Display: LVGL: Monochromatic: Option to vertically stack 8-bit bytes in screen buffers

[alen-daniel]

Introduction

For LVGL monochromatic displays, I am seeking thoughts on how to go about implementing vertically stacked 8-bit byte screen buffers

Problem description

Note: I am using the word "length" to indicate the longer dimension and "width" to indicate the shorter dimention of a rectangular display.

Context: I am using an SPI monochromatic display (example: https://display.kyocera.com/tn0216anvnann-gn00) that can only write 1 line at a time along the length direction of the LCD.

Problem: I am unable to use the Zephyr display drivers with lvgl to display in the portrait orientation (x axis is width, y axis is length of the LCD)

When I use the Zephyr display drivers for monochromatic display, this works fine if I want to display LVGL buffers in the landscape orientation, because the LVGL buffers are generated with 8-bit bytes stacked horizontally along the length direction.

But I am unable to use this to display in the portrait orientation. In portrait orientation, the LVGL buffers are generated with 8-bit bytes stacked horizontally in the width direction, but the LCD requires the buffers to be stacked vertically in the length direction.

Proposed change

For monochromatic displays using LVGL, add an option to generate screen buffers that are 8-bit bytes stacked vertically

Request for Comment

I seek feedback from the contributing community on how to go about doing this.