image_convert.py

#!/usr/bin/env python
'''
image_convert.py
~~~~~~~~~~~~~~~~~

A small tool to resize/compress/rotate image.

:copyright: Copyright (C) 2012 Yue Du <lyxint@gmail.com>
:license: BSD 2-Clause License
'''
import sys
import os
import optparse
from math import ceil
import Image, ExifTags

parser = optparse.OptionParser('python {0} [OPTION]... INPUTFILE [OUTPUTFILE]' .format(sys.argv[0]))
parser.add_option('--maxwidth', dest='maxwidth', default=None, help='max width')
parser.add_option('--maxheight', dest='maxheight', default=None, help='max height')
parser.add_option('--quality', dest='quality', default=None, help='quality')
parser.add_option('--rotate', dest='rotate', default=0, help='rotate')
parser.add_option('--format', dest='format', default=None, help='format')

options, args = parser.parse_args()
if len(args) == 0:
    parser.print_help()
    parser.exit(-1, '\nerror: No files\n')

inputfile = args[0]
outputfile = args[1] if len(args) >= 2 else inputfile
options.quality = int(options.quality) if options.quality else 100

im = Image.open(inputfile)
if inputfile == outputfile:
    options.format = options.format or im.format
else:
    ext = outputfile.rsplit('.')[-1].upper()
    if ext == 'JPG':
        ext = 'JPEG'
    if ext not in Image.SAVE:
        ext = im.format
    options.format = options.format or ext

# auto rotate/flip images which have Orientation.  
if hasattr(im, '_getexif') and im._getexif():
    tags = ExifTags.TAGS
    exif = dict((tags[k], v) for k, v in im._getexif().items() if k in tags)
    orientation = exif.get('Orientation', 1)
    if orientation == 1:
        pass
    elif orientation == 2:
        im = im.transpose(Image.FLIP_LEFT_RIGHT)
    elif orientation == 3:
        im = im.rotate(180, Image.BICUBIC, expand=True)
    elif orientation == 4:
        im = im.rotate(180, Image.BICUBIC, expand=True)
        im = im.transpose(Image.FLIP_LEFT_RIGHT)
    elif orientation == 5:
        im = im.rotate(270, Image.BICUBIC, expand=True)
        im = im.transpose(Image.FLIP_LEFT_RIGHT)
    elif orientation == 6:
        im = im.rotate(270, Image.BICUBIC, expand=True)
    elif orientation == 7:
        im = im.rotate(90, Image.BICUBIC, expand=True)
        im = im.transpose(Image.FLIP_LEFT_RIGHT)
    elif orientation == 8:
        im = im.rotate(90, Image.BICUBIC, expand=True)

if im.mode != 'RGBA':
    im = im.convert('RGBA')

if options.rotate:
    rotate = int(options.rotate)
    im = im.rotate(rotate, Image.BICUBIC, expand=True)

if options.maxwidth:
    maxwidth = int(options.maxwidth)
    if im.size[0] > maxwidth:
        ratio = maxwidth * 1.0 / im.size[0]
        size = map(lambda x: int(x*ratio), im.size)
        im = im.resize(size, Image.ANTIALIAS)

if options.maxheight:
    maxheight = int(options.maxheight)
    if im.size[1] > maxheight:
        ratio = maxheight * 1.0 / im.size[1]
        size = map(lambda x: int(x*ratio), im.size)
        im = im.resize(size, Image.ANTIALIAS)

with open(outputfile, 'wb') as f:
    im.save(f, options.format, quality=options.quality)

PIL 又慢又会丢 EXIF……

确实会丢EXIF, 有方法可以保持EXIF但是要装第三方库....