Mercurial > public > madeira
comparison photologue/utils/watermark.py @ 71:e2868ad47a1e
For Django 1.4, using the new manage.py.
| author | Brian Neal <bgneal@gmail.com> |
|---|---|
| date | Sat, 14 Apr 2012 16:40:29 -0500 |
| parents | madeira/photologue/utils/watermark.py@63e4211628e1 |
| children |
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| 70:f26cdda0ad8b | 71:e2868ad47a1e |
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| 1 """ Function for applying watermarks to images. | |
| 2 | |
| 3 Original found here: | |
| 4 http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/362879 | |
| 5 | |
| 6 """ | |
| 7 | |
| 8 try: | |
| 9 import Image | |
| 10 import ImageEnhance | |
| 11 except ImportError: | |
| 12 try: | |
| 13 from PIL import Image | |
| 14 from PIL import ImageEnhance | |
| 15 except ImportError: | |
| 16 raise ImportError("The Python Imaging Library was not found.") | |
| 17 | |
| 18 def reduce_opacity(im, opacity): | |
| 19 """Returns an image with reduced opacity.""" | |
| 20 assert opacity >= 0 and opacity <= 1 | |
| 21 if im.mode != 'RGBA': | |
| 22 im = im.convert('RGBA') | |
| 23 else: | |
| 24 im = im.copy() | |
| 25 alpha = im.split()[3] | |
| 26 alpha = ImageEnhance.Brightness(alpha).enhance(opacity) | |
| 27 im.putalpha(alpha) | |
| 28 return im | |
| 29 | |
| 30 def apply_watermark(im, mark, position, opacity=1): | |
| 31 """Adds a watermark to an image.""" | |
| 32 if opacity < 1: | |
| 33 mark = reduce_opacity(mark, opacity) | |
| 34 if im.mode != 'RGBA': | |
| 35 im = im.convert('RGBA') | |
| 36 # create a transparent layer the size of the image and draw the | |
| 37 # watermark in that layer. | |
| 38 layer = Image.new('RGBA', im.size, (0,0,0,0)) | |
| 39 if position == 'tile': | |
| 40 for y in range(0, im.size[1], mark.size[1]): | |
| 41 for x in range(0, im.size[0], mark.size[0]): | |
| 42 layer.paste(mark, (x, y)) | |
| 43 elif position == 'scale': | |
| 44 # scale, but preserve the aspect ratio | |
| 45 ratio = min( | |
| 46 float(im.size[0]) / mark.size[0], float(im.size[1]) / mark.size[1]) | |
| 47 w = int(mark.size[0] * ratio) | |
| 48 h = int(mark.size[1] * ratio) | |
| 49 mark = mark.resize((w, h)) | |
| 50 layer.paste(mark, ((im.size[0] - w) / 2, (im.size[1] - h) / 2)) | |
| 51 else: | |
| 52 layer.paste(mark, position) | |
| 53 # composite the watermark with the layer | |
| 54 return Image.composite(layer, im, layer) | |
| 55 | |
| 56 def test(): | |
| 57 im = Image.open('test.png') | |
| 58 mark = Image.open('overlay.png') | |
| 59 watermark(im, mark, 'tile', 0.5).show() | |
| 60 watermark(im, mark, 'scale', 1.0).show() | |
| 61 watermark(im, mark, (100, 100), 0.5).show() | |
| 62 | |
| 63 if __name__ == '__main__': | |
| 64 test() |