Improve the default colors of the charts

[thomasneirynck]

The default color map of the charts can be improved.

Also consider expanding on the seed-colors. There are only 7 of them. A larger default color palette may improve the default visual experience.

[snide]

@thomasneirynck As a follow up. I pulled coloring of visualizations out of my #12085 branch.

I've enlisted @Adrian-J to help come up with some palettes and then I'll help him implement it (with your OK of course). After playing with the system a bit this week I'll say a big thing past the actual colors will be fixing some of the ways we deal with hover states and opacities (for example, area and pie graphs apply a .6 opacity by default, then return it to 1 on hover). If we want to maintain a hover state, we likely need a better system than opacity for this.

In any case, just wanted to give an update.

[thomasneirynck]

@snide @Adrian-J that sounds good. Changing the default colors is fine to do in a separate PR, separate from the Kibana re-skinning efforts.

As for dealing with the highlighting, I'm happy to revise this. Right now, I'm low on inspiration though. Can you explain a little bit more how the current wat of reducing opacity negatively impact changes in the default color palette? What would be a better default way to deal with highlighting? Are you thinking along the lines of:

• Adding an outline
• increasing saturation
• making lines thicker,
  ...

[snide]

Think it's likely just a method. Because dashboard shows all kinds of visualizations next to each other, it looks odd when one of them has the same colors, but is much lighter (because of opacity). The hover callout is fine, but what we shoudl probably do is make the elements not hovered more transparent, rather than making the hovered element more opaque.

In any case, let's let @Adrian-J play around a bit and see what he comes up with.

[snide]

We can probably close this one out now that #13327 exists with a basic spec.

[thomasneirynck]

closing as dupe of #13327.