Re: [PATCH] ob-python: support header argument `:results file graphics'

[Ihor Radchenko <yantar92@posteo.net>]

Liu Hui <liuhui1610@gmail.com> writes:

> This patch adds graphics output support for ob-python via matplotlib.
> Specifically, it allows to use header argument `:results file
> graphics' as follows:
>
> #+begin_src python :file "test.png" :results graphics file
> import matplotlib.pyplot as plt
> plt.plot([1,2,3,4,5])
> #+end_src

This might be a useful feature, but it will break the existing
conventions, if used as in the patch. Currently, the above combination
of :file and :results is treated as the following:

‘graphics’
     When used along with ‘file’ type, the result is a link to the file
     specified in ‘:file’ header argument.  However, unlike plain ‘file’
     type, code block output is not written to the disk.  The block is
     expected to generate the file by its side-effects only, as in the
     following example:

          #+begin_src shell :results file link :file "org-mode-unicorn.svg"
            wget -c "https://orgmode.org/resources/img/org-mode-unicorn.svg"
          #+end_src

          #+RESULTS:
          [[file:org-mode-unicorn.svg]]

     If ‘:file’ header argument is omitted, interpret source block
     result as the file path.

> +try:
> +    import matplotlib.pyplot
> +    if len(matplotlib.pyplot.get_fignums()) > 0:
> +        matplotlib.pyplot.gcf().savefig('%s')
> +    else:
> +        raise RuntimeError('No figure is found. You need to use matplotlib\
> + functions, such as plot and imshow, to produce the graphics.')
> +except ModuleNotFoundError:
> +    raise RuntimeError('ob-python depends on matplotlib for saving graphics')

What if the user wants to use, for example, pyplot instead of
matplotlib?

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
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