[Regression] Label/diagram placement on centroid is broken for multipolygons

[qgib]

Author Name: Anita Graser (@anitagraser)
Original Redmine Issue: 13558
Affected QGIS version: master
Redmine category:labelling

---

Label/diagram placement on centroid in master seems to be off compared to 2.10: for multipolygons, it seems to randomly chose the centroid of one part rather than the old behavior which seemed to use the whole multipart feature to compute the centroid.

In the following example the diagram is put on the centroid with high priority and the label settings are shown.

!210-vs-master.png!

Tested on nightly OSGeo4W

---

• 210-vs-master.png (Anita Graser)
• label-partial-feature.png (Anita Graser)

[qgib]

Author Name: Anita Graser (@anitagraser)

---

• 9163 was configured as 210-vs-master.png

---

• 210-vs-master.png (Anita Graser)

[qgib]

Author Name: Nyall Dawson (@nyalldawson)

---

• priority_id was changed from High to Severe/Regression

[qgib]

Author Name: Anita Graser (@anitagraser)

---

• subject was changed from [Regression] Label/diagram placement on centroid is broken for multipolgons to [Regression] Label/diagram placement on centroid is broken for multipolygons

[qgib]

Author Name: Anita Graser (@anitagraser)

---

Update info: If label all parts of multipart feature is enabled ...

When the complete multipolygon is visible in the map view, there are no label candidates on the main land. They appear if the feature is moved partially outside the map view:

!label-partial-feature.png!

---

• 9164 was configured as label-partial-feature.png

---

• label-partial-feature.png (Anita Graser)

[qgib]

Author Name: Nyall Dawson (@nyalldawson)

---

Seems to be caused by the recent GEOS c++ changes (tolerance) - if I build without the geos c++ library set then the placement matches 2.10. Can also confirm that #2353 fixes this.

[qgib]

Author Name: Nyall Dawson (@nyalldawson)

---

Can you please re-test with current master? PR 2353 has been merged, which fixed the issue for me.

---

• status_id was changed from Open to Feedback

[qgib]

Author Name: Anita Graser (@anitagraser)

---

Looks fine today. Thanks!

---

• resolution was changed from to fixed/implemented
• status_id was changed from Feedback to Closed
• fixed_version_id was changed from Future Release - High Priority to Version 2.12
• done_ratio was changed from 0 to 100