I already thought this many times.
Last year, I bought a 1.14" 135x240 ST77889 display for testing.
I modified, improved and
released a driver/graphic library for it making use of stm32 DMA, achieving prettty nice speeds.
Anyways, there're several reasons I decided to not do it:
- It's a lot of work, specially if I have to add every display/driver anyone requests. Also, I would have to buy the display for the development.
- The graphics driver would need to be done completely, there's no RAM for buffering, all operations need to be done at pixel level over the lcd interface.
- Even if using DMA, driving a colour LCD over SPI is usually pretty slow, specially ksgers using stm32F101 (36MHz). Only DMA transfers (image/block filling) achieves acceptable speeds, fonts are way slower, specially big fonts.
(Have you seen those arduinos refreshing the display at 2FPS? No thanks!)
- Wasn't happy with the performance/image quality, redrawing usually causes tearing effect or glitches due the interface slowness.
Most of these displays can't be read over 3-wire SPI, so forget transparency. Also most don't have Tearing Effect output to minimize the tearing.
- It would be a lot of work just for a minority of users.