Create a mosaic of tiles

tiler.py

from PIL import Image, ImageOps
import requests


class Tiler(object):

	def __init__(self, images, rows=4, tile_size=(135, 135)):
		self.images = images
		self.rows = rows
		self.tile_size = tile_size
		self.output = 'tiler/output.jpg'
		self.working_file_name = 'tiler/tiltiler-working-cache'
		self.working_file_name_thumb = 'tiler/tiler-working-cache-thumb-%s'

	def download_raw_image(self, image):
		"""Pull the raw image into a local cache"""

		try:
			r = requests.get(image)
			with open(self.working_file_name, 'wb') as f:
				for chunk in r.iter_content(50):
					f.write(chunk)
		except Exception, e:
			return False

		return True

	def build(self):
		"""Build the mosaic from the raw images"""

		downloaded_images = []

		# Loop over the images and build a set suitable for tiling
		for index, image in enumerate(self.images):
			# Get the image as a file
			fetched_raw = self.download_raw_image(image)

			fname_thumb = self.working_file_name_thumb % index

			if not fetched_raw:
				continue

			# Read in and create a thumbnail
			try:
				im = Image.open(self.working_file_name)
				thumb = ImageOps.fit(im, self.tile_size, Image.ANTIALIAS)
				thumb.save(fname_thumb, 'JPEG')
			except IOError:
				continue

			downloaded_images.append(fname_thumb)

		# Get the dimensions of the canvas
		items_per_row = (len(downloaded_images) / self.rows)
		width = self.tile_size[0] * items_per_row
		height = self.tile_size[1] * self.rows

		canvas = Image.new('RGB', (width, height), 'white')

		# Build the tiles on the canvas
		for index, image in enumerate(downloaded_images):
			# Open the thumb we created earlier
			im = Image.open(image)

			# Get the point
			top, left = 0, 0

			top = self.tile_size[1] * (index / items_per_row)

			if index % items_per_row:
				left = self.tile_size[0] * (index % items_per_row)

			# Paste the thumb on the canvas
			canvas.paste(im, (left, top))

		# Save out the canvas
		canvas.save(self.output, 'JPEG')