How to prepare Bitmaps for Tri-Color E-Ink Displays?

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tamberg
 
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Joined: Wed May 07, 2014 1:09 pm

How to prepare Bitmaps for Tri-Color E-Ink Displays?

Post by tamberg »

Hi, your E-Ink tutorials, e.g. https://learn.adafruit.com/adafruit-cir ... ng-bitmaps contain bitmap images, e.g. https://cdn-learn.adafruit.com/assets/a ... 1614110318 that work well with Tri-Color E-Ink displays like https://www.adafruit.com/product/4869

However, if I open the same bitmap on MacOS, modify it (e.g. flip horizontally), and save it again, the resulting bitmap cannot be displayed. I checked the image size, resolution and depth. Is there another image attribute that could be different? One thing that seems odd is the file size, the original is 120 KB, the copy is 160 KB.

Kind regards,
Thomas

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rpiloverbd
 
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Joined: Mon Nov 29, 2021 8:13 am

Re: How to prepare Bitmaps for Tri-Color E-Ink Displays?

Post by rpiloverbd »

Hello, For monochrome e-paper display, I used image2LCD. It had options for coloured displays also. Is it of any help to you? https://www.waveshare.com/wiki/File:Image2Lcd.7z

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tamberg
 
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Re: How to prepare Bitmaps for Tri-Color E-Ink Displays?

Post by tamberg »

Thanks. Got it to work on MacOS using imagemagick as described in https://learn.adafruit.com/preparing-gr ... mmand-line but with -compress None BMP3, e.g.

Code: Select all

$ convert input_200x200.jpg -dither FloydSteinberg -define dither:diffusion-amount=85% -remap eink___epaper_eink-3color.png -compress None BMP3:output_200x200.bmp

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sipan1313
 
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Re: How to prepare Bitmaps for Tri-Color E-Ink Displays?

Post by sipan1313 »

hello
Because E-ink displays typically offer just a few shades, 1- or 4-bit output would normally be ideal. But due to the library constraints above, sometimes it’s necessary to use 24-bit output regardless.
so try to Convert With ImageMagick

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