White background for edge labels in plot of graph

[enadeau]

When you plot a graph with labels on edges, the label usually appear directly on the edges and it's not very good for readability.

The objective is to add an option to Graph.plot() to specify the background color of the label.

Example (see attach)

    sage: Word('001101').suffix_tree().plot()

CC: @thecaligarmo @jm58660

Component: graph theory

Keywords: graph plot, edge label

Author: Émile Nadeau

Branch/Commit: 94f5db1

Reviewer: Jori Mäntysalo

Issue created by migration from https://trac.sagemath.org/ticket/23071

[enadeau]

Attachment: before.png

[enadeau]

Branch: u/enadeau/white_background_for_edge_labels_in_plot_of_graph

[enadeau]

Attachment: after.png

[enadeau]

New commits:

7297d35	Trac #23071: Add the option edge_labels_background. Default is now "white"
55eb667	Trac #23071: Document the new option edge_labels_background

[enadeau]

Commit: 55eb667

[jm58660]

comment:6

Seems good, but no time for review just now. I'll CC myself because of posets 'plot()` function.

[jm58660]

comment:7

Did you test edge_labels_background=None with or without dot2tex? It seems that without that it works incorreclty. I tested with

graphs.PetersenGraph().show(edge_labels=True, edge_labels_background=None)

[enadeau]

comment:8

Replying to @jm58660:

Did you test edge_labels_background=None with or without dot2tex? It seems that without that it works incorreclty. I tested with

graphs.PetersenGraph().show(edge_labels=True, edge_labels_background=None)

You have to use

graphs.PetersenGraph().show(edge_labels=True, edge_labels_background="None")

because the parameter must be the string "None". I know this is not very intuitive, I'm looking for a way to make it clearer it the documentation if you have any idea.

[jm58660]

comment:9

Ah, OK. I think that edge_labels_background="opaque" would work better.

[jm58660]

comment:10

Replying to @jm58660:

Ah, OK. I think that edge_labels_background="opaque" would work better.

Nope, src/sage/plot/graphics.py uses "transparent" so better to use the same terminology.

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

94f5db1

Trac #23071: Change the option from "None" to "transparent" to achieve a

[sagetrac-git]

Changed commit from 55eb667 to 94f5db1

[jm58660]

comment:12

Now it seems good. Thanks for this.

[jm58660]

Reviewer: Jori Mäntysalo

[vbraun]

Changed branch from u/enadeau/white_background_for_edge_labels_in_plot_of_graph to 94f5db1