Re: [Plplot-devel] plGetcursor (mouse and plplot)

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

On Tue, 25 Feb 2003 ba...@ph... wrote:

> Hi,
>
> I am thinking of converting from pgplot to plplot and I have
> a question concerning using the mouse in plplot:
>
> Namely, in Python I would like to wait for a mouse-click and get its
> coordinates. With ppgplot and the "/xwin" this works via
>         ch=pgcurs(x, y)       # wait for mouse-click
>         x,y=ch[0],ch[1]
>
> I could not find a pendant for this in plplot.
> Digging a bit it turns out that there
> is a  plGetcursor in bindings/python/plmodule.c.

I am impressed with how far you dug for this!  We have just undergone the
transition from a hand-crafted interface (plmodule.c) to a swig-generated
one.  We only keep plmodule.c around for historical reasons, but it has paid
off this time.  I had no clue that plGetcursor was in plmodule.c until you
pointed it out.

> However, in plplotcapi.i the corresponding section is commented out
> (quite at the end of the text ...).

This file together with plplotcmodule.i provides the input to swig that it
needs to generate the plplot interface.  I just tried uncommenting that
section in plplotcapi.i, and it generated a reasonable-looking interface
file that built and installed okay so I am committing the change to CVS.

I did one crude test, where this functionality seemed to work, but the
result needs further testing. Could you give that a try and let me know (off
list) how it goes?

Note, you will need swig-1.3.17.  Earlier versions won't work.

>
> This leaves me with several questions:
>   - is it save to uncomment this part and give it a try ?

Yes, with swig-1.3.17.

>   - what is the reason for excluding this routine ?

I wanted to limit the API to the so-called common API, that subset of the
public API that we make available for all interfaces.  However, that is not
a hard and fast rule, and certainly with the swig-generated interfaces it is
possible with some effort to wrap all the public API, not just the common
API subset.  Certainly if the API was available before in the old plmodule.c
it should be available in the swig-generated interface.

>   - if it works with an xwin under Linux, would it also work in
>     M$Windows ?

You should ask Olof Svensson who is in charge of that effort.

>
> Generally I think that the possibility of interactively using
> the mouse is quite important.

I agree.  Our C front end with the xwin driver has some capability in this
direction (see the locate mode in the examples/c/x01c.c example).  It should
be straightforward to generalize examples/python/xw01.py to test this xwin
driver capability in the same way.

Alan
__________________________
Alan W. Irwin
email: ir...@be...
phone: 250-727-2902

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

Programming affiliations with the Canadian Centre for Climate Modelling and
Analysis (www.cccma.bc.ec.gc.ca) and the PLplot scientific plotting software
package (plplot.org).

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