138 lines
4.5 KiB
Python
138 lines
4.5 KiB
Python
#!/usr/bin/env python3
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"""
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ffgeom.py
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Copyright (C) 2005 Aaron Cyril Spike, aaron@ekips.org
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This file is part of FretFind 2-D.
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FretFind 2-D is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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FretFind 2-D is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with FretFind 2-D; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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"""
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import math
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try:
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NaN = float('NaN')
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except ValueError:
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PosInf = 1e300000
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NaN = PosInf/PosInf
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class Point:
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precision = 5
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def __init__(self, x, y):
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self.__coordinates = {'x' : float(x), 'y' : float(y)}
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def __getitem__(self, key):
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return self.__coordinates[key]
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def __setitem__(self, key, value):
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self.__coordinates[key] = float(value)
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def __repr__(self):
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return '(%s, %s)' % (round(self['x'],self.precision),round(self['y'],self.precision))
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def copy(self):
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return Point(self['x'],self['y'])
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def translate(self, x, y):
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self['x'] += x
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self['y'] += y
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def move(self, x, y):
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self['x'] = float(x)
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self['y'] = float(y)
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class Segment:
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def __init__(self, e0, e1):
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self.__endpoints = [e0, e1]
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def __getitem__(self, key):
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return self.__endpoints[key]
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def __setitem__(self, key, value):
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self.__endpoints[key] = value
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def __repr__(self):
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return repr(self.__endpoints)
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def copy(self):
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return Segment(self[0],self[1])
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def translate(self, x, y):
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self[0].translate(x,y)
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self[1].translate(x,y)
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def move(self,e0,e1):
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self[0] = e0
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self[1] = e1
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def delta_x(self):
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return self[1]['x'] - self[0]['x']
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def delta_y(self):
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return self[1]['y'] - self[0]['y']
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#alias functions
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run = delta_x
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rise = delta_y
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def slope(self):
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if self.delta_x() != 0:
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return self.delta_x() / self.delta_y()
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return NaN
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def intercept(self):
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if self.delta_x() != 0:
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return self[1]['y'] - (self[0]['x'] * self.slope())
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return NaN
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def distanceToPoint(self, p):
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s2 = Segment(self[0],p)
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c1 = dot(s2,self)
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if c1 <= 0:
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return Segment(p,self[0]).length()
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c2 = dot(self,self)
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if c2 <= c1:
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return Segment(p,self[1]).length()
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return self.perpDistanceToPoint(p)
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def perpDistanceToPoint(self, p):
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len = self.length()
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if len == 0: return NaN
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return math.fabs(((self[1]['x'] - self[0]['x']) * (self[0]['y'] - p['y'])) - \
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((self[0]['x'] - p['x']) * (self[1]['y'] - self[0]['y']))) / len
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def angle(self):
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return math.pi * (math.atan2(self.delta_y(), self.delta_x())) / 180
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def length(self):
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return math.sqrt((self.delta_x() ** 2) + (self.delta_y() ** 2))
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def pointAtLength(self, len):
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if self.length() == 0: return Point(NaN, NaN)
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ratio = len / self.length()
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x = self[0]['x'] + (ratio * self.delta_x())
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y = self[0]['y'] + (ratio * self.delta_y())
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return Point(x, y)
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def pointAtRatio(self, ratio):
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if self.length() == 0: return Point(NaN, NaN)
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x = self[0]['x'] + (ratio * self.delta_x())
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y = self[0]['y'] + (ratio * self.delta_y())
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return Point(x, y)
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def createParallel(self, p):
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return Segment(Point(p['x'] + self.delta_x(), p['y'] + self.delta_y()), p)
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def intersect(self, s):
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return intersectSegments(self, s)
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def intersectSegments(s1, s2):
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x1 = s1[0]['x']
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x2 = s1[1]['x']
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x3 = s2[0]['x']
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x4 = s2[1]['x']
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y1 = s1[0]['y']
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y2 = s1[1]['y']
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y3 = s2[0]['y']
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y4 = s2[1]['y']
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denom = ((y4 - y3) * (x2 - x1)) - ((x4 - x3) * (y2 - y1))
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num1 = ((x4 - x3) * (y1 - y3)) - ((y4 - y3) * (x1 - x3))
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num2 = ((x2 - x1) * (y1 - y3)) - ((y2 - y1) * (x1 - x3))
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num = num1
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if denom != 0:
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x = x1 + ((num / denom) * (x2 - x1))
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y = y1 + ((num / denom) * (y2 - y1))
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return Point(x, y)
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return Point(NaN, NaN)
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def dot(s1, s2):
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return s1.delta_x() * s2.delta_x() + s1.delta_y() * s2.delta_y() |