[vtkusers] Incremental Updates

[Luis Ibanez]

Hi Ron,

I'm assuming that by 'adding' you mean something
like concatenating image regions, not cumulating
values in the same initialy defined image region.

Is that what you meant ?

If that the case, each addition to the image size
will require to re-execute the pipeline.  Note that
the pipeline is updated on demand. That is, the last
filters can trigger the execution of the first filters,
but not the other way around.

So, if your first filter is generating first a 2D image
of 10x200 pixels, then grows to 20x200, then to 30x200...
and so on, at each iteration you  have to let the last
filters know that the image size has changed and they
have to update.

This can be done at the application level by using
events and observers, but cannot be done using the
current built-in pipeline mechanisms.


Could you describe more details about the filter you
have in mind ?

It is likely that there is another way to implement it
following a more ITK-like approach.


Please let us know,


Thanks


Luis



----------------------
Ron Inbar wrote:
> Hi,
> 
>  
> 
> I have another question regarding the pipeline framework:
> 
> Suppose I have some "producer" that constantly appends data at the 
> beginning of the pipeline, without changing the data that already exist 
> there. 
> 
> So, at regular intervals I want to process the data that was added since 
> the last update, appending the result to the existing output, rather 
> than re-compute the whole output from scratch.
> 
> Can this be done using the existing infrastructure, and, if so, how?
> 
> (I'm prepared to write my own filters, if necessary.)
> 
>  
> 
> Thanks in advance,
> 
>  
> 
> Ron
> 
>  
>