45 lines
1.1 KiB
Python
45 lines
1.1 KiB
Python
from PIL import Image, ImageDraw
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LIMIT = 0xffff
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def draw_wu_line(draw, x, y, w, h):
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# Without loss of generality only lines in the first oc
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assert(w > 0 and h > 0 and w > h)
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k = LIMIT * (h-1) // w
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x1 = x + w - 1
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y1 = y + h - 1
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d = 0
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while x1 > x:
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draw.point([(x, y), (x1, y1)], fill=(0, 0, 0, 0xff - (d >> 8)))
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draw.point([(x, y + 1), (x1, y1 - 1)], fill=(0, 0, 0, d >> 8))
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x += 1
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x1 -= 1
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if d + k >= LIMIT:
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d = k - (LIMIT - d)
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y += 1
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y1 -= 1
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else:
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d += k
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if x1 == x:
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if y1 == y:
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points = [(x, y)]
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alpha = 0xff
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else:
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points = [(x, y), (x, y1)]
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alpha = 0x7f
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draw.point(points, fill=(0, 0, 0, alpha))
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size = 100, 33
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im = Image.new('RGBA', size)
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d = ImageDraw.Draw(im, 'RGBA')
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draw_wu_line(d, 0, 0, *size)
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##for w in range(51, 100):
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## draw_wu_line(d, 0, 0, w, 50)
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base = Image.new('RGBA', size, (0xff, 0xff, 0xff, 0xff))
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base.alpha_composite(im)
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base.save('wu_demo.png')
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