An option to change Folder colors

I had a long discussion on IRC about that with @ernestask & @csoriano on use cases, that proved it needs lots of write up to provide good points on why this feature is really useful, and it is vastly depended on user workflow. However it is a well establish pattern used in many applications that make use of folders (eg Google Drive, elementary Files, Folder Layers on GIMP or After Effects etc)

Use cases

Coloring specific folders helps us to faster identify them, because eye-scanning for color is faster than eye-scanning text. It makes sense on folders we most often use. For example on my $HOME/Downloads I mostly often want to go into "Torrents" directory. Since $Downloads is usually a mess, I mostly use "Search" rather try to discover "Torrents". If I could set a different color, I would speed up the process.

It is somehow (but not exactly) similar to XDG_Folders that have special icons on them, so they can be recognized easier (XDG_Music, XDG_Photos etc)

Bookmarks

It is different from "Bookmarks" because bookmarks can only work for a few items

Starred

It is different from "Starred" because it keeps hierarchy and navigation

Recent

It is different from "Recent" for the exact same reason as for "Starred", plus we never know what's inside Recent, until we open them

Custom Icon

It is different than setting custom icon from Folder Properties, because we can't pick a folder with a different color, since Adwaita Icons doesn't support that. Also custom icon doesn't work well for a variety of other reasons

What is not

It is not a real color-tagging system. It only leverages an already available functionality of GNOME Files, to be able to set different folders (or icons in general)

Benefits of the solution

It is a functionality that people already use, so there is strong familiarity, plus it is a feature that won't annoy, decrease usability or distract the users that don't want to use it

Possible drawbacks

None I can think of from a user POV. @ernestask mentioned there should be some attention on selection colorizing

How it could work

I believe a number of 8-9 colors would be optimal. Adwaita Icon Theme (cc @jimmac @aday @bertob @snwh) could documented 9 color variants, that would be "hardcoded" so all rest icon set could use those

For example:

{
  Default color: could be anything
  Blue,
  Red,
  Green,
  Light Green,
  etc,
  There is already an color pattern for GNOME HIG I can't find now :/
}

Adwaita Icon theme should make use of the exact colors as those are displayed on selections, but third party icon themes, could use slight variations of the colors

It should also work on a multi-selection. For example we should be able to select 2 or more folders to set them a different color, or remove the different color and go back to default

Mockups

Those aren't meant to be accurate, just illustrating the idea

On context Menu

With Popover -the future :p

From Properties

Color Filtering

That is an idea from Deepin Filemanager! It is not part of this proposal, just a fun-idea, but in actual use I must say it is pretty neat!

"Reality be rent.. Synapse break... Vanishment this world :p"