ImageMagick Guide
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.png -dither FloydSteinberg -remap colormap-2bit.png \
-define png:bit-depth=2 output.png
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