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https://github.com/Hopiu/django-imagekit.git
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358bb1f6b0
This corrects the border removal, however, I'm not certain whether the interpretation of "tolerance" gels with expectations.
71 lines
2.5 KiB
Python
71 lines
2.5 KiB
Python
from ..lib import Image, ImageChops, ImageDraw, ImageStat
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class Side(object):
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TOP = 't'
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RIGHT = 'r'
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BOTTOM = 'b'
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LEFT = 'l'
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ALL = (TOP, RIGHT, BOTTOM, LEFT)
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def crop(img, bbox, sides=Side.ALL):
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bbox = (
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bbox[0] if Side.LEFT in sides else 0,
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bbox[1] if Side.TOP in sides else 0,
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bbox[2] if Side.RIGHT in sides else img.size[0],
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bbox[3] if Side.BOTTOM in sides else img.size[1],
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)
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return img.crop(bbox)
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def detect_border_color(img):
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mask = Image.new('1', img.size, 1)
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w, h = img.size[0] - 2, img.size[1] - 2
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if w > 0 and h > 0:
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draw = ImageDraw.Draw(mask)
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draw.rectangle([1, 1, w, h], 0)
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return ImageStat.Stat(img.convert('RGBA').histogram(mask)).median
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class TrimBorderColor(object):
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"""Trims a color from the sides of an image.
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"""
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def __init__(self, color=None, tolerance=0.3, sides=Side.ALL):
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"""
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:param color: The color to trim from the image, in a 4-tuple RGBA value,
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where each component is an integer between 0 and 255, inclusive. If
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no color is provided, the processor will attempt to detect the
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border color automatically.
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:param tolerance: A number between 0 and 1 where 0. Zero is the least
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tolerant and one is the most.
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:param sides: A list of sides that should be trimmed. Possible values
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are provided by the :class:`Side` enum class.
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"""
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self.color = color
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self.sides = sides
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self.tolerance = tolerance
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def process(self, img):
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source = img.convert('RGBA')
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border_color = self.color or tuple(detect_border_color(source))
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bg = Image.new('RGBA', img.size, border_color)
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diff = ImageChops.difference(source, bg)
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if self.tolerance not in (0, 1):
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# If tolerance is zero, we've already done the job. A tolerance of
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# one would mean to trim EVERY color, and since that would result
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# in a zero-sized image, we just ignore it.
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if not 0 <= self.tolerance <= 1:
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raise ValueError('%s is an invalid tolerance. Acceptable values'
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' are between 0 and 1 (inclusive).' % self.tolerance)
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tmp = ImageChops.constant(diff, int(self.tolerance * 255)) \
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.convert('RGBA')
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diff = ImageChops.subtract(diff, tmp)
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bbox = diff.getbbox()
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if bbox:
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img = crop(img, bbox, self.sides)
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return img
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