Flickering water labels about streetcomplete-mapstyle

[Helium314]

Looks like if value can't be parsed there is some fallback instead of a crash, and this fallback works better than the currently used value.

Anyway, (20 + feature.scalerank).toString() works, and strings are interpreted correctly (tested with place-labels)

[Helium314]

The problem is

streetcomplete-mapstyle/layers/labels.yaml

Line 28 in b13d785

priority: function() { return 20 + feature.scalerank }

removing the 20 + makes the flicker go away.
Using other values instead of 20 changes label placement a little, but so far I always found at least some flickering for the values I tested.
Even when using 0 instead of 20.

[matkoniecz]

I am pretty sure that I have seen this problem in 45.1 and earlier, also for water labels

[Helium314]

Maybe, but I just tried older version to see when it started, and I haven't seen it in a short test using 45.1 older versions. So even if it was there, it's much more frequent in newer versions.

[westnordost]

In the end, isn't this rather an issue of tangram rather than the mapstyle?

[Helium314]

Maybe it is, but at the same time it was probably triggered by a change in map style (didn't look up what exactly could have caused it) and I didn't notice any issues / bad placement of water labels previously.

[mnalis]

• possibly related: streetcomplete/StreetComplete#4350

[westnordost]

Is "priority" maybe supposed to be a string in the end?

[Helium314]

At least for place-labels an integer works fine for the correct order...

[westnordost]

So weird... what is the pattern there...? Maybe the missing semicolon at the end is the issue?

[Helium314]

I think I already tried that, without effect

[Helium314]

Is "priority" maybe supposed to be a string in the end?

... but maybe still it somwhow is?
priority: function() { return ${20 + feature.scalerank} } works (though I'm not even sure whether this actually results in a string as I didn't check how yaml parsing works...)
I didn't find any difference in label placement compared to priority: function() { return feature.scalerank } though

[westnordost]

Uh, what does function() { return ${20 + feature.scalerank} } in Javascript even do? (If this is a string placeholder like in kotlin, shouldn't there be quotes around that?)

[Helium314]

So this is javascript? I have no idea how yaml files are parsed and just did more or less "random" things.

[westnordost]

(In Firefox console)

[Helium314]

I wonder why there is no error message in SC / Tangram... and why this actually works better than the current version (for flickering and not hiding pins)

[matkoniecz]

why this actually works better than the current version (for flickering and not hiding pins)

Maybe it is broken and therefore is not triggering broken functionality in Tangram? With two bugs negating each other?

[westnordost]

Anyway, (20 + feature.scalerank).toString() works, and strings are interpreted correctly (tested with place-labels)

So, this is the fix to make it all work?

[Helium314]

With this change I am unable to reproduce both the flickering labels and the pin disappearing on the house linked in streetcomplete/StreetComplete#4522 (comment)

[westnordost]

Do you plan to create a PR for this?

[Helium314]

I still don't have much time (and currently not even working Android Studio), but that's only a simple change to be done online...
Will do it tomorrow, of you can just commit it if you want it quicker.

[Helium314]

This should be fixed with #142