error message although writer library is installed

[manfred2020]

hello, i wanted to try your interesting library, but i always get an error (animated figure does not show up on screen and i also cannot save figure as gif).

errors (when trying to save figure):

with version 0.1.13 i get "RuntimeError: Ensure that a matplotlib writer library is installed, see https://github.com/JackMcKew/pandas_alive/blob/master/README.md#requirements for more details".

with version 0.1.12 i got "'MovieWriterRegistry' object is not an iterator".

im running pandas-alive on windows 10, python 3.7.7, matplotlib 3.2.1, pandas 1.0.3, Pillow 7.1.2.

[JackMcKew]

Hi!

Thank you for raising this.

Currently Pandas-Alive only supports writing to a GIF via imagemagick.

It's in the to-do list to investigate if Pillow will work for GIFs as well.

[JackMcKew]

I cannot get Pillow to generate GIFs.

It just returns Index Error: list index out of range whenever I try to invoke anim.save(filename,writer=Pillow) or anim.save(filename,writer=PillowWriter())

PRs are most definitely welcome if you can make this work, otherwise I have altered Pandas_Alive to state that Pillow is not supported.

In preparation for the next release, you will be able to define your own custom writer.

[manfred2020]

thanks for the fast reply!

so right now out of these

"Ensure to have one of the supported tooling software installed prior to use!

ffmpeg
ImageMagick
Pillow"

only imagmagick works? or can i save the animated figure with another file format (not gif) when using pillow?

[JackMcKew]

Great question!

I'd been planning a new release to make sure that Pillow was explicitly unsupported after my experience yesterday, but I did only try producing GIFs. I'll see if any other file type works first.

[JackMcKew]

Pillow doesn't seem to play nice whatever the file type is.

For future readers the error that is being raised each time the Pillow library is specified is:

Exception has occurred: IndexError
list index out of range
  File "C:\Users\jackm\Documents\GitHub\pandas-alive\pandas_alive\_base_chart.py", line 555, in save
    anim.save(filename, fps=self.fps, dpi=self.dpi,writer=self.writer)
  File "C:\Users\jackm\Documents\GitHub\pandas-alive\pandas_alive\plotting.py", line 339, in plot
    line_race.save(verify_filename(filename))
  File "C:\Users\jackm\Documents\GitHub\pandas-alive\playground.py", line 12, in <module>
    covid_df.sum(axis=1).fillna(0).plot_animated(filename='test.mp4',kind='line',period_label={'x':0.1,'y':0.9},enable_progress_bar=True,writer="pillow")