On 2009-10-01, saulgo...@flashingtwelve.brickfilms.com 
<saulgo...@flashingtwelve.brickfilms.com> wrote:
>> Let me try to rephrase it...  Consider two scenarios (with a particular
>> OP of CHANNEL-OP-*), left one and right one:
>>
>>   save-selection + delete-selection
>>   do few FuzzySelects with OP                   do few FuzzySelects with OP
>>   combine with saved-selection with OP
>>   load saved-selection
>>
>> Is there a case when these two scenarios are going to give different
>> results?
>
> Your scenarios are identical, however, it is my opinion that more  
> useful results are produced by treating all of the Fuzzy Selects as  
> "one selection" and then combining that one selection with the  
> original selection using the OP specified (which is distinct from your  
> approach in the cases where the OP is "replace" or "intersect").

Sorry for being so obtuse, but I STILL do not see in WHAT WAY are they
"distinct" from the left scenario?

> Rendering of the projection is performed as a separate process  
> asynchronous from operations that access/manipulate the image data.  
> The projection may not even be rendered (if there is no display  
> associated with the image). It would be necessary for the  
> (hypothetical) procedure which accesses the projection to trigger a  
> re-rendering (if a "valid" one is not available) and wait for that  
> rendered projection to become valid. Once the projection becomes  
> valid, it would need to be "locked" so that other GIMP processes do  
> not modify it while the data is being retrieved -- if more than one  
> access to the projection is to be executed then the projection would  
> need to remain "locked" (effectively hanging GIMP while the script is  
> executed).
>
> It just makes much more sense to take a "snapshot" of the projection  
> at a certain point and then access that "snapshot" thereby permitting  
> other process -- including the projection rendering background process  
> -- to do their thing. For this reason (though I've explained it  
> poorly), I serious doubt you will ever see a  
> 'gimp-projection-get-pixel' type function.

Thanks a lot.  I'm sure that if such implementation details were more
documented, people would bother developers with much less
questions... :-(

> http://flashingtwelve.brickfilms.com/GIMP/Scripts/Alpha/sg-select-along-path.wrk

Thanks!
Ilya

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