New customization option is now available in Performance Objectives app for the following dashboard gadgets: Performance Objectives, Performance Trend, Multi Metric Combined Chart, Multi Metric Trend Chart, Heat Map, Change History, Scatter & Bubble.
Choose how to align your Label name (the name for the ‘Display By’ Jira field).
You will find the new customization option in the More Settings section as shown here:

Check the following video example of how label rotation feature would change your chart view and choose auto or custom rotation based on your needs (time to watch 00:38 min):
The option may be useful when your ‘Display By’ field has long name yet you need to fully visualize it in your report (e.g. for a printable or pdf version), like Assignee, Issue Summary, etc.
Please note that the report is interactive on your dashboard and the names are fully visualized by scrolling on the chart.
Check all styling and customization options under Customization category.
Start your 30 days free trial of Performance Objectives: Charts for Jira from Atlassian Marketplace.