convert-images.sh

#!/bin/bash

DEFAULT_QUALITY=80

# Check if quality values are passed as arguments, if not, use the default
AVIF_QUALITY=${1:-$DEFAULT_QUALITY}
WEBP_QUALITY=${2:-$AVIF_QUALITY}

INPUT_DIR="assets/images"
CSV_FILE="conversion_report-$AVIF_QUALITY-$WEBP_QUALITY.csv"
echo "Image,File Extension,Original Size (bytes),AVIF Savings (%),WebP Savings (%),AVIF vs WebP Difference (%),AVIF Size (bytes),WebP Size (bytes),AVIF Size Difference (bytes),WebP Size Difference (bytes),avifenc output,cwebp output" > "$CSV_FILE"

# OS-specific stat command
if [[ "$OSTYPE" == "linux-gnu"* ]]; then
    STAT_CMD="stat --format=%s"
elif [[ "$OSTYPE" == "darwin"* ]]; then
    STAT_CMD="stat -f %z"
else
    echo "Unsupported OS: $OSTYPE"
    exit 1
fi

sanitize_output() {
    local raw_output="$1"
    echo "$raw_output" | tr '\n' ' ' | tr '\r' ' ' | tr '\t' ' ' | sed 's/"/""/g'
}

for img in "$INPUT_DIR"/*.{png,jpg,jpeg}; do
    if [[ -f "$img" ]]; then
        extension="${img##*.}"

        original_size=$($STAT_CMD "$img")

        avif_output=$(avifenc -q "$AVIF_QUALITY" "$img" "$img.avif" 2>&1)
        avif_size=$($STAT_CMD "$img.avif")

        avif_size_diff=$((original_size - avif_size))
        avif_savings_percentage=$(awk "BEGIN {printf \"%.2f\", ($avif_size_diff / $original_size) * 100}")

        webp_output=$(cwebp "$img" -q "$WEBP_QUALITY" -o "$img.webp" 2>&1)
        webp_size=$($STAT_CMD "$img.webp")

        webp_size_diff=$((original_size - webp_size))
        webp_savings_percentage=$(awk "BEGIN {printf \"%.2f\", ($webp_size_diff / $original_size) * 100}")

        avif_webp_difference=$(awk "BEGIN {printf \"%.2f\", (($webp_size - $avif_size) / $original_size) * 100}")

        sanitized_avif_output=$(sanitize_output "$avif_output")
        sanitized_webp_output=$(sanitize_output "$webp_output")

        echo "\"$img\",$extension,$original_size,$avif_savings_percentage%,$webp_savings_percentage%,$avif_webp_difference%,$avif_size,$webp_size,$avif_size_diff,$webp_size_diff,\"$sanitized_avif_output\",\"$sanitized_webp_output\"" >> "$CSV_FILE"

        echo "Converted $img to AVIF (quality $AVIF_QUALITY) and WebP (quality $WEBP_QUALITY), AVIF savings: $avif_savings_percentage%, WebP savings: $webp_savings_percentage%, AVIF vs WebP difference: $avif_webp_difference%"
    fi
done

echo "Conversion report saved to $CSV_FILE"