Re: QTMovieLayer and renderInContext:

FROM : John Clayton
DATE : Thu Nov 22 10:07:50 2007

:-)

Scott, I guess you *may* have seen my DTS support request for 
CARenderer then? (I think it *is* very convoluted code [that I have], 
I cant get the thing to go, its all new to me - but I'm willing to 
learn).

I will file a bug report for this then, I have a spike/test solution 
that demonstrates clearly that the rendering fails for a QTMovieLayer 
that is calling renderInContext:

I guess I can fire you the question thats been hanging around in my 
head since day 1 then (about 8 months ago actually).  Q is this:  how 
would I use core-anim to render any CALayer tree onto a view, but only 
at a particular time (i.e. 2.6 seconds) and also make use of all the 
transitions and animations and so on [that core anim is good at 
doing]?  E.g. I have a complex CALayer and one of the contained layers 
has an animation at 2 seconds for a duration of 5 seconds that fades 
that layer out. (think: layers as movie timelines and using a slider 
to scrub back and forth in time).

I've tried *a lot* of ways, and the basic problem appears to be 
telling layers that they should indeed render for time 't', regardless 
of what the CACurrentMediaTime() and underlying core-anim time-line is.

Anyways, I'll file a bug report along with my spike solution and let 
you know its ID.

--
John Clayton

On Nov 22, 2007, at 9:48 AM, Scott Anguish wrote:

>
> On Nov 22, 2007, at 3:22 AM, John Clayton wrote:
>

>> I'm not, that renderInContext: is a call on CALayer, allowing one 
>> to place the content of a layer into a CGContextRef
>>

>
> Gah, sorry.  I miss read the original email. I should have 
> recognized the method, I wrote the reference doc for it.
>
>

>> The CovertFlow example uses this technique to take content into a 
>> bitmap based context.

>
> Wow, it does.  but I wonder why.  It's just creating a bitmap with a 
> string in it.
>
> I'm not sure whose example that is, but I've asked engineering.
>
> If you determine that QTMovieLayer isn't rendering using that 
> method, please file a bug and let me know.
>
>

>> I've got requirements to basically render arbitrarily complex 
>> CALayer hierarchies onto a view, but I want to render them for a 
>> particular time.
>>
>> What is CARenderer intended for then?  (I've used CARenderer in 
>> another different spike/test solution so have experience with it).
>>

>
> Yes, that would be a CARenderer situation. I've only seen one 
> example of it in use and it was, shall we say, convoluted.
>

>> Thanks.
>>
>> --
>> John Clayton
>> http://www.coderage-software.com/
>>
>>
>>
>> On Nov 22, 2007, at 9:11 AM, Scott Anguish wrote:
>>

>>> I'm not sure of the answer..
>>>
>>> but why are you using CARenderer to put movie content into a view?
>>>
>>> it shouldn't be used for display purposes.
>>>
>>>
>>> On Nov 22, 2007, at 1:47 AM, John Clayton wrote:
>>>

>>>> Hi All,
>>>>
>>>> I am trying to use the CALayer renderInContext: call to put the 
>>>> contents of a QTMovieLayer instance onto a view, but I get a 
>>>> blank view - nothing renders.
>>>>
>>>> Is this call supposed to work for a QTMovieLayer?  I suppose the 
>>>> question could be expanded to: is the renderInContext: method 
>>>> supposed to work for any type of open-gl based layer class?
>>>>
>>>> Thanks,
>>>> --
>>>> John Clayton
>>>> http://www.coderage-software.com/
>>>>
>>>>
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>>>

>>

>