[Qgis-developer] QGIS Processing Framework

[Camilo Polymeris]

On Fri, Jul 8, 2011 at 1:46 AM, MALIK Julien <julien.malik at c-s.fr> wrote:
> Hello Camilo,
>
> Some feedback about your todo list :
>
> - constraints and validator is low priority to me : it can be handled by the
> underlying implementation for now
> - user level is low priority to me as it will probably be easy to add this
> feature later when the big things will be in shape

Ok.

> - interactive parameters : higher priority to me. Having a way for the
> implementation to tell the GUI "update every widgets". Maybe I already have
> a way to do that (?)

There is already a way to do that: Have your module instance signal
"parametersChanged" (for changes in parameter structure/multiple
values or "valueChanged" for changes in single values). Haven't tested
it yet, though.

By interactive I mean stuff like selecting regions in canvas, single
features, etc.

> A few things you don't mention :
> - running the processing modules programmatically

Related to chaining & serialization. (Want to serialize in python commands).

> - progress reporting
> - logging
> - multiple values parameter type (at least to provide a "multiple input
> layers" parameter type)

Ok.

> - parameter groups (what happen currently with the SAGA "nodes" ?)

Yes that was missing from the list: Nodes are ignored and everything
presented flat. The ParameterList structure was intended to provide
that functionality, but isn't implemented yet.

>
> I agree with your analysis : being able to access the QGis layers for the
> input/output is now the most important thing to focus on.
>
> What precisely is blocking you on this topic ?
> I saw some recent updates adding a combobox with the layers but did not test
> it yet. The implementations could handle the conversion into their own
> internal data structure from the MapLayer objects.
> I know at least that on the OTB side, a first step will be getting a
> gdal/ogr compatible dataset name and pass them as input files to the
> implementation.
> As I can remember, SAGA has a "gdal/ogr" importer module for inputs, and the
> output should be simple also as the saga file format is supported by gdal.

Thanks for your comments. The I/O thing is more of a saga-specific
issue, I am not sure where & in which format to exchange data.. but
these comments are helping clarify matters.

Camilo