Radar chart rendering issue

[stockiNail]

Expected Behavior

The rendering of a radar chart works correctly with version 2.8.0.

Current Behavior

Using the development build, the rendering of the chart will apply a "white" area in the middle of the chart itself.

Steps to Reproduce (for bugs)

https://codepen.io/anon/pen/ymyXeW

Environment

• Chart.js version: DevBuild: https://www.chartjs.org/dist/master/Chart.min.js
• Browser name and version: FF 68.0

[stockiNail]

More info: the bug occurs ONLY when you have got negative data.

[nagix]

#6281 added support for boundary filling modes in radar charts to make it consistent with line charts. While fill: true is equivalent to fill: 'origin' in line charts, fill: true might be better to be equivalent to fill: 'start' in radar charts for better backward compatibility.

@etimberg @benmccann Any comments?

[benmccann]

I haven't done much with radar charts, so I'm sure what start, end and origin fill means. It looks like we don't have any documentation explaining that, so it could be good to add. I don't have any objections one way or the other since I don't really know about this option

[stockiNail]

@nagix @benmccann I have tested the "master" with the updates of PR 6281 being committed into the master.

Could you confirm me that to have the same behavior I must use "fill: start" instead of "fill: true"?

[benmccann]

@stockiNail you probably know more about the radar chart than I do and @nagix has been away for a little while. If there's some docs that are wrong or missing here, we'd be open to a PR to fix :-)

[stockiNail]

@benmccann OKI! Anyway using fill: start works... Maybe it could be set as Default at radar dataset options (new ones). I'm not so expert about javascript but I'm gonna have a look and open a PR if needed. A day has got only 24 hours... unfortunately ;)