ImageMagick Guide

Create TRMNL-friendly images.

TRMNL supports BMP3 and PNG images natively, starting with FW v1.5.2. Below are some tips to generate TRMNL compatible images for DIY devices or Alias/Redirect plugin applications.

Generating a BMP3 image

Convert command

magick input.png -monochrome -colors 2 -depth 1 -strip bmp3:output.bmp

Identify command

% magick identify output.bmp 
output.bmp BMP3 800x480 800x480+0+0 1-bit sRGB 2c 48062B 0.020u 0:00.001

Please note that the output of above needs to match exactly with your file.

Generating a PNG image (1 bit)

Converting an image

magick input.png -monochrome -colors 2 -depth 1 -strip png:output.png    

Dithering an image

magick input.png -dither FloydSteinberg -remap pattern:gray50 -depth 1 -strip png:output.png

Identify command

% magick identify output.png 
output.png PNG 800x480 800x480+0+0 8-bit Grayscale Gray 2c 1607B 0.000u 0:00.000

Generating a PNG image (2 bit)

This feature is experimental and designed for OG model devices running FW 1.6.0+ with grayscale + fast refresh support. After creating an image, upload it to a public or private/local network and point to it with an Alias plugin instance.

First create a color map:

magick -size 4x1 xc:#000000 xc:#555555 xc:#aaaaaa xc:#ffffff +append -type Palette colormap-2bit.png

Then convert your image with the map:

magick input.jpeg -resize 800x480\! -dither FloydSteinberg -remap colormap-2bit.png -define png:bit-depth=2 -define png:color-type=0 output.png