celutz/panorama/gen_tiles.py

# -*- coding: utf-8 -*-

"""
Given an image, generate a set of tiles at various zoom levels.
The format of the filename of times is:

  00<zoom>-00<x>-00<y>.jpg

where zoom is 0 for the original size, 1 when the image is downscaled 2
times, 2 when the image is downscaled 4 times, etc.
"""

from __future__ import unicode_literals, division, print_function

import sys
import os
import tempfile

import PIL.Image
from PIL import ImageDraw


def gen_tiles(image, output_path, min_scale=0, max_scale=8, crop_x=256, crop_y=256):
    orig_im = PIL.Image.open(image)
    for scale in range(min_scale, max_scale + 1):
        if scale == 0:
            im = orig_im
            scaled_size = im.size
        else:
            scaled_size = (orig_im.size[0] >> scale, orig_im.size[1] >> scale)
            im = orig_im.resize(scaled_size, resample=PIL.Image.BILINEAR)
        # Compute a size that is a multiple of the tile size
        rounded_size = (crop_x + crop_x * ((im.size[0] - 1) // crop_x),
                        crop_y + crop_y * ((im.size[1] - 1) // crop_y))
        if rounded_size != scaled_size:
            im = im.transform(rounded_size, PIL.Image.AFFINE, (1, 0, 0, 0, 1, 0))
            if False and rounded_size[0] != scaled_size[0]: # TODO: check if 360 or not
                # Repeat the same image horizontally
                print((scale, 0, 0, rounded_size[0] - scaled_size[0], scaled_size[1]))
                print((scale, scaled_size[0], 0, rounded_size[0], scaled_size[1]))
                cropped = im.crop((0, 0, rounded_size[0] - scaled_size[0], scaled_size[1]))
                im.paste(cropped, (scaled_size[0], 0, rounded_size[0], scaled_size[1]))
        for x in range(0, im.size[0], crop_x):
            for y in range(0, im.size[1], crop_y):
                geom = (x, y, min(im.size[0], x + crop_x), min(im.size[1], y + crop_y))
                dest = os.path.join(output_path,
                                    "{}-{}-{}.jpg".format(-scale,
                                                          x // crop_x,
                                                          y // crop_y))
                tile = im.crop(geom)
                #draw = ImageDraw.Draw(tile)
                #draw.line((0, 0, 0, 255), width=2, fill="red")
                #draw.line((0, 255, 255, 255), width=2, fill="red")
                #draw.line((255, 255, 255, 0), width=2, fill="red")
                #draw.line((255, 0, 0, 0), width=2, fill="red")
                tile.save(dest)


if __name__ == '__main__':
    if len(sys.argv) < 2:
        print("Usage: {} <image>".format(sys.argv[0]))
        print("Generate tiles of the given image.")
        exit(1)
    origin = sys.argv[1]
    out = tempfile.mkdtemp(prefix="demo-pano-")
    print("Generating tiles in {} ...".format(out))
    gen_tiles(origin, out)