[LVGL] Add to change user widget sub component properties without relying EEZ Flow or user actions similar to Squareline Studio Components

[astorun]

Is your feature request related to a problem? Please describe.
User widget creation should allow users to change certain sub widget component settings within properties panel.

Describe the solution you'd like
In Squareline studio, it is as easy to select a user widget sub component within hierarchy panel and change it is properties. Purple colored widget is user created components with selectable sub components, which allows to change their properties independently. Refer to the image below

Describe alternatives you've considered
Currently, the only viable solution is either using eez-flow (which we do not want to implement due to certain firmware requirements) or manually implementing code during runtime. Please consider implement such feature so we can change properties of user widgets within the editor itself easily.

[astorun]

ok so i sat last night and with the help of codex i made some significant update to the 0.27 code. it now behaves very similarly to squareline studio so user widget sub components can be edited selectively now without relying on eez flow.

i also improved some UI sections like live preview of the font in eez UI itself so we dont have to see empty squares for not available characters for some fonts (fontawesome etc.)

i also did some improvements in properties panel and aligned some stuff better and fixed some bugs like clamping some values to allowed lvgl min/max values.

also added folders/subfolders to themes section so it allows to categorize the colors for more cleaner look.

i am gonna test and keep improve it for a few more weeks. if interested i will send a PR once i feel it is stable and improved enough so you can also check the code and approve if you like it.

[mvladic]

I prefer PRs that focus on a single feature at a time. That said, the ability to modify user widget properties at the point of use looks like an interesting feature, and I'd definitely like to review a PR for it. If you could focus on just that feature for now and submit a PR, that would be great. By the way, I'm planning to release 0.27.0 in the next couple of days and have already closed the feature list — from here on I'm only fixing bugs.

[astorun]

Ok I created a separate branch focusing only on user-widget related changes.
https://github.com/astorun/eez-studio/tree/pr/user-widget-customization

Please note that some UI element updates might needs some tweaking to make it work properly since I do also removed some UI related tweaks as well from that branch. So I did not tested this branch separately.

My master branch with all other changes are also located below, including UI tweaks, folder implementation for theme/colors section etc.
https://github.com/astorun/eez-studio/tree/master

Feel free to check it or implement it to origin. Please note that all the code is done with Codex to make it work faster for our implementation so I did not check it manually. However I tested and verified by building and running it extensively. There still could be some bugs, but so far I fixed all I can find during my tests.