id,node_id,number,title,user,state,locked,assignee,milestone,comments,created_at,updated_at,closed_at,author_association,active_lock_reason,draft,pull_request,body,reactions,performed_via_github_app,state_reason,repo,type
404945709,MDExOlB1bGxSZXF1ZXN0MjQ5MDE0MTc3,2729,[WIP] Feature: Animated 1D plots,35968931,closed,0,,,14,2019-01-30T20:15:52Z,2021-06-24T08:46:31Z,2021-06-23T16:14:28Z,MEMBER,,0,pydata/xarray/pulls/2729,"This is an attempt at a proof-of-principle for making animated plots in the way I suggested in #2355. (Also relevant for #2030.)

This example code:
```python
import matplotlib.pyplot as plt
import xarray as xr

# Load data as done in plotting tutorial
airtemps = xr.tutorial.open_dataset('air_temperature')
air = airtemps.air - 273.15
air.attrs = airtemps.air.attrs
air.attrs['units'] = 'deg C'

# Downsample to make reasonably-sized gif
data = air.isel(lat=10, time=slice(None,None,40))

# Create animated plot
anim = data.plot(animate_over='time')
anim.save('line1.gif', writer='imagemagick')
plt.show()
```
now produces this gif:
![line1](https://user-images.githubusercontent.com/35968931/56898342-b833a680-6a88-11e9-9529-ca8584943d0f.gif)
~~The units on the timeline are formatted incorrectly because [this PR](https://github.com/t-makaro/animatplot/pull/21) isn't merged yet~~

I think it looks pretty good! It even animates the title properly. The actual animation creation only takes one line to do.

This currently only works for a plot with a single line, which is animated over a coordinate dimension.
~~It also required some minor modifications/bugfixes to animatplot, so it probably isn't reproducible right out of the box yet.~~ If you want to try this out then use the [develop branch](https://github.com/TomNicholas/animatplot/tree/develop) of my forked version of animatplot.

The reason I've put this up is because I wanted to

1. show people the level of complexity required, and 
2. get people's opinion on the implementation. 

I feel like although it required only ~100 lines extra to do this then the logic is very fragmented and scattered through the `plot.line` and `plot._infer_line_data` functions. In 2D this would get even more complicated, but I can't see a good way to abstract the case of animation out?

(@t-makaro I expect you will be interested in this)

EDIT: To-Do list:

- [x] Animate single line
- [x] Animated line and static line on same axes
- [x] Animate multiple lines on same axes
- [x] Multiple animated line plots on same figure
- [ ] ~~FacetGrids of multiple animated lines~~ (will leave for a later PR)
- [ ] Complete set of tests
- [x] Add animatplot as optional dependency
- [x] Add new CI tests using animatplot
- [ ] New documentation page
- [x] Fix issues with formatting of timeline label (fixed by https://github.com/t-makaro/animatplot/pull/46)","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/2729/reactions"", ""total_count"": 2, ""+1"": 2, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,,13221727,pull