annotate core/image.py @ 628:c6292e46e617
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| author |
Brian Neal <bgneal@gmail.com> |
| date |
Mon, 12 Nov 2012 16:40:54 -0600 |
| parents |
ee87ea74d46b |
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234726f5a47a |
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line source |
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bgneal@265
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1 """
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2 This file contains common utility functions for manipulating images for
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3 the rest of the applications in the project.
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4 """
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5 from PIL import ImageFile
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6 from PIL import Image
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7
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8
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9 def parse_image(file):
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10 """
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11 Returns a PIL Image from the supplied Django file object.
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12 Throws IOError if the file does not parse as an image file or some other
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13 I/O error occurred.
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14
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15 """
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16 parser = ImageFile.Parser()
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17 for chunk in file.chunks():
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18 parser.feed(chunk)
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19 image = parser.close()
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20 return image
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21
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22
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23 def downscale_image_square(image, size):
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24 """
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25 Scale an image to the square dimensions given by size (in pixels).
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26 The new image is returned.
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27 If the image is already smaller than (size, size) then no scaling
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28 is performed and the image is returned unchanged.
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29
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30 """
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31 # don't upscale
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32 if (size, size) >= image.size:
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33 return image
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34
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35 (w, h) = image.size
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36 if w > h:
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37 diff = (w - h) / 2
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38 image = image.crop((diff, 0, w - diff, h))
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39 elif h > w:
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40 diff = (h - w) / 2
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41 image = image.crop((0, diff, w, h - diff))
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42 image = image.resize((size, size), Image.ANTIALIAS)
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43 return image
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