Support setting username and avatar colors in custom themes

[bwindels]

Partially overlaps with #4373, but introduces fewer new symbols in the custom theming JSON blob. Also supports avatar backgrounds.

Documentation updates at element-hq/element-web#13406

[turt2live]

@bwindels have we considered the security implications of this?

[bwindels]

@bwindels have we considered the security implications of this?

Oooh, not at all 🤦 I guess if I ensure it is a hex color it would be fine?

[turt2live]

It's more that allowing people to change them can lead to themes which remove/alter the disambiguation technique.

[bwindels]

It's more that allowing people to change them can lead to themes which remove/alter the disambiguation technique.

Hmm, I see. People are in control though of the theme they choose?

[turt2live]

I guess so. This is the consideration part of the conversation :p

It's probably fine, assuming product is okay with it.

[bwindels]

It's probably fine, assuming product is okay with it.

They are asking for it :)

[turt2live]

that needs to be captured somewhere public :(

[turt2live]

lgtm assuming tests pass

[fooness]

Just tried using "username-colors": ["#rrggbb", "#rrggbb", "#rrggbb", "#rrggbb", "#rrggbb", "#rrggbb", "#rrggbb", "#rrggbb"] as well as "avatar-background-colors": ["#rrggbb", "#rrggbb", "#rrggbb"] in my config.json on a fresh build of 1.6.0-rc4, but unfortunately that didn’t work.

Using "username-colors_1": "#rrggbb" (and 2, 3, …) worked! Could not verify the same for single definitions of avatar-background-colors, though. Not sure if I did anything wrong, I bet it was tested before being merged … but I also don’t know what I might have done wrong in my config.json …

[t3chguy]

This isn't in 1.6.0-rc4. It is only in develop.