Python --Reduce photos beautifully with antialiasing

Applying anti-aliasing will reduce the jerkyness when reducing the photo. This is a Python code that reduces the photo files in a folder at once while maintaining the aspect ratio (aspect ratio), applies antialiasing, and saves them.

Comparison with / without anti-alias

I reduced the photos of about 4000px to 300px and compared them. In the bird image with AA, the small sand on the ground is hard to see because the color is integrated with the ground.

Installation

#Install PIL
pip install PIL --allow-external PIL --allow-unverified PIL

Enlargement and reduction code

Confirmed to work only in python2.7 environment of mac

resize.py

# -*- coding: utf-8 -*-
import commands
import Image
import re

#Image height pixels when shrinking
PHOTO_HEIGHT = 300

#Full path of the folder containing the image
BASE_DIR = "/Users/XXXXX/Desktop/Photos"

#Image regular expression name
PHOTO_REGEX = r"P.*.[jpg|JPG]"

#Image prefix after resizing
PHOTO_RESIZE_PREFIX = "r_"


def main():
    #Get full image path
    _cmd = "cd {} && ls".format(BASE_DIR)
    l = commands.getoutput(_cmd)
    l = l.split("\n")
    l = [_l for _l in l if re.match(PHOTO_REGEX, _l)]

    #Generate a folder for output
    commands.getoutput("mkdir {}/output".format(BASE_DIR))

    #Read an existing file in read mode
    for _l in l:
        before_path = '{}/{}'.format(BASE_DIR, _l)
        filename = '{}{}'.format(PHOTO_RESIZE_PREFIX, _l)
        after_path = '{}/output/{}'.format(BASE_DIR, filename)
        resize(before_path, after_path, filename=_l)  #Shrink


def resize(before, after, height=PHOTO_HEIGHT, filename="", aa_enable=True):
    """
Resize the image
    :param str before:Original image file path
    :param str after:Image file path after resizing
    :param int height:Image height after resizing
    :param bool aa_enable:Whether to enable antialiasing
    :return:
    """
    #Open image readonly
    img = Image.open(before, 'r')
    #Calculate image pixels after resizing
    before_x, before_y = img.size[0], img.size[1]
    x = int(round(float(height / float(before_y) * float(before_x))))
    y = height
    resize_img = img
    if aa_enable:
        #Shrink with antialiasing
        resize_img.thumbnail((x, y), Image.ANTIALIAS)
    else:
        #Shrink without antialiasing
        resize_img = resize_img.resize((x, y))

    #Save the resized image
    resize_img.save(after, 'jpeg', quality=100)
    print "RESIZED!:{}[{}x{}] --> {}x{}".format(filename, before_x, before_y, x, y)

#Run
main()

Execution result

>>> python resize.py
RESIZED!:P1040673.jpg[4592x3448] --> 400x300
RESIZED!:P1050388.JPG[4592x3448] --> 400x300
RESIZED!:P1050389.JPG[4592x3448] --> 400x300
RESIZED!:P1050390.JPG[4592x3448] --> 400x300
RESIZED!:P1050391.JPG[4592x3448] --> 400x300
RESIZED!:P1050392.JPG[4592x3448] --> 400x300
RESIZED!:P1050393.JPG[4592x3448] --> 400x300
RESIZED!:P1050394.JPG[4592x3448] --> 400x300