Python script to split an image into vertical slices. Useful for processing background images (i.e. cocos2d, etc.)

vslice.py

#!/usr/bin/env python
#
# Slice an image into the specified number of vertical slices.
#
# Usage: vslice.py [options] image output-path num-slices
# Use --help for a list of options.
#
# Andy Duplain <trojanfoe@gmail.com> 26-Feb-2014
#

import sys, os
from optparse import OptionParser
from PIL import Image

progName = None

def vslice(inputName, outputPath, baseName, numSlices, options):

    if options.zeroFill:
        outputFileFormat = "{0}-{1:03d}.png"
    else:
        outputFileFormat = "{0}-{1}.png"        

    image = Image.open(inputName)
    width, height = image.size
    sliceWidth = width / numSlices

    print "{0}: Image size={1}x{2}, slice width={3}".format(progName, width, height, sliceWidth)
    if sliceWidth * numSlices != width:
        print "{0}: Number of slices does not fit exactly ({1} != {2})".format(progName, sliceWidth * numSlices, width)

    for i in range(0, numSlices):
        # Box is (left, upper, right, bottom) and NOT (x, y, width, height)...
        x = sliceWidth * i
        box = (x, 0, x + sliceWidth, height)
        slice = image.crop(box)
        slice.load()

        if options.cropOutput:
            outputImage = Image.new(image.mode, (sliceWidth, height))
            outputImage.paste(slice, (0, 0, sliceWidth, height))
        else:
            outputImage = Image.new(image.mode, (width, height))
            outputImage.paste(slice, box)

        outputName = os.path.join(outputPath, outputFileFormat.format(baseName, i + 1))
        outputImage.save(outputName, "PNG")
        print "{0}: Saved slice {1} to {2}".format(progName, i + 1, outputName)

    return True

def main():
    global progName
    progName = os.path.basename(sys.argv[0])
    parser = OptionParser("usage: %prog [options] image output-path num-slices")
    parser.add_option("-c", "--crop-output", dest="cropOutput", action="store_true", default=False, help="Crop output image to slice")
    parser.add_option("-z", "--zero-fill", dest="zeroFill", action="store_true", default=False, help="Zero-fill numbered output filenames")
    (options, args) = parser.parse_args()
    if len(args) != 3:
        parser.error("Incorrect number of arguments")

    inputName = args[0]
    outputPath = args[1]
    numSlices = int(args[2])

    if numSlices < 2:
        parser.error("Incorrect number of slices")

    if not os.path.exists(outputPath):
        os.mkdir(outputPath)

    baseName = os.path.splitext(inputName)[0]

    vslice(inputName, outputPath, baseName, numSlices, options)

    print "{0}: Done.".format(progName)
    return 0

if __name__ == "__main__":
    sys.exit(main())