Python Image Resizer using Python Wand and ImageMagick (inspired by flickr style resize)

ImagickHelper.py

#!/usr/bin/env python

from wand.image import Image


#create class for get exif data from image
class ExifData:
	key_exif = ['date:create',
				'date:modify',
				'exif:ApertureValue',
				'exif:BrightnessValue',
				'exif:ColorSpace',
				'exif:ComponentsConfiguration',
				'exif:Compression',
				'exif:DateTime',
				'exif:DateTimeDigitized',
				'exif:DateTimeOriginal',
				'exif:ExifImageLength',
				'exif:ExifImageWidth',
				'exif:ExifOffset',
				'exif:ExifVersion',
				'exif:ExposureMode',
				'exif:ExposureProgram',
				'exif:ExposureTime',
				'exif:Flash',
				'exif:FlashPixVersion',
				'exif:FNumber',
				'exif:FocalLength',
				'exif:FocalLengthIn35mmFilm',
				'exif:ISOSpeedRatings',
				'exif:JPEGInterchangeFormat',
				'exif:JPEGInterchangeFormatLength',
				'exif:Make',
				'exif:MeteringMode',
				'exif:Model',
				'exif:Orientation',
				'exif:ResolutionUnit',
				'exif:SceneCaptureType',
				'exif:SceneType',
				'exif:SensingMethod',
				'exif:ShutterSpeedValue',
				'exif:Software',
				'exif:SubjectArea',
				'exif:SubSecTimeDigitized',
				'exif:SubSecTimeOriginal',
				'exif:WhiteBalance',
				'exif:XResolution',
				'exif:YCbCrPositioning',
				'exif:YResolution',
				'jpeg:colorspace',
				'jpeg:sampling-factor']

	exif_orientation_column = [{"top":[6, 5]}, {"bottom":[7, 8]}, {"left":[1, 4]}, {"right":[2, 3]}]
	exif_orientation_row = [{"top":[1, 3]}, {"bottom":[3, 4]}, {"left":[5, 8]}, {"right":[6, 7]}]

	exif_data = {}

	def __init__(self):
		return None

	def get_exif_data(self, img_path):
		#read image
		img = Image(filename=img_path)
		img_exif = img.metadata
		for key in self.key_exif:
			self.exif_data[key] = img_exif[key]

		return self.exif_data

	def check_orientation(self, img):
		exif = img.metadata
		#print exif['exif:Orientation']
		return exif['exif:Orientation']

class ImageResizer:

	#predefine image size
	#square size
	square_150x150 = '150x150^'
	square_320x320 = '320x320^'
	square_500x500 = '500x500^'
	square_640x640 = '640x640^'

	square_150x150_size = [150, 150]
	square_320x320_size = [320, 320]
	square_500x500_size = [500, 500]
	square_640x640_size = [640, 640]

	square_150x150_name = 'square_150x150'
	square_320x320_name = 'square_320x320'
	square_500x500_name = 'square_500x500'
	square_640x640_name = 'square_640x640'

	#non_square_size
	small_240x180 = '240x180^'
	small_320x240 = '320x240^'
	medium_640x480 = '640x480^'
	medium_800x600 = '800x600^'
	large_1024x768 = '1024x768^'
	large_1600x1200	= '1600x1200^'

	small_240x180_size = [240, 180]
	small_320x240_size = [320, 240]
	medium_640x480_size = [640, 480]
	medium_800x600_size = [800, 600]
	large_1024x768_size = [1024, 768]
	large_1600x1200_size = [1600, 1200]

	small_240x180_name = 'small_240x180'
	small_320x240_name = 'small_320x240'
	medium_640x480_name = 'medium_640x480'
	medium_800x600_name = 'medium_800x600'
	large_1024x768_name = 'large_1024x768'
	large_1600x1200_name = 'large_1600x1200'

	def __init__(self):
		return None

	def generate_square_img(self, img_path, size_config, size_img, size_name, dest_path):
		#open_image
		img = Image(filename=img_path)
		#transform with resize scale config
		img.transform(resize=size_config)
		#try to crop, calculate width crop first
		target_size = size_img[1] #use one because its square
		width, height = img.size
		#print "width, height ", width, height
		crop_start, crop_end = [0, 0] #add new size params
		#calculate
		crop_start = (width - target_size) / 2
		crop_end = crop_start + target_size
		
		#print crop_start, crop_end, target_size, (crop_end - crop_start)
		'''
		exProcessor = ExifData()
		#rotate image if necessary
		if exProcessor.check_orientation(img) in [6, 7]:
			img.rotate(90)
			img.metadata['exif:Orientation'] = 1
		if exProcessor.check_orientation(img) in [6, 8]:
			img.rotate(-90)
			img.metadata['exif:Orientation'] = 1
		if exProcessor.check_orientation(img) in [3, 4]:
			img.rotate(180) 
			img.metadata['exif:Orientation'] = 1
		'''

		#do cropping
		with img[crop_start:crop_end, :] as square_image:
			#save 
			square_image.save(filename=''.join([dest_path, size_name, '.jpg']))

	def resize_image(self, img_path, size_config, size_name, dest_path):
		#open image
		img = Image(filename=img_path)
		#transform using resize config
		img.transform(resize=size_config)
		'''
		exProcessor = ExifData()
		#rotate image if necessary
		if exProcessor.check_orientation(img) in [6, 7]:
			img.rotate(90)
			img.metadata['exif:Orientation'] = 1
		if exProcessor.check_orientation(img) in [6, 8]:
			img.rotate(-90)
			img.metadata['exif:Orientation'] = 1
		if exProcessor.check_orientation(img) in [3, 4]:
			img.rotate(180) 
			img.metadata['exif:Orientation'] = 1
		'''
		#save img
		img.save(filename=''.join([dest_path, size_name, '.jpg']))

	def generate_all_image(self, image_path, dest_path):
		#generate square image
		self.generate_square_img(image_path, self.square_150x150, self.square_150x150_size, self.square_150x150_name, dest_path)
		self.generate_square_img(image_path, self.square_320x320, self.square_320x320_size, self.square_320x320_name, dest_path)
		self.generate_square_img(image_path, self.square_500x500, self.square_500x500_size, self.square_500x500_name, dest_path)
		self.generate_square_img(image_path, self.square_640x640, self.square_640x640_size, self.square_640x640_name, dest_path)

		#generate non square image
		self.resize_image(image_path, self.small_240x180, self.small_240x180_name, dest_path)
		self.resize_image(image_path, self.small_320x240, self.small_320x240_name, dest_path)
		self.resize_image(image_path, self.medium_640x480, self.medium_640x480_name, dest_path)
		self.resize_image(image_path, self.medium_800x600, self.medium_800x600_name, dest_path)
		self.resize_image(image_path, self.large_1024x768, self.large_1024x768_name, dest_path)
		self.resize_image(image_path, self.large_1600x1200, self.large_1600x1200_name, dest_path)

		return None