[ENH]: "Road sign" boxstyle/annotation

[oscargus]

Problem

Not sure what the proper name is, but it may be useful to have boxstyles as below (red part, black is the object if encloses):

Proposed solution

Add boxstyles/annotiation styles as above.

As there already are arrow styles, these should be called something else.

Also, one may consider what pad should mean here. Probably the left alternative where the "arrow side" is not padded (as opposed to the right alternative). Should one be possible to provide the angle or should it always be 45 degrees?

Is there a use for a double-arrowed version?

[anntzer]

I would just make them variants over larrow/rarrow/darrow (https://matplotlib.org/devdocs/tutorials/text/annotations.html#annotating-with-boxed-text), by adding some parameters to the constructors, e.g. head_length, head_width, if possible keeping them consistent with the similarly named parameters in the corresponding arrowstyles?

[oscargus]

That may indeed be a good idea which removes the naming issue if nothing else. A bit more tedious to use, but would for sure enable it (an example where this is obtained can be a nice addition as well, as IMO it looks better).

[oscargus]

Marking as good first issue, but medium as there is a bit of argument handling to be done, including updating documentation and add an example. Bordering easy though. (Go with the suggestion in the comment.)

[timhoffm]

Isn't this more like making https://matplotlib.org/devdocs/tutorials/text/annotations.html#defining-custom-box-styles a first-class style?

[anntzer]

That's also a way to do it, but I'd rather go with the "generalize larrow/rarrow" route.

[Abitamim]

Hi, I am a first time contributer to open-source. I went slightly on my own direction when creating this feature. Please let me know if it is all right, or if I should pursue an option with more flexibility in setting arrow head dimensions.