Cant get display to show

[kiasarecool]

Cant get display to show

[niko001]

I had a blank (white) screen as well, in my case I believe this had to do with the different color space of my Black/White/Red inkyPHAT screen compared to the Black/White version.

How I fixed it:

• Make sure imagemagick is installed:
  sudo apt-get install imagemagick

• Copy the InkypHAT-250x122.png example file from the inky library to the inkystock/data/ directory

• Save the following code as convert.py to the inkystock/inkystock/ subdirectory

#!/usr/bin/env python3
# Modified from https://github.com/RubenLagrouw/inkyconv
from os import remove
from PIL import Image as PILImage
import subprocess

class Convert:
	
    def convert(imgpath, outpath, example='data/InkypHAT-250x122.png', dimensions=(250, 122)):
        subprocess.run(
             'convert {in_file} -auto-orient -geometry {x}x{y}^ -gravity center -crop {x}x{y}+0+0 -strip -type Palette -remap {ex} -dither FloydSteinberg temp.png'
            .format(in_file=imgpath, x=dimensions[0], y=dimensions[1], ex=example), shell=True)
    
        img = PILImage.open("temp.png")
        cR = [255, 0, 0]
        cB = [0, 0, 0]
        cW = [255, 255, 255]
    
        new_pixdata = []
        old_pixdata = img.getdata()
        palette_old = img.getpalette()
    
        if palette_old == None: # Grayscale Image
    
          for pix in old_pixdata:
            if pix == 0:
              new_pixdata.append(0)
            else:
              new_pixdata.append(1)
          img = PILImage.new("P", dimensions)
    
        else: # Coloured Image
    
            p_conv = {0: palette_old[0:3],
                    1: palette_old[3:6],
                    2: palette_old[6:9]}
    
            for pix in old_pixdata:
                if pix not in p_conv:
                    print('Pixel out of range: {}'.format(pix))
                    new_pixdata.append(0)
                elif p_conv[pix] == cW:
                    new_pixdata.append(0)
                elif p_conv[pix] == cB:
                    new_pixdata.append(1)
                elif p_conv[pix] == cR:
                    new_pixdata.append(2)
    
        img.putdata(new_pixdata)
        img.putpalette(cW + cB + cR)  # Goal palette
    
        remove('temp.png')
        if not outpath.lower().endswith('.png'):
            outpath += '.png'
        img.save(outpath)
        return 0
    
    if __name__ == '__main__':
        import sys
        if len(sys.argv) != 3:
            print('Improper amount of arguments')
            sys.exit(-1)
        convert(sys.argv[1], sys.argv[2])

• In inkystock/inkystock/paint.py, add the following methods to the Pillow class:

class Pillow(Painter):
    def open(self, path):
    	  return PILImage.open(path)

    def display_no_invert(self, image: PillowImage):
        board = auto()
        board.set_image(image)
        board.show()

• In inkystock/main.py, import the new convert.py class:
  from inkystock.convert import Convert

• At the end of the main() method, change
  image.render().save(config.outputs.local)
  to
  image.invert().render().save(config.outputs.local)

• After that line, add the following:

    # Correct the color space of the image
    Convert.convert(config.outputs.local, "./data/out_converted.png")
    img = painter.open("./data/out_converted.png")

• Change painter.display(image) to painter.display_no_invert(img)

This will covert the locally saved PNG file (data/out.png) to the correct color space using ImageMagic and then display the converted file on the inkyPHAT. I'm sure there is a better/easier solution, but this works :)

[duggan]

It's interesting that you've had this problem with an Inky display – after checking the supplier it looks like they've updated the display since I last bought some, which may account for the problems you're seeing:

We started rolling out a higher resolution SSD1608 e-paper screen on Inky pHAT from late 2020 (250x122 pixels instead of 212x104!). These new screens require different drivers, but the library should autodetect the right drivers for your screen. You might run into problems using third party software to drive the display if you have one of these newer boards.

 I'll probably get one of the newer displays (because shiny new stuff!) but will take a look at the code for the new displays either way, there may be some fairly simple changes to make to correct the issue.

[duggan]

Think this should be fixed now!