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arthur-os/bin/omarchy-transcode-ascii
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#!/bin/bash
# omarchy:summary=Transcode an image into ASCII/Unicode art text
# omarchy:group=transcode
# omarchy:name=ascii
# omarchy:args=<input-image.svg|png> <output-path> [--width <columns>] [--height <rows>] [--mode <braille|block>] [--threshold <percent>] [--invert]
# omarchy:examples=omarchy transcode ascii ~/logo.svg /tmp/logo.txt | omarchy transcode ascii ~/logo.png ~/.config/omarchy/branding/screensaver.txt --width 80
set -o pipefail
usage() {
cat <<'EOF'
Usage: omarchy-transcode-ascii <input-image.svg|png> <output-path> [options]
Transcodes an image into ASCII/Unicode art text.
Options:
-w, --width <columns> Maximum output width in terminal columns (default: 80)
-H, --height <rows> Maximum output height in terminal rows (default: 26)
-m, --mode <braille|block> Output style (default: braille)
-t, --threshold <percent> Pixel threshold from 0-100 (default: 50)
--invert Treat light pixels as the logo instead of dark pixels
--no-trim Preserve surrounding whitespace/background
--help Show this help
EOF
}
width=80
height=26
mode=braille
threshold=50
invert=false
trim=true
image_path=""
output_path=""
while (($# > 0)); do
case "$1" in
--help)
usage
exit 0
;;
-w | --width)
shift
if [[ -z $1 ]]; then
echo "Missing value for --width" >&2
exit 1
fi
width="$1"
;;
--width=*)
width="${1#*=}"
;;
-H | --height)
shift
if [[ -z $1 ]]; then
echo "Missing value for --height" >&2
exit 1
fi
height="$1"
;;
--height=*)
height="${1#*=}"
;;
-m | --mode)
shift
if [[ -z $1 ]]; then
echo "Missing value for --mode" >&2
exit 1
fi
mode="$1"
;;
--mode=*)
mode="${1#*=}"
;;
--block | --blocks)
mode=block
;;
--braille)
mode=braille
;;
-t | --threshold)
shift
if [[ -z $1 ]]; then
echo "Missing value for --threshold" >&2
exit 1
fi
threshold="$1"
;;
--threshold=*)
threshold="${1#*=}"
;;
--invert)
invert=true
;;
--no-trim)
trim=false
;;
--)
shift
break
;;
-*)
echo "Unknown option: $1" >&2
usage >&2
exit 1
;;
*)
if [[ -z $image_path ]]; then
image_path="$1"
elif [[ -z $output_path ]]; then
output_path="$1"
else
echo "Unexpected argument: $1" >&2
usage >&2
exit 1
fi
;;
esac
shift
done
if (($# > 0)); then
while (($# > 0)); do
if [[ -z $image_path ]]; then
image_path="$1"
elif [[ -z $output_path ]]; then
output_path="$1"
else
echo "Unexpected argument: $1" >&2
usage >&2
exit 1
fi
shift
done
fi
if [[ -z $image_path || -z $output_path ]]; then
usage >&2
exit 1
fi
if ! [[ $width =~ ^[0-9]+$ ]] || (( width < 1 )); then
echo "Invalid width: $width" >&2
exit 1
fi
if ! [[ $height =~ ^[0-9]+$ ]] || (( height < 1 )); then
echo "Invalid height: $height" >&2
exit 1
fi
if [[ $mode != "braille" && $mode != "block" ]]; then
echo "Invalid mode: $mode (expected braille or block)" >&2
exit 1
fi
if ! [[ $threshold =~ ^[0-9]+$ ]] || (( threshold < 0 || threshold > 100 )); then
echo "Invalid threshold: $threshold (expected 0-100)" >&2
exit 1
fi
if [[ ! -f $image_path ]]; then
echo "Logo file not found: $image_path" >&2
exit 1
fi
if omarchy-cmd-missing magick; then
echo "ImageMagick is required to convert logo images" >&2
exit 1
fi
case "$mode" in
braille)
pixel_width=$((width * 2))
pixel_height=$((height * 4))
;;
block)
