Allow a theme to override the form factor of the tabs to be mobile

[andydotxyz]

This avoids being forced to respect the singleton device reported from hardware

Opening for discussion about this use for the Size callback avoiding a breaking change or new API requirement for a "theme feature".

Also test to follow.

Checklist:

• Tests included.
• Lint and formatter run with no errors.
• Tests all pass.

[coveralls]

coverage: 59.962% (+0.001%) from 59.961%
when pulling d0421e6 on andydotxyz:feature/simulatemobiletheme
into de361f6 on fyne-io:develop.

[dweymouth]

I think a new API would be much cleaner than overriding the meaning of Size in themes like this

[andydotxyz]

I think a new API would be much cleaner than overriding the meaning of Size in themes like this

What would such an API be like? Would it be an optional extension? The part that I'm not sure about is that some sort of "config" section could be all sorts of types int/bool/float/string...

[dweymouth]

I think a new API would be much cleaner than overriding the meaning of Size in themes like this

What would such an API be like? Would it be an optional extension? The part that I'm not sure about is that some sort of "config" section could be all sorts of types int/bool/float/string...

I guess I need to know more about the planned use cases. If this is just about the tabs widget, I would just add a new property API to AppTabs and DocTabs to control this, similar to the Orientation property of RadioGroup and CheckGroup. If it's about overriding device settings in general, maybe a new set of APIs related to device and not the theme? If it's about general, open-ended settings that are tied to the theme, then some more API design may be needed (and more use case discovery to guide the API design)

[andydotxyz]

It's not the same thing as orientation, as the tabs respond differently on different platforms rather than just switch configuration.
If the options are exposed separately then something overriding the context becomes tied to the render implementation for AppTabs.

I wonder if it could instead be an api on ThemeOverride if being on theme isn't looking like a good approach?
It would probably still need to be passed internally through theme or a whole new cache that indexes on theme. I was trying to keep it simple by passing it in Size but I'll keep thinking.

[andydotxyz]

This was merged by mistake somehow. The commit was reverted on develop and re-applied on this branch so the conversation can continue where we left off.