Send images to RA8875 it's a slow business? yes, but there's a (complicated) way...

The RA8875 it's probably the most complex display controller in it's category, it's has been designed to be a monolitic GUY interface all featured without use MCU resources but it doesn't have a way to fill inside memory apart geometric macros, this cause a big bottleneck when user try to send images instead to write geometric stuff. Send a full color image to fill the screen can take even more than a minute in this way in contrast to every other command that almost instantly drive on screen thanks to hardware accellerated graphics!
After hours of searching I found a way to send rows that accellerate a bit but can be a solution using it's BTE engine, something I have to test...
RAIO introduced an external SPI bus that let RA8875 chip drive several SPI devices standalone at very high speed using optimized code completely transparently.
Some chinese vendor included this feature in their design (like Eastrising) but this is totally absent in other products like Adafruit, the main reason it's simple, you need to fill the chip with image data before solder it so it's clearly not an easy procedure for a DIY enthusiast.
If you have this feature in your display and you want to experiment here's a simple wiki but beware because you will need some extra stuff and a lot of patience!
If you got an EastRising display and you get the SPI Flash RAM chip, DO NOT SOLDER it yet! You have to feed the SPI chip with some image first (and write down the start address and lenght of any image)...

..coming up