pixel_width=$width
pixel_height=$((height * 2))
;;
esac
alpha_min=$(magick -background none "$image_path" -alpha extract -format '%[fx:minima]' info: 2>/dev/null) || {
echo "Unable to read logo image: $image_path" >&2
exit 1
}
alpha_max=$(magick -background none "$image_path" -alpha extract -format '%[fx:maxima]' info: 2>/dev/null) || {
echo "Unable to read logo image: $image_path" >&2
exit 1
}
use_alpha=false
if awk -v min="$alpha_min" -v max="$alpha_max" 'BEGIN { exit !(min < 0.999 && max > min) }'; then
use_alpha=true
fi
magick_args=(-background none "$image_path" -auto-orient)
if [[ $use_alpha == "true" ]]; then
magick_args+=(-alpha extract -alpha off)
if [[ $invert == "true" ]]; then
magick_args+=(-negate)
fi
else
magick_args+=(-alpha remove -alpha off -colorspace Gray)
if [[ $invert == "false" ]]; then
magick_args+=(-negate)
fi
fi
if [[ $trim == "true" ]]; then
magick_args+=(-bordercolor black -border 1 -trim +repage)
fi
magick_args+=(-resize "${pixel_width}x${pixel_height}" -threshold "${threshold}%" -negate -compress none pbm:-)
tmp_output=$(mktemp)
trap 'rm -f "$tmp_output"' EXIT
if [[ $mode == "braille" ]]; then
if ! magick "${magick_args[@]}" | awk '
BEGIN {
braille_base = 10240
dot[0,0] = 1
dot[0,1] = 2
dot[0,2] = 4
dot[1,0] = 8
dot[1,1] = 16
dot[1,2] = 32
dot[0,3] = 64
dot[1,3] = 128
}
{
sub(/#.*/, "")
for (i = 1; i <= NF; i++) {
token[++token_count] = $i
}
}
END {
if (token[1] != "P1") {
exit 1
}
width = token[2]
height = token[3]
pixel_offset = 4
for (y = 0; y < height; y += 4) {
line = ""
for (x = 0; x < width; x += 2) {
code = 0
for (dy = 0; dy < 4; dy++) {
for (dx = 0; dx < 2; dx++) {
if (y + dy < height && x + dx < width) {
pixel = token[pixel_offset + ((y + dy) * width) + x + dx]
if (pixel == 1) {
code += dot[dx,dy]
}
}
}
}
if (code == 0) {
line = line " "
} else {
line = line sprintf("%c", braille_base + code)
}
}
sub(/[ ]+$/, "", line)
lines[++line_count] = line
}
first = 1
while (first <= line_count && lines[first] ~ /^[ ]*$/) {
first++
}
last = line_count
while (last >= first && lines[last] ~ /^[ ]*$/) {
last--
}
for (i = first; i <= last; i++) {
print lines[i]
}
}
' >"$tmp_output"; then
echo "Unable to convert logo image: $image_path" >&2
exit 1
fi
else
if ! magick "${magick_args[@]}" | awk '
BEGIN {
block["11"] = "█"
block["10"] = "▀"
block["01"] = "▄"
block["00"] = " "
}
{
sub(/#.*/, "")
for (i = 1; i <= NF; i++) {
token[++token_count] = $i
}
}
END {
if (token[1] != "P1") {
exit 1
}
width = token[2]
height = token[3]
pixel_offset = 4
for (y = 0; y < height; y += 2) {
line = ""
for (x = 0; x < width; x++) {
top = token[pixel_offset + (y * width) + x]
bottom = (y + 1 < height) ? token[pixel_offset + ((y + 1) * width) + x] : 0
line = line block[top bottom]
}
sub(/[ ]+$/, "", line)
lines[++line_count] = line
}
first = 1
while (first <= line_count && lines[first] ~ /^[ ]*$/) {
first++
}
last = line_count
while (last >= first && lines[last] ~ /^[ ]*$/) {
last--
}
for (i = first; i <= last; i++) {
print lines[i]
}
}
' >"$tmp_output"; then
echo "Unable to convert logo image: $image_path" >&2
exit 1
fi
fi
if [[ ! -s $tmp_output ]]; then
echo "No logo pixels found in: $image_path" >&2
exit 1
fi
mkdir -p "$(dirname "$output_path")"
cp "$tmp_output" "$output_path"
echo "Wrote ASCII art to $output_path"