Re: [Plplot-devel] FW: [Plplot-general] PLPlot and FLTK driver?

[Alan W. I. <ir...@be...>]

Hi Marco:

I think switching to this list with your technical questions is a good
idea.

On 2012-01-20 20:04-0000 Quezada, Marco wrote:

> [...] Anyhow, I am glad you replied because I do have a decision to
make regarding our application. It is currently written in fltk and
I'd like to embed some plots into it. But the gui portion is not large
so it is a balance between writing the fltk driver and switching our
gui into qt and using that driver. I have to check with the team
before I make the call. I also was wondering if the mem driver might
work as an initial proof of concept for us. It seems using that driver
we can obtain an image that can then be rendered by any gui toolkit
that can handle displaying pictures. Is this correct? I am basing this
only on browsing through the code because I could not find examples
besides the one written in python.

I am a bit prejudiced against the mem driver because of that lack of
examples.  That might be a warning that it is not suitable for your
proof of concept.  But someone else more familiar with that driver
should comment on that question.

> I did look through the qt driver thinking the same thing, that this
would be the template we could use to write the fltk driver. It seems
the driver is just an interface that matches Plplot's api with the GUI
toolkit's so that input or expose events in the gui can be sent and
handled by PlPlot and then drawing events are passed to the gui along
with the data in order to manipulate the image. Am I close on this?

Our normal interactive use case is an application written in one of
our supported languages calls the PLplot library which in turns
dynamically loads the interactive device driver specified by the user
which then renders the specified plot.  IOW, our interactive devices
are often used just like our non-interactive file-generating plot
devices. However, for some device drivers such as qt, alternative use
cases are available so that PLplot can be embedded in a GUI.  For a
simple example of this idea with qt, have a look at 
examples/c++/README.qt_example and build and test that described
example.  I have just brought the build and test instruction part of
that file up to date with revision 12138 of our svn trunk version of
PLplot.

> We do have other applications already using fltk and although I am
not necessarily a fan of it, I don't see us switching any time soon.
So with time it might be possible for myself or my team to write a
driver for it. No promises but if we do we'll let you know.

I am told, although I haven't actually done it myself, that writing a
device driver for PLplot is straightforward.  To give you some idea of
the effort involved, our qt device driver was contributed by a
professional developer working for the external QSAS team who IIRC
wrote the first version in a week or so. That worked, but it only had
Hershey fonts and other constraints so then he rewrote it almost
completely from scratch with all the bells and whistles.  I think that
took the order of an additional month or two.  So you can develop a
proof-of-concept driver in a relatively short amount of time, but to
do a really good job takes a lot longer.  Of course, that is true of
all software development.  :-)

Alan
__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
__________________________

Linux-powered Science
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