Text rendering issue in symbol layer when map is rotated/tilted

[westnordost]

Describe the bug

When the map is tilted or rotated, text labels in a symbol layer are sometimes not rendered at all or rendered in a warped way. (As seen in the video) the warping seems to persist when rotating back to tilt=0, rotation=0

https://github.com/user-attachments/assets/7c24179a-d3a1-4796-ab85-1cf8423dbea1

(This video was made with Android 9, Moto X4.)

https://github.com/user-attachments/assets/43990869-703a-44c4-837c-df16c7039cf8

To Reproduce Reproducible with https://github.com/streetcomplete/StreetComplete/releases/tag/v59.0-alpha2

Style affected:

SymbolLayer("pin-cluster-layer", SOURCE)
  .withFilter(all(
    gte(zoom(), 13f),
    lte(zoom(), CLUSTER_MAX_ZOOM),
    gt(toNumber(get("point_count")), 1)
  ))
  .withProperties(
    iconImage("cluster-circle"),
    iconSize(sum(literal(0.5f), division(log2(get("point_count")), literal(10f)))),
    textField(get("point_count")),
    textFont(arrayOf("Roboto Regular")),
    textOffset(arrayOf(0f, 0.1f)),
    textSize(sum(literal(15f), division(log2(get("point_count")), literal(1.5f)))),
    iconAllowOverlap(true),
    textAllowOverlap(true),
)

Expected behavior Text renders correctly

Platform information:

• Android, any version
• Version 11.2.0

Additional context

Originally reported in https://github.com/streetcomplete/StreetComplete/issues/5859

So far, the same issue could NOT be reproduced for the following layer, even though it is also a symbol layer with text:

SymbolLayer("overlay-symbols", SOURCE)
  .withFilter(all(
    gte(zoom(), 17f),
    isPoint()
  ))
  .withProperties(
    iconImage(get("icon")),
    iconSize(interpolate(linear(), zoom(), stop(17, 0.5f), stop(19, 1f))),
    textField(get("label")),
    textFont(arrayOf("Roboto Regular")),
    textAnchor(Property.TEXT_ANCHOR_TOP),
    textOffset(switchCase(has("icon"), literal(arrayOf(0f, 1f)), literal(arrayOf(0f, 0f)))),
    textSize(16 * context.resources.configuration.fontScale),
    textColor(if (isNightMode) "#ccf" else "#124"),
    textHaloColor(if (isNightMode) "#2e2e48" else "#fff"),
    textHaloWidth(2.5f),
    iconColor(if (isNightMode) "#ccf" else "#124"),
    iconHaloColor(if (isNightMode) "#2e2e48" else "#fff"),
    iconHaloWidth(2.5f),
    textOptional(true),
    iconAllowOverlap(true),
    textAllowOverlap(step(zoom(), literal(false), stop(21, true))),
    symbolZOrder(Property.SYMBOL_Z_ORDER_SOURCE),
  )

This suggests that certain properties may trigger the issue and it can not be reproduced with just any text on any symbol layer.

[mtpdog]

I have the same issue. It started from the version 11.1.0. The latest stable version without this issue is 11.0.2-pre0. According to my short tests 11.2.0 also have some additional weird tile loading issue (some tiles are blinking even when they are already loaded). Probably this is a related rendering bug.

[louwers]

cc @sjg-wdw

[louwers]

I tried to reproduce this in our test app. No luck so far...

https://github.com/maplibre/maplibre-native/commit/3cf9a8ea9aceb79b8b6edca09f1d0556378e4297

@westnordost Can you try removing the expressions which use logarithms?

[mtpdog]

Can you try removing the expressions which use logarithms?

According to my test this doesn't seem to be related to exponential interpolation. I have the same issue with linear interpolation and without interpolation at all.

[westnordost]

I removed everything from the layer style except this

        SymbolLayer("pin-cluster-layer", SOURCE)
            .withFilter(all(
                gte(zoom(), 13f),
                lte(zoom(), CLUSTER_MAX_ZOOM),
                gt(toNumber(get("point_count")), 1)
            ))
            .withProperties(
                textField(get("point_count")),
                iconAllowOverlap(true),
                textAllowOverlap(true),
            ),

and it is still reproducible with this.

Note that I wasn't able to reproduce this issue with things such as shop names or housenumbers yet

[louwers]

@westnordost Could you try reproducing it with https://github.com/maplibre/maplibre-native/commit/3cf9a8ea9aceb79b8b6edca09f1d0556378e4297 ?

[westnordost]

Hm, I didn't check out and setup this project on my computer yet. You want to see if it is maybe device-specific? After all, you already found that you cannot reproduce it with https://github.com/maplibre/maplibre-native/commit/3cf9a8ea9aceb79b8b6edca09f1d0556378e4297 . To see if it is device-specific, I think it would be quicker if you installed https://github.com/streetcomplete/StreetComplete/releases/tag/v59.0-alpha4 on your test device, zoomed out after the quests were downloaded until the clusters are visible and then rotate, push around and tilt the map to see if you have the same effect on your test device. (No checking-out+setup of my project necessary :-P)

[westnordost]

@mtpdog are you using clustering?

[louwers]

Sure I can do that!

Looks device specific. No problem on Samsung S10 with LineageOS (Android 12).

[westnordost]

Hm, weird. Note, though that it does occur not always on rotation, you have to push it around, zoom in and out, maybe tilt a bit. I didn't find if there is any specific thing that triggered it (other than definitely: rotation, but I don't know the second magic ingredient). I for example wasn't able to reproduce it on my Samsung S10e with LineageOS (Android 13) in some village that had few quests (=small and few cluster bubbles), only in some city with many quests. But this might as well have been coincidence.

Also, I was never able to reproduce on my phone what you can see in the first video posted in the issue. For me, the numbers only sometimes vanish, but never warp.

[westnordost]

Devices on which it was confirmed that it can be reproduced so far (I will update this post as new information from users comes in):

Warping text:

• Android 9, Moto X4

Missing text:

• Android 13, Samsung Galaxy S10e
• Android 14, unknown Motorola phone

[mnalis]

I also occasionally had warping on Android 14 (Samsung Galaxy S23+) like this:

https://github.com/user-attachments/assets/039d07ea-0bf5-4cef-871d-f14856e5fde3

[mtpdog]

are you using clustering?

No, I don't. But I use custom fonts from my "glyphs" folder.

[mtpdog]

My suggestion is to examine changes made between versions 11.0.2-pre0 (the last working one) and 11.1.0 (this already includes warping).

[sjg-wdw]

A lot going on in this thread, but I think at the core is a problem with clustering. Do we have any good clustering tests?