Feature: Added proper support for RTL languages

[XTorLukas]

Resolved / Related Issues

To prevent extra work, all changes to the Files codebase must link to an approved issue marked as Ready to build. Please insert the issue number following the hashtag with the issue number that this Pull Request resolves.

• From Feature: RTL interface #16477
• From File properties page does not support RTL #2786

Microsoft issues

• From Can not make RTL language application in WinUI 3 microsoft/microsoft-ui-xaml#8746
• From ContentDialog FlowDirection does not follow the XamlRoot.Content FlowDirection microsoft/microsoft-ui-xaml#9899

Steps used to test these changes

Stability is a top priority for Files and all changes are required to go through testing before being merged into the repo. Please include a list of steps that you used to test this PR.

Important

This service function is only used to display the layout correctly.

1. Opened Files
2. Set RTL or LTR culture
3. Automaticaly change flow direction layout

Tests for RTL

• All Dialogs show correctly
• All Tooltip show correctly
• All Windows show correctly
• All Drag position works correctly
• Forward & Back swipe in touchscreen works correctly
• Position dragging works correctly on MainProperties page
• Tab action button is clickable

[XTorLukas]

fyi @0x5bfa

[0x5bfa]

Looks great. Does this also work for generated content dialogs such as the add new dialog that is shown when Ctrl+Shift+I entered?

[marcelwgn]

Thank you for all the effort you put into this PR @XTorLukas. I think it is a good step forward and good you made these investigations, I think there are a few things I would approach differently for this.

The approach with the code generator is quite interesting, however it seems quite complicated to what we would like to achieve here. From what I can see, there are three things we need to do to properly support RTL:

1. Update the caption buttons to be on the left in RTL
2. Set the FlowDirection of the MainPage to RTL
3. Get ContentDialogs to respect our RTL layout

While your approach does achieve this, it also creates a lot of complexity through the interfaces and the code generators associated with them. I would probably prefer a lightweight FlowDirectionService that essentially provides the following API:

1. A property called FlowDirection that you can bind to (and a function generating bindings for it in code behind)
2. A method to update the state from LTR to RTL (and vice versa) which sets the correct flags to update the titlebar/caption buttons and sets the FlowDirection property (which updates the bindings)

An open question for me (and something that is also not addressed in this PR right now I think) is how to deal with m

ultiple windows. Does every window have its own FDS? How do all of these get notified of the change?

Edit: Attached is a test version I used for testing RTL stuff FlowDirectionManager.txt