Zsh script to generate favicons from an image

create-favicons.zsh

#!/usr/bin/env zsh

VERSION="1.0.0"

print_help() {
  echo "Usage: $0 <input-image>"
  echo ""
  echo "Example:"
  echo "  $0 logo.png"
  echo ""
  echo "Outputs:"
  echo "  favicon.ico        (16x16, 32x32)"
  echo "  favicon_128.png    (180x180)"
  echo "  favicon_144.png    (144x144)"
  echo "  favicon_192.png    (192x192)"
  echo "  favicon_384.png    (384x384)"
  echo "  favicon_512.png    (512x512)"
}

# flags
if [[ "$1" == "-h" || "$1" == "--help" ]]; then
  print_help
  exit 0
fi

if [[ "$1" == "-v" || "$1" == "--version" ]]; then
  echo "$VERSION"
  exit 0
fi

# dependency check
if ! command -v magick >/dev/null 2>&1; then
  echo "Error: ImageMagick (magick) not found."
  echo "Install with:"
  echo "  brew install imagemagick"
  exit 1
fi

INPUT="$1"

if [[ -z "$INPUT" || ! -f "$INPUT" ]]; then
  echo "Error: input file missing or not found."
  print_help
  exit 1
fi

# ICO (multi-size)
magick "$INPUT" \
  -resize 32x32 \
  \( -clone 0 -resize 16x16 \) \
  favicon.ico

# PNG outputs (contain behavior via default resize)
magick "$INPUT" -resize 180x180 -background none -gravity center -extent 180x180 favicon_128.png
magick "$INPUT" -resize 144x144 -background none -gravity center -extent 144x144 favicon_144.png
magick "$INPUT" -resize 192x192 -background none -gravity center -extent 192x192 favicon_192.png
magick "$INPUT" -resize 384x384 -background none -gravity center -extent 384x384 favicon_384.png
magick "$INPUT" -resize 512x512 -background none -gravity center -extent 512x512 favicon_512.png