matplotlib-devel Mailing List for matplotlib

>>>>> "Jochen" == Jochen Voss <vo...@se...> writes:

    Jochen> Hello, why is figure derived from the Artist class?  This
    Jochen> causes some special casing (figure is the only artist
    Jochen> where artist.figure does not point to the figure).

    Jochen> The the figure actually used as an Artist somewhere?  What
    Jochen> would break if it would not be derived from Artist?

In a couple of places - in the call to set_transform in
Figure._set_artist_props and when FigureCanvas calls
figure.draw(renderer).  One could write a figure class that was not
derived form Artist, but I don't really see the benefit of changing
it.  The Artist hierarchy are basically all the things that implement
draw(renderer).  Of course in a dynamically typed language one doesn't
need to derive from Artist to implement draw(renderer), but it seems
conceptually cleaner to do so in this case -- plus I have already done
the Artist hierarchy in graphviz and included it in the users guide
:-)

It might also break some code which is relying on the Artist methods,
eg fig.get_transform (for people who want to add lines, text, etc in
fig coords).  I doubt there are many such people, but it is a
possibility.

    Jochen> I tried the patch

I didn't test this - did it pass backend_driver?

JDH

On Wed, 2004-11-03 at 12:48,
mat...@li... wrote:
> Message: 1
> Date: Tue, 2 Nov 2004 17:34:00 +0000
> From: Jochen Voss <vo...@se...>
> To: mat...@li...
> Subject: Re: [matplotlib-devel] questions about the PS backend
> 
> 
> --ZPt4rx8FFjLCG7dd
> Content-Type: text/plain; charset=us-ascii
> Content-Disposition: inline
> Content-Transfer-Encoding: quoted-printable
> 
> Hello,
> 
> On Sun, Oct 31, 2004 at 10:33:27AM -0600, John Hunter wrote:
> >     >> 7) The template backend uses=3D20
> >     >>=20
> >     >> verbose.report('Error: %s'%msg)
> >     >>=20
> >     >> Should this be 'verbose.report_error' instead?
> >=20
> > Yes.
> >=20
> >     Steve> No verbose() at all! But I agree I think it should be
> >     Steve> 'verbose.report_error'
> >=20
> > Yes, it should.  All printing should either go to verbose.report or
> > verbose.report_error, so that the user specified output handles are
> > used.  This was just an oversight in backend_bases.error_msg.
> > Everyone should feel free to fix these as they find them.
> Then the recent change to error_msg_template should be reverted,
> shouldn't it?
> 
> All the best,
> Jochen
I had the problem of error_msg() being called, executing
verbose.report('Error: %s'%msg) and no message being reported. I checked
how backend_agg handles errors and deleted verbose.report() and updated
the doc string to be consistent with the way agg uses error_msg().

We now have 'verbose' and error_msg() which both report errors. The
difference is that error_msg() has the side-effect of terminating your
program, which is not necessarily what you expect from its name.
I'd prefer to delete error_msg() completely, use 'verbose' for all
errors and add a 'raise SystemExit()' after it if you need to terminate
the program. I think it would make the code easier to understand.

Steve