Another display for nano-gui

[beetlegigg]

I've been using a couple of 480x480 displays, one is the Presto from Pimoroni, and the other is the Squixl from The Unexpected Maker. They both have screen drivers where whatever is drawn to the framebuffer is immediately shown on the display and its not necessary for the micropython program to assign SPI or i2c pins etc.

Both these displays can use the nano gui and I show the color_setup.py for the Presto

"""
to set up Presto to use CWriter and font_to_py fonts
this setup also works for nano_gui

"""

import framebuf
from presto import Presto
from boolpalette import BoolPalette

class WriterDevice(framebuf.FrameBuffer):
    def __init__(self, buffer):
        self.width = 480
        self.height = 480
        self.buffer = buffer
        self.mode = framebuf.RGB565
        self.palette = BoolPalette(self.mode)
        super().__init__(self.buffer, self.width, self.height, self.mode)
        
    def show(self):
        ...
        
    @staticmethod
    def rgb(r, g, b):
        return (r & 0xF8) | (g & 0xE0) >> 5 | (g & 0x1C) << 11 | (b & 0xF8) << 5


presto = Presto(full_res=True, palette=False, direct_to_fb=True)
fb = framebuf.FrameBuffer(presto.buffer, 480, 480, framebuf.RGB565)

ssd = WriterDevice(fb)
SSD = ssd

touch = presto.touch

Of course the touch on these screen does nothing when using nano-gui but I have also been simply using the CWriter as found in the Fonts-to-py to write text to these displays and I've created some widgets by directly using the framebuffer routines. The rgb function in the above color_setup has been stolen from the nano-gui to use with the CWriter when not using the rest of nano-gui. These home brewed widgets can use the touch drivers of these displays to map touch coordinates to the screen coordinates of the widgets. I find these displays to be an ideal size to put under a computer monitor for information displays and they can readily be prodded by a fat finger for push button action etc.

Using the frambuffer routines I have a produced a nice compass widget but sadly I've not conquered the use of complex numbers as used in nano-gui to get that very nice arrow pointer dial needle. My needle looks like a demented saxon era sword.

Anyway this is just a note that the good old nano-gui can easily be make to work on these two 480x480 displays :-)