Batch image file convert script

gistfile1.txt

#!/usr/bin/env bash
# ------------------------------------------------------------
# batch_image_convert.sh – batch‑scale images and set 72 dpi.
# Supports: HEIC, JPG/JPEG, PNG → always saved as JPG.
#
# Options:
#   -d <dir>   Source directory (default: current directory)
#   -s <pct>   Resize percentage (e.g. 25%). Default: 50%
# ------------------------------------------------------------

set -euo pipefail   # safer scripting

# ---------- Default configuration ----------
SRC_DIR="."                     # default = current working directory
OUT_SUBDIR="converted"          # name of the output sub‑folder
DPI=72                          # target DPI
DEFAULT_SCALE="50%"             # fallback when -s is not given
QUALITY=85                      # JPEG quality (good web default)

# ---------- Helper / usage ----------
usage() {
    cat <<EOF
Usage: $(basename "$0") [-d <source_dir>] [-s <scale_pct>]

Options:
  -d <source_dir>   Directory containing the images to convert.
                    If omitted, the script uses the current directory (".").

  -s <scale_pct>    Resize factor, expressed as a percentage (e.g. 25%).
                    Must end with a percent sign. Default is 50%.

The script creates a sub‑folder named "$OUT_SUBDIR" inside the source
directory and writes the converted JPEG files there.
EOF
    exit 1
}

# ---------- Parse command‑line arguments ----------
SCALE="$DEFAULT_SCALE"   # initialise with default

while getopts ":d:s:h" opt; do
    case "$opt" in
        d) SRC_DIR="${OPTARG}" ;;
        s)
            # Basic validation – must contain a trailing %
            if [[ "${OPTARG}" != *% ]]; then
                echo "Error: -s argument must end with a % sign (e.g. 30%)." >&2
                usage
            fi
            SCALE="${OPTARG}"
            ;;
        h) usage ;;
        \?) echo "Invalid option: -${OPTARG}" >&2; usage ;;
        :)  echo "Option -${OPTARG} requires an argument." >&2; usage ;;
    esac
done
shift $((OPTIND-1))

# Resolve ~ and relative paths to an absolute path
SRC_DIR="$(realpath -m "$SRC_DIR")"
OUT_DIR="${SRC_DIR}/${OUT_SUBDIR}"

# ---------- Locate ImageMagick executable ----------
if command -v magick >/dev/null 2>&1; then
    IM_CMD="magick"
elif command -v convert >/dev/null 2>&1; then
    IM_CMD="convert"
else
    echo "Error: Neither 'magick' nor 'convert' (ImageMagick) is found in your PATH."
    echo "Install it with: sudo apt-get install imagemagick libheif-examples"
    exit 1
fi

# ---------- Check HEIC support (once) ----------
if $IM_CMD -list format | grep -iq '^[[:space:]]*HEIC'; then
    HAVE_HEIC=1
else
    HAVE_HEIC=0
    echo "Warning: ImageMagick on this system does NOT have HEIC support."
    echo "HEIC files will be skipped. To add support, run:"
    echo "  sudo apt-get install libheif-dev"
    echo "  sudo apt-get purge imagemagick"
    echo "  sudo apt-get install imagemagick"
fi

# Create output directory if it doesn't exist
mkdir -p "$OUT_DIR"

# ---------- Process images ----------
shopt -s nullglob nocaseglob
for img in "$SRC_DIR"/*.{heic,jpg,jpeg,png}; do
    [[ -f "$img" ]] || continue   # skip non‑files

    # Skip HEIC files only when we truly lack support
    if [[ "${img,,}" == *.heic ]] && (( HAVE_HEIC == 0 )); then
        echo "Skipping HEIC (no support): $img"
        continue
    fi

    base_name="$(basename "${img%.*}")"   # strip directory & extension
    out_path="${OUT_DIR}/${base_name}.jpg"

    # Run the conversion/resizing
    $IM_CMD "$img" \
        -resize "$SCALE" \
        -density "$DPI" \
        -units PixelsPerInch \
        -quality "$QUALITY" \
        "$out_path"

    echo "Converted → $out_path"
done
shopt -u nullglob nocaseglob

echo "All done! Converted images are in '${OUT_DIR}'."