[Insight-users] Pipeline and ReleaseDataFlagOn().

[Miller, James V (Research)]

When you call ReleaseDataFlagOn() on a filter, it sets a flag
on the filter's OUTPUT that the data is to be release when requested.

The filter finishes executing, it runs through its INPUTS and 
checks if to see if any of the inputs are marked for release. If they
are marked, the bulk data (pixel data) is freed.

In your example, there is no filter after the RegionOfInterestFilter, 
so its OUTPUT will be available.  This image is still marked for
release, so if you later pass it to another filter, that filter 
will free that memory.

A reasonable practise is to call ReleaseDataFlagOn() on all your
filters EXCEPT the last one.

Jim



-----Original Message-----
From: insight-users-bounces+millerjv=crd.ge.com at itk.org
[mailto:insight-users-bounces+millerjv=crd.ge.com at itk.org]On Behalf Of
Michal Postrozny
Sent: Monday, June 06, 2005 5:48 AM
To: insight-users at itk.org
Subject: [Insight-users] Pipeline and ReleaseDataFlagOn().


Hello,

I have a question regarding releasing filter data in pipeline.

Let's have a pipeline like this:

ImageFileReader -> RegionOfInterestImageFilter -> my_Image

If I set:

ImageFileReader->ReleaseDataFlagOn();
RegionOfInterestImageFilter->ReleaseDataFlagOn();

I assume that after calling

RegionOfInterestImageFilter->Update()

my_Image is not pointing to any data, so calling any filter with
my_Image as input parameter will casue an exception.

Is this true or am I completely wrong?


Thanks in advance

Michal Postrozny



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