Allow style editing of graph legend labels

[notwopr]

Thanks so much for your interest in Dash!

The feature has already been tangentially discussed here: https://community.plotly.com/t/scatter-plot-how-to-wrap-legends-text-when-legend-text-is-too-long/4767/7

Is your feature request related to a problem? Please describe.
I have traces that have very long names. It's problematic because the legend text does not word wrap and so it squishes the graph.
Here's an example: https://postimg.cc/VSq0bQXW

Describe the solution you'd like
Please allow for more stylistic control over legend text, particularly allowing for textoverflow control, like word wrap, hidden+ellipsis, hover tooltip etc.

Describe alternatives you've considered
I had to resorted to displaying a hashmap to translate the long text into a shorter signature.

Additional context
I've had it where the text is really long that the actual graph is completely unreadable.

[ned2]

Enhancements around the legend formatting would likely be added to plotly.js rather than Dash.

It looks like there's already a few couple of related issues on this topic over there.

• Word wrap for long labels #382
• Automatic hover text wrapping #1964

One thing you could do as a workaround is truncate the name of the trace in the underlying figure. This is where trace names are sourced from for building the legend. It's possible the field is used elsewhere, which means it would be truncated to there. Luckily the default hover text does not seem to be affected.

import plotly.express

df = px.data.gapminder()
df = df[df["continent"]=="Europe"]
fig = px.line(df, x="year", y="lifeExp", color='country')

max_len = 15
for trace in fig.data:
    if len(trace.name) > max_len:
        trace.name = f"{trace.name[:max_len]}..."

[notwopr]

Thank you that makes sense it is for plotly and not dash. Thank you for the references. I'll look into it.