[Feature Request] Can you expose more UI elements via style.css?

[WheresWaldo]

We are using OctoPrint-TFT in a distribution aimed at the Robo3D printer community. Robo3D has basically abandoned support for their R2 and C2 printers and have not updated their user interface or any of the other Raspberry Pi software used to control their printer in almost two years. The community is involved in trying to provide an open source alternative to the RoboOS default. We have a git repository here https://github.com/WheresWaldo/CommunityOS. It is being built on a customized base of OctoPrint and includes OctoPrint-TFT as part of the build. We are using GuySoft's CustomPiOS to build out images.

Now the issues we are having are all display based, the Robo3D C2 printer uses a 3.5" 480x320 TFT screen and the interface scaling is pretty good, since that appears to be the default you are building to. But the Robo3D R2 printer uses a 5" 800x480 TFT screen and here is where we have issues. Here is a list of what we have observed:

1. Icons seem to scale a bit small and the text can be nearly unreadable for icon labels.
2. The system screen has text that is too small.
3. The status screen text is too small as well as the progress bar in the middle of the screen and the buttons are too high on the screen.
4. The file list screen is almost unreadable and all the buttons in turn are very tiny.
5. On the temperature screen the status panel could use text that is at least double the current size.
6. The filament screen has the same issues with the status panel that the temperature screen has.

We did look at other alternatives to control the build in screen, including trying to fix Robo3D existing code. They are not as receptive to OSS and have not responded when requests are made for their current source code. We also looked at providing TouchUI as an alternative, but deployment for it is a bit to heavy with respect to resources. As well as much harder to preconfigure. We are looking for ways to make OctoPrint-TFT more screen friendly and if these things could be accomplished with a modified style.css we are more than willing to maintain our own copies of that file.

I also know that you have asked GuyS to include OctoPrint-TFT in his OctoPi image, maybe if he sees the way we have integrated it into our image it will incentivize him to add it in the future.