[Patch] getVisibleLayersInZOrder() -> Comparator is not transitive

[michael2402]

if (l1 instanceof OsmDataLayer && l2 instanceof OsmDataLayer) {
     if (l1 == getActiveLayer()) return -1;
     if (l2 == getActiveLayer()) return 1;
     return Integer.compare(layers.indexOf(l1), layers.indexOf(l2));
} else
     return Integer.compare(layers.indexOf(l1), layers.indexOf(l2));

The current comparator implementation is not transitive. Imagine the following layers:

layers = [OSM1, TMS1, OSM2], activeLayer = OSM1

We have OSM1 < TMS1, TMS1 < OSM2, OSM2 < OSM1.

What was the Idea behind the Comparator? My idea would be that it should push the avtive data layer above all adjacent OSM layers. So it would change this:

[OSM1, OSM2, OSM3, TMS1, OSM4], activeLayer = OSM2 to [OSM1, OSM3, OSM2, TMS1, OSM4]

[Don-vip]

Replying to michael2402:

What was the Idea behind the Comparator?

That's very old stuff, it was done in r1943 to address #3228. Probably to paint GPX layers behind OSM data layers.

[michael2402]

Obsolete with patch #11631, I added a new layer ordering code there.

[bastiK]

The code is unchanged, so not fixed.

[michael2402]

This patch should fix the issue. The idea of the comparator - to move the selected data layer to the front but not above e.g. gpx layers - is respected.

[bastiK]

In 8613/josm:

fixed #11496 - getVisibleLayersInZOrder() -> Comparator is not transitive (patch by michael2402)

[bastiK]

Thanks!

[wiktorn]

Isn't this problem related to this patch, that my fresh custom build show imagery layer (WMS) above data layer, although in the layer list it's the opposite? When I moved down the data layer, it was showed on the top of WMS imagery layer.

[michael2402]

I missed a Collections.reverse(ret); when preparing the patch... It should not be there.

[wiktorn]

Ticket #11712 has been marked as a duplicate of this ticket.

[bastiK]

In 8615/josm:

fixed a Collections.reverse that should not be there (fixes #11496, patch by michael2402)

[Klumbumbus]

Ticket #11717 has been marked as a duplicate of this ticket.

[Don-vip]

Milestone renamed