Linear function for label opacity causes rgba stroke values to display incorrectly

[nickidlugash]

The road labels with gray strokes below use a linear function for opacity

"opacity": ["linear", 15, 0, 1, 0, 1]

and a semi-opaque white rgba value for the stroke

"stroke": [1.0,1.0,1.0,0.7],

This is what it looks like at z17:

Is there anything we can do about this?

[mourner]

Can you clarify the expected result?

[nickidlugash]

@mourner I would expect the halos to remain white (i.e. the RGB values remaining the same, the A value interpolating from 0 to 0.7). It looks like instead all the RGBA values are interpolated?

[kkaefer]

This looks like a double-premultiply issue.

[jfirebaugh]

I haven't reproduced this yet, checking to make sure I have the right v3 translation:

      "text-halo-color": "rgba(255,255,255,0.7)",
      "text-opacity": {
        "fn": "linear",
        "z": 15,
        "val": 0,
        "slope": 1,
        "min": 0,
        "max": 1
      }

[jfirebaugh]

@nickidlugash Are you able to reproduce this with a v3 stylesheet?