Area style stroke-width is ignored

[andreynovikov]

I've tried to set wide outline for area (3.0 in my case) and didn't get desired result.

[devemux86]

Probably something in PolygonBucket GL calls?

[devemux86]

See commit 3c9e18d in issue_121 branch how it fixes the problem.

Currently we use the HairLineBucket width 2 everywhere, set in above line.
Thorough testing is needed to check map's rendering after the change.

@hjanetzek any hint on this?

[hjanetzek]

The Area outline was mainly intended to get cheap anti-aliasing.The maximal GL_LINES width is hardware dependent and thicker lines would also have ugly cut-offs on steep angles. For hi-dpi displays 4px may look ok though, if the hardware supports it.

For thicker lines one should use an additional LineLayer

[devemux86]

The maximal GL_LINES width is hardware dependent and thicker lines would also have ugly cut-offs on steep angles.

@hjanetzek thanks for the info, indeed with the change too large values have visual artifacts.

OpenGL is different in many ways than software rendering, we must keep that in mind.

[andreynovikov]

For thicker lines one should use an additional LineLayer

This is how I do it now, but the problem with line is that it does not support smooth fading, so my area fades but line stays solid.

[devemux86]

I find line fade working.
It needs good care the fade value not being smaller than the zoom where the element actually exist in the map.

[andreynovikov]

Do you mean just disappearing or smooth transparency change?

[devemux86]

The fade works similar in lines and areas, also behaves like the zoom-min.

If setting zoom-min="14" or fade="14" in the theme, but the data were declared with zoom-appear="15" in tag-mapping, then they'll appear on zoom 15 and the fade will not work too.

[devemux86]

I think we can close this.

[devemux86]

Better use separate lines for area outlines to avoid rendering problems:

Before:

After: