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annotate Resources/Computations/IntersectSegmentAndHorizontalLine.py @ 781:2bb72826fa3f

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IVolumeImage
author Sebastien Jodogne <s.jodogne@gmail.com>
date Mon, 27 May 2019 11:45:18 +0200
parents 35c2b85836ce
children
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1 #!/usr/bin/env python
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2
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3 from sympy import *
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4
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5 # Intersection between the 2D line segment (prevX,prevY)-(curX,curY) and the
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6 # horizontal line "y = y0" using homogeneous coordinates
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7
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8 prevX, prevY, curX, curY, y0 = symbols('prevX prevY curX curY y0')
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9
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10 p1 = Matrix([prevX, prevY, 1])
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11 p2 = Matrix([curX, curY, 1])
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12 l1 = p1.cross(p2)
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13
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14 h1 = Matrix([0, y0, 1])
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15 h2 = Matrix([1, y0, 1])
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16 l2 = h1.cross(h2)
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17
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18 a = l1.cross(l2)
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20 #pprint(cse(a/a[2], symbols = symbols('a b')))
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21 pprint(a / a[2])