Make colors different when graphing 2 different lines

[macobo]

Is your feature request related to a problem?

When creating a graph with two actions/events or breakdown generates 2 distinct groups, the colors used always seem to be blue.

Example:

Describe the solution you'd like

Use distinguishable colors.

Describe alternatives you've considered

Hovering over things

Additional context

Came up during #2560

Thank you for your feature request – we love each and every one!

[paolodamico]

+1 from customer call this week

[paolodamico]

@lottiecoxon might be worth giving some deep thought as to which colors we should use here. From a customer call several weeks ago we also got the feedback that the colors we're using don't have a good enough contrast ratio and are particularly hard to read for color-blind people, and particularly relevant now that you're working on a new palette.

[paolodamico]

Related to #1763.

We need to address this soon, check out this example.

[lottiecoxon]

Hey @paolodamico sorry for the really long delay, I just realised there were a lot of mentions on GitHub that I have missed, so I will get to these all today!

I found this article online so will work on a colour blind friendly scheme - https://venngage.com/blog/color-blind-friendly-palette/

[lottiecoxon]

Here are 4 colour schemes, laid out so you can see the 'normal' colour vision on the top level, and below how these colours are seen by people with the two most common colour blindness types.

[mariusandra]

Hey, this used to be fine, but something messed it up.

For some context, we can't just hardcode colors as we'd go crazy with all the different options. We have five different backgrounds (black, white, blue, green, purple) and we need colors on all of them that look good with the background, yet different from each other. Plus we need about 20 unique colors for each of them.

I had created a system to generate any number of relatively unique colors for every background we can throw at it, but this doesn't seem to work anymore. Now every line is just blue. Thus it's a bug that needs to be fixed. I might have a look a bit later today.

[mariusandra]

All backgrounds were presumed to be white due to a bug. Now the lines on the colored backgrounds look better, though this probably doesn't fix the initial issue.
#2911

[mariusandra]

I found a fix for the two blue lines problem as well: 4c781df

Turned out to be a 🤦

[paolodamico]

I think the immediate impact has been addressed. However I do think we still need to do a better job setting high-contrast colors, which are also as different from each other as possible. See below a graph with a simple breakdown, the gray ones are very hard to see (and it's definitely not-accessible). I do think this is a matter more on the design side than engineering.

[Twixes]

New graphs have this.