[Kst] branches/work/kst/kst1kde4/kst/src/libkst

[Peter Kümmel]

Am Donnerstag, den 26.11.2009, 18:46 -0500 schrieb Barth Netterfield:
> On Thursday 26 November 2009 18:26:39 Peter Kuemmel wrote:
> > > This is a user preference question: do I want to be able to delete a
> > > vector and everything it depends on from the data manager, or do I have
> > > to start at
> > > the top of the tree, eg,  remove the curve from the plot, delete the
> > > curve,
> > > then delete the vector...  1.x had a 'purge' button which would
> > > repeatedly delete all unused object until everthing that was unused was
> > > gone to make this more convenient.  That being said, I tend to agree we
> > > should go back to the 1.x way.
> > 
> > I don't know the data manager. Is it like a vector paint program? Then why
> >  not simply delete only marked objects?
> 
> kst has a hierarchy of objects: 
> 
> DataSources (ie, files)
> Primitives (vectors, scalars, strings, matrixes): can depend on DataSources, 
> or on DataObjects.
> Data objects : inputs are primitives, outputs are primitives (eg, equations, 
> spectra)
> Relations: inputs are primitives, can be rendered (ie, images and curves).
> 
> ViewItems: draw to the screen; can depend on relations (ie, plots) or 
> primitives (ie, labels can depend on strings and scalars)
> 
> The data manager lists all of the objects which have been created, and some 
> info about each one.  From the data manager, one can delete or edit the 
> objects.
> 
> The question is: should you be able to select and delete, eg, a vector, which 
> is currently used by a curve which is in a plot (in which case, perhaps, the 
> curve would be removed from the plot and deleted before the vector was 
> deleted) or should this be impossible until the curve was removed from the 
> plot and then deleted (or its inputs changed to something else).

Sound like a model-view problem: the curve is the view of the vector.
And in principle the curve would also disappear when the vector is
deleted, and the curve could be deleted (disabling view) without
removing the vector. But removing the vector without also removing
the curve would break the mv-pattern. Are there reasons to do this
(low memory), or is it even the standard way of using kst?

Peter