After reading about OptiPNG, I decided to add it into the mix of flatten.py. Since it doesn't support reducing bit depths of grayscale images, I have the script run pngcrush first and then OptiPNG.
Since the last post about flatten, I've made a few other changes as well, such as passing -bit_depth to pngcrush when a bit depth is provided. Since I use this script to compress images for my webcomic, that's an important change.
flatten.py
#!/usr/bin/python
from sys import argv, stderr, exit
from subprocess import Popen
from optparse import OptionParser, OptionValueError
from copy import copy
from os import remove
from os import close as os_close
from re import compile as re_compile
from os.path import join, isfile
from tempfile import mkstemp
size = re_compile('^(.+)x(.+)$')
def check_size(option, opt_str, value, parser):
m = size.search(value)
if m:
parser.values.size = m.group(1), m.group(2)
else:
raise OptionValueError('Invalid size: %s' % value)
filext = re_compile('^(.+)\.(.+)$')
filext_png = re_compile('\.png$')
img_type = ['Bilevel', 'Grayscale', 'GrayscaleMatte', 'Palette', 'PaletteMatte', 'TrueColor', 'TrueColorMatte', 'ColorSeparate', 'ColorSeparationMatte', 'Optimize']
img_cspace = ['CMY', 'CMYK', 'Gray', 'HSB', 'HSL', 'HWB', 'Lab', 'Log', 'OHTA', 'Rec601Luma', 'Rec601YCbCr', 'Rec709Luma', 'Rec709YCbCr', 'RGB', 'sRGB', 'Transparent', 'XYZ', 'YCbCr', 'YCC', 'YIQ', 'YPbPr', 'YUV']
pngcrush = ['pngcrush', '-rem', 'gAMA', '-rem', 'cHRM', '-rem', 'iCCP', '-rem', 'sRGB']
parser = OptionParser(usage = 'Usage: %prog [ options ] input [ output ]')
parser.add_option('-s', '--size', dest = 'size', type = 'string', action = 'callback', callback = check_size, default = None, help = 'The output size: WIDTHxHEIGHT')
parser.add_option('-n', '--no-clobber', dest = 'clobber', default = True, action = 'store_false', help = 'The output size: WIDTHxHEIGHT')
parser.add_option('-f', '--filter', dest = 'filter', default = 'Catrom', help = 'The filter to resize with if necessary.')
parser.add_option('-b', '--background', dest = 'background', default = 'white', help = 'The background when flattening.')
parser.add_option('-F', '--no-flatten', dest = 'flatten', default = True, action = 'store_false', help = 'Don\'t flatten the output.')
parser.add_option('-t', '--type', dest = 'type', type = 'string', default = None, help = 'The type of the output image: analogous to both -type and -colorspace in ImageMagick')
parser.add_option('-d', '--depth', dest = 'depth', type = 'int', default = None, help = 'The depth of the output image.')
options, args = parser.parse_args()
if len(args):
input = args.pop(0)
if isfile(input):
output = None
pngout = False
if len(args):
output = args.pop(0)
if filext_png.search(output):
pngout = True
else:
m = filext.search(input)
if not m is None:
output = '%s_small.%s' % (m.group(1), m.group(2))
if m.group(2) == 'png':
pngout = True
else:
output = '%s_small.png' % input
pngout = True
if not options.clobber and isfile(output):
print >>stderr, 'Output file exists:', output
exit(2)
# ACTUAL PROCESSING
args = ['convert', input]
if not options.type is None:
if options.type in img_type:
args += ['-type', options.type]
if not options.depth is None:
args += ['-depth', str(options.depth)]
elif options.type in img_cspace:
args += ['-colorspace', options.type]
if not options.depth is None:
args += ['-depth', str(options.depth)]
if options.flatten:
args += ['-background', options.background, '-flatten', '+matte']
if not options.size is None:
args += ['-filter', options.filter, '-resize', '%sx%s' % options.size]
if pngout:
# Run convert
fd, tmpfile = mkstemp()
os_close(fd)
args.append('png:' + tmpfile)
Popen(args).communicate()
# Run pngcrush
args = copy(pngcrush)
if not options.depth is None:
args += ['-bit_depth', str(options.depth)]
args += [tmpfile, output]
Popen(args).communicate()
remove(tmpfile)
# Run optipng
Popen(['optipng', '-o9', output]).communicate()
else:
args.append(output)
Popen(args).communicate()
# END
else:
print >>stderr, 'No such file:', input
exit(2)
else:
parser.print_help()
exit(1)The runtime options are the same as flatten.py.
