gimp-white-balance

#!/bin/bash
# GIMP White Balance - Apply auto white balance to images
# Usage: gimp-white-balance INPUT_DIR OUTPUT_DIR [PATTERN]

set -e

# Show help if insufficient args
if [ $# -lt 2 ]; then
    cat <<EOF
Usage: gimp-white-balance INPUT_DIR OUTPUT_DIR [PATTERN]

Apply auto white balance (Colors > Auto > White Balance) to all images
in INPUT_DIR and save results to OUTPUT_DIR.

Arguments:
  INPUT_DIR   Directory containing source images
  OUTPUT_DIR  Directory where processed images will be saved
  PATTERN     File pattern to match (default: *.jpg)

Examples:
  gimp-white-balance ./photos ./processed
  gimp-white-balance ./photos ./processed "*.png"

EOF
    exit 1
fi

INPUT_DIR="$1"
OUTPUT_DIR="$2"
PATTERN="${3:-*.JPG}"

# Validate input directory exists
if [ ! -d "$INPUT_DIR" ]; then
    echo "Error: Input directory '$INPUT_DIR' does not exist"
    exit 1
fi

# Create output directory if needed
mkdir -p "$OUTPUT_DIR"

# Get absolute paths
INPUT_DIR=$(cd "$INPUT_DIR" && pwd)
OUTPUT_DIR=$(cd "$OUTPUT_DIR" && pwd)

# Get the directory where this script is located
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

# Find all matching files and process each one
shopt -s nullglob  # Don't fail if no files match
FILES=("$INPUT_DIR"/$PATTERN)
FILE_COUNT=${#FILES[@]}

if [ $FILE_COUNT -eq 0 ]; then
    echo "No files matching pattern '$PATTERN' found in $INPUT_DIR"
    exit 1
fi

echo "Found $FILE_COUNT files to process"

# Process each file
for filepath in "${FILES[@]}"; do
    filename=$(basename "$filepath")
    output_path="$OUTPUT_DIR/$filename"

    echo "Processing: $filename"

    # Run GIMP in headless mode for this single file
    # GIMP 3.0 changes: pass ONE filename, not two; use vector of drawables; use --quit
    /Applications/GIMP.app/Contents/MacOS/gimp-console \
        -i \
        --batch-interpreter plug-in-script-fu-eval \
        -b "(script-fu-use-v3) \
             (let* ((image (gimp-file-load RUN-NONINTERACTIVE \"$filepath\")) \
                    (layers (gimp-image-get-layers image)) \
                    (drawable (vector-ref layers 0))) \
               (gimp-drawable-levels-stretch drawable) \
               (gimp-image-flatten image) \
               (gimp-file-save RUN-NONINTERACTIVE image \"$output_path\"))" \
        --quit 2>&1 | grep -v "^GIMP" | grep -v "^$" || true

    if [ -f "$output_path" ]; then
        echo "  ✓ Saved: $filename"
    else
        echo "  ✗ Failed: $filename"
    fi
done

echo ""
echo "Processing complete. Results saved to: $OUTPUT_DIR"