40004952-CH5-SW4
>
> Best,
> Ryan
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