Script that resizes jpg images to a desired pixel ratio

resize-images.sh

#!/bin/bash

supported_resolutions=("144" "240" "360" "480" "720" "1024") # Supported resolutions
supported_extensions=("png" "jpg" "jpeg") # Supported image file extensions

selected_output_directory=""
# default_output_directory="img"
selected_resolution=""

while [[ $# -gt 0 ]]; do
    case "$1" in
        -r|--resolution)
            shift
            selected_resolution="$1"
            shift
            ;;
        -o|--out-dir)
            shift
            selected_output_directory="$1"
            shift
            ;;
        *)
            echo "Usage: $0 [-r|--resolution <resolution>] [-o|--out-dir <directory>]"
            exit 1
            ;;
    esac
done

if [ -z "$selected_resolution" ]; then # Prompt for resolution if not provided
    while [[ ! " ${supported_resolutions[*]} " =~ " $selected_resolution " ]]; do
        # read -p "Choose a resolution from the available opts (${supported_resolutions[@]}) "  selected_resolution
        read -p "Choose a resolution from the available opts (${supported_resolutions[*]}): " selected_resolution

    done
fi
echo "You chose resolution: $selected_resolution"

create_dir() {
    local dir="$1"

    if [ -d "$dir" ]; then
        echo "Directory '$dir' already exists."
        return 1
    else
        mkdir -p "$dir"
        echo "Created directory '$dir'."
        return 0
    fi
}

if [ -z "$selected_output_directory" ]; then # Prompt for directory if not provided
    while true; do
        read -p "Destination directory: "  selected_output_directory
        if create_dir $selected_output_directory; then
            break
        fi
    done
else
    if ! create_dir $selected_output_directory; then
        exit 1
    fi
fi

# Build the pattern
pattern=""
for ext in "${supported_extensions[@]}"; do
    pattern+="*$ext "
done

# Copy files using the pattern
echo "Copying $pattern files to destination folder ($selected_output_directory)"
cp $pattern "$selected_output_directory"

# Function to resize an image using sips
resize_image() {
    local file="$1"
    sips -Z $selected_resolution "$selected_output_directory/$file" > /dev/null
}

echo "Resizing files to $selected_resolution pixels width..."
# Iterate through the provided arguments (file paths)
for ext in "${supported_extensions[@]}"; do
    for file in *.$ext; do
        if [ -f "$file" ]; then
            # echo "Resizing $file to $selected_resolution pixels width..."
            resize_image "$file"
        fi
    done
done

echo "Done!"