[Matplotlib-users] using draw_if_interactive in library plots?

[Skipper S. <jss...@gm...>]

Hi All,

Hoping someone can help me get a definitive answer to this question.
Is draw_if_interactive bad to have in library plotting code?

Based on this thread [1], we've been working under the assumption that
calling draw_if_interactive in plotting code is bad. Though I'm
skeptical that this is the takeaway that we should have. I also asked
this question on the IPython mailing list [2] since the recommendation
comes from their type of usage, but I'm still not clear.

I'll repeat the gist of the question here.

We have plotting functions that are designed to update a given axes. I
often work in interactive mode, and I'd like it if these functions
updated my axes in the way that I expect (and an R user doing plotting
in Python would expect). But now I'm forced to litter my user scripts
with draw_if_interactive after I call a function I expect to update a
plot - say updating a scatter plot with a regression line. Would be
harmful to just include these draw_if_interactive calls in our plot
functions. To be clear, I never have to call show or draw because I'm
working in interactive mode, so the recommendation to just call show()
at the end of a script is not what I want.

My understanding of the pitfalls is 1) there's a performance hit to
calling draw instead of just making one call. This is moot because
we're only calling draw_if_interactive - so we assume the user is
working interactively and actually wants to do the drawing and doesn't
care about the performance hit. And 2) we are assuming that the user
has imported and is using pyplot and there are possible side effects.
A user wouldn't be using pyplot in a GUI or in some sort of embedded
plotting framework. However, my intuition says that if this is the
case, draw_if_interactive won't do anything because interactive will
be False in these cases.

Can someone please help clear this up? Thanks,

Skipper


[1] https://groups.google.com/forum/#!msg/pystatsmodels/biNlCvJPNNY/BT7bQJmOa1cJ
[2] http://python.6.n6.nabble.com/IPython-User-using-matplotlib-draw-if-interactive-in-library-code-td4991275.html