[yocto] Building your own UI

[autif khan]

>>> This may be a dumb question, but I'll ask anyway.
>>
>>> Suppose you have a project where you need a very custom user
>>> interface. Not just a series of applications that appear on a desktop
>>> like you see in sato, or Gnome, or KDE.  Basically your application
> becomes the UI.
>>
>>> I can see 2 approaches to this:
>>
>>> Start with core-image-minimal and add the packages you need to support
>>> GFX, X11, and your application plus dependencies.
>>> Take core-image-sato and change the applications to be your subtasks ,
>>> and the look-and-feel of the desktop.
>>
>>> What are the considerations of both approaches?
>> >Is one better, or easier than the other?
>> >How would you do this in Yocto?
>>> Where do you look for information you need to accomplish this?
>
>>We are still in the very early stages of architecture design and
> development
>
>>For now we are leaning towards keeping everything that comes with
> core-image-sato and writing a full screen app on top of it. Likely to be
> written in .NET (mono). A prototype (proof of concept) has been successfully
> developed :-)
>
>>As I said - still in very early stages of arch/design and dev. So things
> may still change.
>
>
> If it is okay to jump in an comment, I was going to ask the same question at
> some point.
>
> The need to have the application as the main UI or shell to the system is
> important for branding. Launching sato or other desktop would not be
> desirable. As an example, Windows uses Explorer.exe as the shell, but can be
> replaced with any application. Windows was architected this way. It would be
> nice to have similar architecture here, but I know it is easier said than
> done. As you said this is early in design.

We do have a lot of open questions that we will answer in good time:

1) Should the application be executed as root or as some user or as nobody

2) Should we trim the image? (we are not short on space or ram)

3) Aforementioned - should the app run from inittab or rcS.d or something else

We will figure out these things when we are on that bridge.

I do have a question - you have provided the example of Windows -
where explorer is the shell and can be changed. However, there is no
argument here - what are the clear (no brainer) or subjective
arguments for one versus the other.