Display driver that sends the framebuffer to UVC

[josuah]

Is your feature request related to a problem? Please describe.

in Zephyr, LVGL assumes a display driver present.

• LVGL can be used to draw an overlay on top of a video feed.
• UVC can be used as a way to debug an LVGL device.
• This also allows non-video usage of UVC such as plot data like a spectrogram.

Describe the solution you'd like

A driver that implements the display API. The .write() API call updates a local framebuffer periodically sent to UVC.

Describe alternatives you've considered

This might require to memcpy() a lot of data every time write() is called.

For the use-case of drawing to a video background, an extra API could be introduced to replace the framebuffer by the input video frame, to then have LVGL draw again on top. The video feed would have the status of "background image".

[josuah]

The extra API to update the framebuffer can then be a video API: an input queue of video frames, an output queue with video frames with an UI drawn on top.

Remain to understand if LVGL supports re-writing everything every frame as well as a background that is not a solid color but an image.