Slice Print and Play pages into individual images.

pnp_slicer.sh

#!/bin/bash

### Using ImageMagick, slices an image in equal parts according to coordinates and column/row numbers
### Useful when slicing images from Print and Play games to later feed to Online Print services

# This is super badly written. Will revise later
function help() {
    echo
    echo "$(basename $0) -h INT -w INT -H INT -V INT -c INT -r INT -i FILE/DIR -o DIR [-f FILE]"
    echo "$(basename $0) -C INTxINT+INT+INT -c INT -r INT -i FILE/DIR -o DIR [-f FILE]"
    echo
    echo "Mandatory Options"
    echo -e "-h\t--height\t\t\tSliced image height"
    echo -e "-w\t--width\t\t\t\tSliced image width"
    echo -e "-V\t--vertical_offset\t\tInitial vertical offset from the border"
    echo -e "-H\t--horizontal_offset\t\tInitial horizontal offset from the border"
    echo -e "-c\t--columns\t\t\tNumber of columns of images"
    echo -e "-r\t--rows\t\t\t\tNumber of rows of images"
    echo -e "-i\t--input\t\t\t\tInput file or directory"
    echo -e "\t\t\t\t\t(will run for each image in the directory if directory)"
    echo -e "-o\t--output_dir\t\t\tOutput directory."
    echo
    echo "Optional Options"
    echo -e "-C\t--coordinates\t\t\tPass a string in 'HEIGHTxWIDTH+HORIZONTAL_OFFSET+VERTICAL_OFFSET' format"
    echo -e "-o\t--output_filename\t\tOutput filename. Will assume 'sliced' if ommited."
    echo -e "\t--verbose\t\t\tEnable imagemagick verbosity"
    echo -e "\t--debug\t\t\t\tDebug mode, print variables and commands and not execute them"
    echo -e "\t--help\t\t\t\tDisplays this help"
}

# Control Variables
ren="^[0-9]+$"
re_coord="^[0-9]+x[0-9]+\+[0-9]+\+[0-9]+$"
counter=1

if [[ $# -eq 0 ]]; then
    help
    exit 1
fi

# Read Parameters
while [[ $# -gt 0 ]]; do
    key=$1

    case $key in
        --help) help
            exit 0
            ;;
        --debug) dry_run="echo"
            shift
            ;;
        --verbose) verbose="-verbose"
            shift
            ;;
        -i|--input) input="$2"
            shift
            shift
            ;;
        -d|--output_dir) output_dir="${2%%/*}"
            shift
            shift
            ;;
        -f|--output_filename) output_filename="$2"
            shift
            shift
            ;;
        -w|--width) width="$2"
            shift
            shift
            ;;
        -h|--height) height="$2"
            shift
            shift
            ;;
        -r|--rows) row_count="$2"
            shift
            shift
            ;;
        -c|--columns) column_count="$2"
            shift
            shift
            ;;
        -H|--horizontal_offset) initial_horizontal_offset="$2"
            shift
            shift
            ;;
        -V|--vertical_offset) initial_vertical_offset="$2"
            shift
            shift
            ;;
        -C|--coordinates) coordinates="$2"
            shift
            shift
            ;;
        *) echo "$key - Invalid Option"
            help
            exit 1
            ;;
    esac
done

# Safety Checks

## Checking either if coordinates or its separate counterparts exist
if ! [[ $coordinates =~ $re_coord ]]; then
    if ! [[ "$width" =~ $ren ]] || ! [[ "$height" =~ $ren ]] || ! [[ "$initial_horizontal_offset" =~ $ren ]] || ! [[ "$initial_vertical_offset" =~ $ren ]]; then
        echo "Please define coordinates in the 'HEIGHTxWIDTH+HORIZONTAL_OFFSET+VERTICAL_OFFSET' format"
        echo "Or individual width, height, and its initial offsets"
        exit 1
    fi
else
    width=$(echo $coordinates | cut -d'x' -f1)
    height=$(echo $coordinates | cut -d'x' -f2 | cut -d'+' -f1)
    initial_horizontal_offset=$(echo $coordinates | cut -d'+' -f2)
    initial_vertical_offset=$(echo $coordinates | cut -d'+' -f3)
fi

## Check if row and column number as correctly declared
if ! [[ "$row_count" =~ $ren ]] || ! [[ "$column_count" =~ $ren ]]; then
    echo "Please define valid integers for Row/Column count"
    exit 1
fi

## Check if output dir is valid
if ! [[ -d "$output_dir" ]]; then
    echo "Please provide a valid output directory"
    exit 1
fi

## Assume default filename
if [[ -z "$output_filename" ]]; then
    output_filename="sliced"
fi

## Input file/directory 'intelligence'
## If a valid directory, recurse through each file in the dir
## If a valid file, run only for that file
if [[ -z "$input" ]]; then
    echo "Please provide a valid input file or directory"
    exit 1
elif [[ -d "$input" ]]; then
    while_input=$(ls $input/*)
elif [[ -f "$input" ]]; then
    while_input=$input
else
    echo "$input is not a valid file or directory"
    exit 1
fi

# Debug info
if ! [[ -z $dry_run ]]; then
    echo
    echo "coordinates = $coordinates"
    echo "width = $width"
    echo "height = $height"
    echo "horizontal_offset = $initial_horizontal_offset"
    echo "vertical_offset = $initial_vertical_offset"
    echo "row count = $row_count"
    echo "column count = $column_count"
    echo "input = $input"
    echo "output_dir = $output_dir"
    echo "output_filename = $output_filename"
    echo
fi

# Program start
while read file; do
    if ! file "$file" | egrep -q 'image|bitmap'; then
        echo "$file is not a valid image. Aborting"
        exit 1
    fi

    file_ext=${file##*.}

    for column in $(seq 1 $column_count); do
        for row in $(seq 1 $row_count); do
            let "horizontal_offset=$initial_horizontal_offset+$width*($row-1)"
            let "vertical_offset=$initial_vertical_offset+$height*($column-1)"
            output="$output_dir/$output_filename-$(printf %02d $counter).$file_ext"

            echo "Slicing $file into $output"
            $dry_run convert $verbose "$file" -crop "${width}x${height}+${horizontal_offset}+${vertical_offset}" $output

            let "counter=$counter+1"
        done
    done
done < <(echo "$while_input")

Usage examples:

Using coordinates, single input file output filename (verbosity enabled)
./pnp_slicer.sh --verbose -C "750x1050+150+75" -i pages/abilities-0.png -d sliced_images -f abilities -c 3 -r 3

Using separate coordinates, directory input and omitting output filename (will assume 'sliced')
./pnp_slicer.sh -w 750 -h 1050 -H 150 -V 75 -i pages -d sliced_images -c 3 -r 3