lineWidth has no effect when boost is enabled for line series

[manu-st]

If you set lineWidth to a value different than 1, then this setting has no effect when boost is enabled. I saw a few references in the highcharts forum about this but no github issues. Is the solution to use triangle to fix this planned?

See https://www.highcharts.com/forum/viewtopic.php?t=39846
See https://mattdesl.svbtle.com/drawing-lines-is-hard

Expected behaviour

The line should have the specified width.

Actual behaviour

All lines have a width of 1.

Live demo with steps to reproduce

boost enabled: http://jsfiddle.net/c619o4ek/
boost disabled: http://jsfiddle.net/1nmt6awz/

Product version

6.x and 7.x

Affected browser(s)

Chrome

[sebastianbochan]

Hi @manu-st,
Thank you for reporting about the bug.

Internal note
The style mode also ignores lineWidth

Demo:

• http://jsfiddle.net/BlackLabel/nh6g90r7/

It looks like these lines overwrite options.

                if (settings.lineWidth > 1 && !H.isMS) {
                    gl.lineWidth(settings.lineWidth);
                }

@cvasseng

[TorsteinHonsi]

The style mode also ignores lineWidth

That's expected behaviour, instead stroke-width must be set in CSS.

[manu-st]

@TorsteinHonsi What do you mean exactly? If a special css style is needed, why doesn't Highcharts do it automatically for us?

[TorsteinHonsi]

Sorry for the confusion @manu-st. My comment is actually off topic, it answers to @sebastianbochan's comment about styled mode.

But it is not relevant to the issue, which is boost mode. We will be cack with a comment on that.

[cvasseng]

Hey @manu-st, we're currently looking into using either triangulation or some shader magic to properly implement lineWidth. The issue is, as you alluded, that WebGL lacks support for setting line width in a consistent manner (modern WebGL implementations only supports a line width of 1.0). I will get back to you shortly with more details in terms of time frame/feasibility.

[iamanoopmk]

In the latest version of Highcharts this issue is still there. Any updates on this?

[pawelfus]

@cvasseng FYI

[90michael]

Any news?

[pawelfus]

We will investigate the issue and let you know

[pawelfus]

For now, it is considered a boost limitation caused by non-trivial task to implement line-width in WebGL.

Please vote for this feature by adding a thumbs-up reaction to the first post.

We prioritize the most popular enhancements/feature requests.

[TorsteinHonsi]

Since we're implementing support for window.devicePixelRatio (as in Retina), this issue is more important. With a device pixel ratio of 2 (typical Retina), the 1px line width is scaled down to 0.5px.