How to disable symbol fading when location moves?

[gregorypeckdom]

I've created a Map Libre app very similar to the Add live realtime data example. I have a symbol layer and the symbol's position is periodically moved via the setData() method.

Is there a way to disable the "fade" animation when the symbol moves? When the symbol is drawn at its new location, there is maybe half a second where it goes through an animation where the alpha value of the symbol increases from 0 to the max value.

Thanks in advance!

[HarelM]

I has a similar problem.
I think you could use icon-allow-overlap to solve this (maybe).
If this doesn't work you can use fadeDuration: 0 when initializing the map, but then you don't have fade in for other symbols, which is not great...

[gregorypeckdom]

Thanks, that really helped. By setting 'icon-allow-overlap: true I don't see the fading anymore. This setting is fine because I wanted my symbols to always be visible even if they collide.

While implementing this change, I noticed a discrepancy between MapLibreGLJS and the style spec. The style spec says icon-allow-overlap... Disabled by icon-overlap.. However, it seems like icon-allow-overlap controls fading even when icon-overlap is provided. Meaning icon-allow-overlap isn't fully disabled when icon-overlap is also provided.

One last question, is there a subpixel positioning setting for symbol layers like there is for the marker layer? I noticed the same effect where the symbol icon "shifts" when my zoom operation is complete. I was able to fix this for markers with subpixel positioning, but I don't see the same option for symbols.

[HarelM]

Can you elaborate? Symbol position is defined in the tiles usually, and you have 4K of data on a 256 pixels tile, so you have subpixel precision. Or am I missing something obvious?

[gregorypeckdom]

Sure, I was able to reproduce the issue in the Draw Geojson Points example. Looking at the 2013 symbol, when I zoom in with the mouse wheel, sometimes at an end of the zoom the symbol shifts over one pixel.

I captured a video from my machine, it's not the highest quality but hopefully you can see the effect. Hopefully you can also reproduce it on your machine.

Screen.Recording.2025-11-12.151150.mp4

I'm on Chrome Version 142.0.7444.61 (Official Build) (64-bit) with Windows 11. Let me know if you have any follow up questions.

[HarelM]

Yeah, I see, seems like a bug in how a symbol is rendered as I don't think it should be moving, I don't think it's related to switching between integer zoom values as it see if every time I changed the zoom a bit.
So probably a very hard bug to solve...

[gregorypeckdom]

Thanks for all your help. Just to be thorough, I logged a bug #6699 to track this issue. Thanks!
(edit - fix bug #)