[BUG] curated color palette for pie chart

[Mattwmaster58]

Sometimes colors are selected that makes it super hard to see between pie pieces:

eg:

[sheepzh]

the color palette now is default from echarts

please tell me if you have any idea

[Mattwmaster58]

I'm not sure whether this should be an upstream issue, but I noticed that the theme colors "wrap" around playing around here: https://echarts.apache.org/en/theme-builder.html

So this is only a problem for when (number of slices) == (number of theme colors + 1). If it's more, it's fine because of how it wraps the color usage (you can see in the theme explorer).

I think the fix in the upstream would be to have a special case for pie charts where the amount of data is theme colors + 1, use anything but themeColors[uniqueDataElements % themeColors.length], if that makes sense.

[sheepzh]

it's a good idea, but now i dont find any API to count the color palette which is different among Echart's versions. so i ll try to use another method to detect this issue.