Describe labeling placement rules

[DelazJ]

Fixes #9244

Goal:

Ticket(s): #

• Backport to LTR documentation is requested

[DelazJ]

@nyalldawson I couldn't find what the rule priority is supposed to do here. Any help? Thanks.

[nyalldawson]

@DelazJ it's the same as https://docs.qgis.org/3.34/en/docs/user_manual/style_library/label_settings.html#priority -- in the situation where labeling conflicts arise, it's used to determine which label "wins" and gets its ideal placement.

So here a low priority would mean "try to do this, but compromise if other more important rules need to be respected", and a high priority would be "this rule is more important, compromise elsewhere if needed"

[DelazJ]

OK, Thanks. I thought it was something between the rules themselves.
Then why is this rule the only one with that setting? Someone may want "Prevent labels overlapping features" more than anything else. And afaics this isn't possible unless they use the "priority" setting in the target layer "Placement" tab. And if that works, can't we do the same for the layer we want to keep their labels away from others, i.e. simply adjust the priority in the layer placement tab? Why a specific slider?

[nyalldawson]

Then why is this rule the only one with that setting?

It was only in scope of works for that rule, and would have required a lot of development for it to work with the others.