epson/print_image.sh

#!/bin/bash
set -e
dev=/dev/usb/lp0

image="$(magick "$1" -resize 512x -dither FloydSteinberg -remap pattern:gray50 pbm:- | base64)"
data_header="$(echo "$image" | base64 -d | sed -n '2p')"
data="$(echo "$image" | base64 -d | tail -n +3 | base64)"

hex_size() {
    printf '%04x' "$1" | sed -e 's/\(..\)\(..\)/\\x\2\\x\1/g'
}

size="$(echo "$data" | base64 -d | wc -c)"
size="$(hex_size "$(("$size" + 10))")"
size_x="$(hex_size "$(echo "$data_header" | cut -d' ' -f 1)")"
size_y="$(hex_size "$(echo "$data_header" | cut -d' ' -f 2)")"

# Upload graphics data
printf '\x1D(L' > $dev
printf "$size" > $dev
printf '0p0' > $dev
printf '\1\1' > $dev  # bx, by (1 or 2)
printf '1' > $dev  # color
printf "$size_x" > $dev  # size x
printf "$size_y" > $dev  # size y
echo "$data" | base64 -d > $dev

# Print graphics data
printf '\x1D(L\2\00002' > $dev

# Cut paper
printf '\n\n\n\x1DVA\0' > $dev