Allow/Encourage Dithering

[jezs00]

Should be able to get some better looking images on EPDs using dithering. https://github.com/robweber/omni-epd/wiki/Image-Dithering-Options

Considerations: Operations will probably be computationally heavy. Need to balance with battery life.

Realistically the option is already implemented as omni-epd already eats the config file, but if it makes the image look better it is worth putting into the readme and default config. So:

• Test out a few different dithering options with color EPD
  • Gauge processing time, whether it looks good
• Add best looking dither algorithm to .config-example

[recrudesce]

This'll help dramatically. It makes a lot of difference on the Inky Impression I have here:

https://github.com/pimoroni/inky/blob/master/examples/7color/advanced/dither.py

[jezs00]

This looks great. I'll try and default one that is quick but looks good.

On Wed, 25 Jan 2023, 11:32 am recrudesce, @.***> wrote:

This'll help dramatically. It makes a lot of difference on the Inky Impression I have here:

https://github.com/pimoroni/inky/blob/master/examples/7color/advanced/dither.py

— Reply to this email directly, view it on GitHub https://github.com/jezs00/pycasso/issues/33#issuecomment-1402879856, or unsubscribe https://github.com/notifications/unsubscribe-auth/AUTEK7G3JSOMFVP2Q43JQ3LWUBYCRANCNFSM6AAAAAAUCGWXJA . You are receiving this because you authored the thread.Message ID: @.***>

[recrudesce]

So I added the dithering option to the config and adjusted the config_wrapper to pull the setting into the config dict, but once again all images are turning into black and white images. It's weird, it's like it has a problem with the config and is reverting back to default settings.

I probably did something wrong :P

[recrudesce]

OK, fixed it really easily.

in .config, add the following line under the [EPD] section (this is for 7 colour displays) palette_filter=[[0, 0, 0], [255, 255, 255], [0, 255, 0], [0, 0, 255], [255, 0, 0], [255, 255, 0], [255, 128, 0]]

then under the [Display] section, add dither=floydsteinberg

It should just work.

[jezs00]

Looks really good. I'll look at setting up some of these defaults today and just make sure it's not taking too long.

adjusted the config_wrapper to pull the setting into the config dict,

FYI you shouldn't need to modify config_wrapper for any omni-epd options as that class just consumes the entire config and reads the dict itself.

[jezs00]

Wow I just tested it out and it does make things look much better, and according to the log, the floydsteinberg dithering is fast. I will put the dithering options in config-example but leave them commented out.

[jezs00]

Closing issue. Can't believe I've gone this long without dithering!