Default color cycle is too short

[jlstevens]

As part of #1518 I noted that our current color cycle is very short:

For comparison, the matplotlib 2.0 color cycle has 10 colors:

One suggestion is to extend our color cycle by appending the matplotlib purple, brown and any other distinguishable colors.

Another suggestion is to use the large color cycle in datashader that is the union of Set1,Set2 and Set3 (minus colors that are too similar).

Personally, I don't find all these colors quite distinguishable enough so I prefer the first option (extending our current cycle, especially as it is likely to cause less disruption).

[ea42gh]

http://colorbrewer2.org/#type=qualitative&scheme=Paired&n=12

you might also consider a sequential scheme. Note that colorblind schemes might be a useful alternative

[jlstevens]

@ea42gh We are considering just extending the existing color cycle. Do you have any particular issues with it (other than length) that would lead you to recommend something else entirely different?

[jlstevens]

@jbednar @philippjfr I don't think we ended up doing this for 1.8. Should we try to do it for 1.8.1? And if so, should we pretend we did do it so it can fall under the style_17 compatibility switch?

[jbednar]

I think it would fall under style_17 in any case, so it's not pretending, because that switch needs to restore whatever 1.7 did. Do you mean, so that we don't also have to make a style_18 switch? Sure.

[jlstevens]

Do you mean, so that we don't also have to make a style_18 switch? Sure.

Right.