Re: [Plplot-devel] Thoughts from the release guy

[Maurice L. <mj...@ga...>]

Maurice LeBrun writes:
 > Alan W. Irwin writes:
 >  > (5) There is still one issue holding back Olof et al from moving to our
 >  > supported python interface for their pyqt GUI work. They require two output
 >  > devices (one for the GUI and one to store results more permanently).  I just
 >  > checked that this was possible with -dev tk.  I haven't looked at the
 >  > plframe code that implements this functionality, but I speculate separate
 >  > devices are opened for two different streams. I have classified this one as
 >  > "Major, would be nice", but in fact a simple solution following what is done
 >  > for -dev tk might be possible in which case this should be reclassified as
 >  > minor, "would be nice"
 > 
 > I assume you're referring to "the normal plmkstrm/plcpstrm/plreplot/plend1 way
 > of saving plots".  Is this kind of stream duplication via API sufficient for
 > their needs?  
 > 
 > Because otherwise one could clone a stream at the driver interface layer,
 > directing it somewhere else (e.g. a file).  I thought about putting in
 > something like this years ago but didn't have a real need for it so it never
 > materialized.  

After rereading this, I thought this might have been a bit too obscure.

The way of saving the current plot mentioned in my first paragraph is atomic,
one that you use at the end of a page i.e. "save this page".  So it arose in
association with the extended plframe for its "save" or "print" commands.
It has several problems:
 - only done at end of page
 - API or GUI driven -- not automatic
 - how to deal with end of page -- new file or same file?

The cloned stream approach would associate one stream with another, such that
every driver interface call to the original stream would go to the cloned
stream as well.  The appeal of this approach is that it would be virtually
continuous, automatic, and you'd have all the standard plplot calls on the
cloned stream.  It'd also be easy (and fun) to test with the interactive
drivers -- you'd just get multiple windows up on the screen, all displaying
(theoretically) the same thing.

-- 
Maurice LeBrun    mj...@ga...
Research Organization for Information Science and Technology of Japan (RIST)