[FEATURE] Axis break symbols

[nickhenden]

Preliminary Checks

• I have searched existing issues to ensure this feature hasn't been requested before

Problem description

The Analysis Function charts guidance states it is acceptable to break a numerical y-axis on a line chart when necessary. However, Matplotlib and Plotly do not have a built-in method to add break symbols to an axis (two slashed lines: //).

Possible solutions

Solutions to this issue could include:

• Example code: Add example code to the cookbook demonstrating how to manually add an axis break symbol in Matplotlib and/or Plotly (if possible)
• New functionality: Add functionality to the package that automates or semi-automates the addition of an axis break symbol.

A solution would be needed for both Matplotlib and Plotly if possible. If you are tackling just one of these, please create a specific sub-issue for Matplotlib/Plotly accordingly.

Examples

• This Matplotlib example shows how to add a break symbol to an axis in Matplotlib, though it's manual and clunky.
• Analysis Function line charts guidance: Figure 14