add text-largest-bbox-only

[talaj]

Adds missing property of text symbolizer.

[yohanboniface]

@springmeyer I see in the wiki that this option is sort of experimental (NOTE: this option may change or be renamed in the future), should we think about some "experimental": true key to add in the symbolizer in such case?

[talaj]

Also the description of this option on the wiki is not very precise. One have to use this option for labeling multi geometries, not just polygons.

[springmeyer]

@springmeyer I see in the wiki that this option is sort of experimental (NOTE: this option may change or be renamed in the future)

Yes, I've hesitated to add this because I'd love to replace it mapnik/mapnik#1583. @talaj - what do you think: is the idea of being able to control labeling like that a good idea? If not then I should probably just stop hesitating and expose this option.

should we think about some "experimental": true key to add in the symbolizer in such case?

I think better to just make a call as per above.

[yohanboniface]

I think better to just make a call as per above.

Seems to me that it's not the first case of feature that exists in Mapnik for a long but doesn't pop up on mapnik-reference because it's not considered stable enough. My opinion is that it would be much helpful for the community to add those features as soon as they exist, but with a key that define their stability status.
Just an example: when using carto, if a symbolizer is not on mapnik-reference you just can't use it, so you can't even test it and give feedback to make it better.
Another suggestion for the key: stability, with the values deprecated, experimental, unstable and stable, the default being stable so we don't need to add the key everywhere.
Thoughts @springmeyer ? :)

[springmeyer]

Another suggestion for the key: stability, with the values deprecated, experimental, unstable and stable, the default being stable so we don't need to add the key everywhere.

Okay, thanks for pushing back: I'm in. We definitely need a way to tag things as deprecated. And so I like combining this into a single stability (or status) category. 👍 to stable being default so we only need the key added in rare circumstances.

[yohanboniface]

Excellent :)
Should I prepare that for 7.0.2? (I guess we need to describe it in datasource.template.json?)
If so, I'll create another issue for tracking this.

[yohanboniface]

Well, it may require an upgrade of at least the minor tag, so we may target 7.1.0 instead, if not 8.0.0, but I'm not sure what is the policy for versioning. :)

[springmeyer]

I think we should go to 8.0.0 because this will add to the reference scheme. It won't be breaking but will still be significant.

[talaj]

@springmeyer I didn't notice mapnik/mapnik#1583 before. It's definitely good idea to use something like multi-policy enumeration instead. Also default behavior should change. I was always thinking something is broken when just one geometry of multigeometry get labeled by default.