Feature request #20353

Deterministic label placement

Added by Alexey T over 1 year ago.

Status:Open
Priority:Normal
Assignee:-
Category:Labelling
Pull Request or Patch supplied:No Resolution:
Easy fix?:No Copied to github as #:28174

Description

Make deterministic label placement.

When scrolling map, labels are jumping from place to place. This introduces an problem for tiled export. When map is cut to tiles, every tile is rendered independent of another, and labels appear to be cut in pieces which do not stich.
This behaviour is also visible in the way QGis Server renders tiles.

Label placement engine should calculate label position once and independent of canvas size and location. As far as I know this is how Mapnik does.
Also calculated label position could be reused to speed up drawing.

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