[QGIS-Developer] Advice? Sneaky trick for call out labels

[Tim Sutton]

Hi Friends

So I am using logic like this* to make call out labels using a geometry generator:

make_line(
  closest_point($geometry,
  make_point( "auxiliary_storage_labeling_positionx" , "auxiliary_storage_labeling_positiony" )),
  make_point( "auxiliary_storage_labeling_positionx" , "auxiliary_storage_labeling_positiony" )
)

The line runs from the closest point along the edge of the polygon to the bottom left corner of the label box. With this configuration it works well when my ‘lollipop’ callout label is north-east of the polygon being labelled:



But doesn’t work when the label is e.g. south west of the polygon:



Now I am wondering if we have any options for getting the geometry of the label box so I can do the reverse and get the closest point along the edge of the label box to the polygon being labelled. So my question:

Is there any sneaky trick for getting the geometry of the label box for a feature in an expression? And no, using an opaque background for my label to mask away the call out line doesn’t really hack it. I know the label box isn’t being calculated at the time the polygon is being rendered so the answer is probably ’no’ but maybe someone else has a clever idea to make may lollipops work when labels are south (or east or west for that matter) of the feature being labelled?

Thanks!

Regards

Tim



—









Tim Sutton

Co-founder: Kartoza
Ex Project chair: QGIS.org

Visit http://kartoza.com <http://kartoza.com/> to find out about open source:

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Skype: timlinux 
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