56 lines
1.7 KiB
Python
56 lines
1.7 KiB
Python
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""" Function for applying watermarks to images.
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Original found here:
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http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/362879
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"""
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try:
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import Image
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import ImageEnhance
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except ImportError:
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try:
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from PIL import Image, ImageEnhance
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except ImportError:
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raise ImportError("The Python Imaging Library was not found.")
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def reduce_opacity(im, opacity):
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"""Returns an image with reduced opacity."""
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assert opacity >= 0 and opacity <= 1
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if im.mode != 'RGBA':
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im = im.convert('RGBA')
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else:
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im = im.copy()
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alpha = im.split()[3]
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alpha = ImageEnhance.Brightness(alpha).enhance(opacity)
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im.putalpha(alpha)
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return im
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def apply_watermark(im, mark, position, opacity=1):
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"""Adds a watermark to an image."""
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if opacity < 1:
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mark = reduce_opacity(mark, opacity)
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if im.mode != 'RGBA':
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im = im.convert('RGBA')
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# create a transparent layer the size of the image and draw the
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# watermark in that layer.
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layer = Image.new('RGBA', im.size, (0, 0, 0, 0))
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if position == 'tile':
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for y in range(0, im.size[1], mark.size[1]):
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for x in range(0, im.size[0], mark.size[0]):
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layer.paste(mark, (x, y))
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elif position == 'scale':
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# scale, but preserve the aspect ratio
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ratio = min(
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float(im.size[0]) / mark.size[0], float(im.size[1]) / mark.size[1])
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w = int(mark.size[0] * ratio)
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h = int(mark.size[1] * ratio)
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mark = mark.resize((w, h))
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layer.paste(mark, (int((im.size[0] - w) / 2), int((im.size[1] - h) / 2)))
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else:
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layer.paste(mark, position)
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# composite the watermark with the layer
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return Image.composite(layer, im, layer)
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