Support for changing the First day of Week

[lainsce]

Some users might use English or some such locales with a predefined first day in their installs, but that shouldn't lock them from customizing the arrangement of how the week starts (Sunday, Monday, Tuesday etc.) systemwide as well.

Prior Art Gallery:

OS	Picture
macOS
Windows 10

[lainsce]

Mockup of this UI inside the plug:

[ryonakano]

Essentially the same ticket seems to have been posted on elementary/settings-datetime#11. I wonder which Plug is appropriate to expose this setting.

[danirabbit]

I think I'm more inclined to call this a locale issue.

I'm not sure if there's already a place this key is stored. It looks like Evolution carries its own key for this at /org/gnome/evolution/calendar/week-start-day-name. This appears to be part of the app and not part of the data server.

[lainsce]

@danrabbit It'd be a way to override the weekday order that shows in Calendar and the Date Time indicator, for people that have other locale needs but a PC set as English (US), for example. It's more of a "I live in X country where week starts on Monday, but my PC isn't in my locale because I set it so, and as such, my week is starting on Sunday." issue.

My suggestion is to make a global settings key that Calendar and the Date Time indicator both listen to, and make a widget for choosing the weekday you want to start the week on, that edits this key internally.

[mcclurgm]

FWIW I did a bit of digging on week formatting a while back, and setting this globally could be messy. It looks like you're going the settings key route anyway, but here's what I dug up.

I found a super useful description of how the systemwide date system works: https://sourceware.org/glibc/wiki/Locales. It's not exactly nice...
There are also ways to change the system locale (https://www.gnu.org/software/libc/manual/html_node/Setting-the-Locale.html and https://askubuntu.com/questions/6016/how-to-set-monday-as-the-first-day-of-the-week-in-gnome-calendar-applet/69288#69288) but they can only set the whole time format (change LC_TIME to some other installed locale, like EN_GB), not individual parts of it. I think the only way to modify only the week data would be to compile a new locale with that data modified. Also looks like KDE implemented this at some point, but it may have been a settings key for them too. (I can't tell based on that post) It would be nice if we could do this, so it would work outside of just those 2 apps. (also, aren't we not supposed to access system settings keys in flatpak?) But it may not be feasible, and the settings key would fix probably the most relevant 2 apps.

[lainsce]

I think the only way to do this real-time without having to logon again is the settings key.
Problem is, I need to plan how this will be done, or else it will start becoming messy code.

[lainsce]

It's starting to work:

• Enhancement: Select First Day of Week for Locale #127
• Use First Day of Week Setting from Switchboard Locale Plug panel-datetime#240
• Use First Day of Week Setting from Switchboard Locale Plug calendar#638 (needs some help about the gschema key not being available on CI error)

[marbetschar]

What's the current state of the custom defined start of a weekday in Switchboards locale plug? Is this still something beeing actively worked on?

[lainsce]

I've left it in a working state last I remember

[danirabbit]

Gonna link here that there’s been some movement from GNOME and portals on this feature as well so worth following up to make sure we’re working in a cross platform way https://gitlab.gnome.org/GNOME/gnome-calendar/-/issues/160#note_1872970