oops, this one is actually used by other extensions too - restoring

diff --git a/share/extensions/ffgeom.py b/share/extensions/ffgeom.py
new file mode 100644 (file)
index 0000000..24d80a1
--- /dev/null
+++ b/share/extensions/ffgeom.py
@@ -0,0 +1,138 @@
+#!/usr/bin/env python
+"""
+    ffgeom.py
+    Copyright (C) 2005 Aaron Cyril Spike, aaron@ekips.org
+
+    This file is part of FretFind 2-D.
+
+    FretFind 2-D is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    FretFind 2-D is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with FretFind 2-D; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+"""
+import math
+try:
+    NaN = float('NaN')
+except ValueError:
+    PosInf = 1e300000
+    NaN = PosInf/PosInf
+
+class Point:
+    precision = 5
+    def __init__(self, x, y):
+        self.__coordinates = {'x' : float(x), 'y' : float(y)}
+    def __getitem__(self, key):
+        return self.__coordinates[key]
+    def __setitem__(self, key, value):
+        self.__coordinates[key] = float(value)
+    def __repr__(self):
+        return '(%s, %s)' % (round(self['x'],self.precision),round(self['y'],self.precision))
+    def copy(self):
+        return Point(self['x'],self['y'])
+    def translate(self, x, y):
+        self['x'] += x
+        self['y'] += y
+    def move(self, x, y):
+        self['x'] = float(x)
+        self['y'] = float(y)
+
+class Segment:
+    def __init__(self, e0, e1):
+        self.__endpoints = [e0, e1]
+    def __getitem__(self, key):
+        return self.__endpoints[key]
+    def __setitem__(self, key, value):
+        self.__endpoints[key] = value
+    def __repr__(self):
+        return repr(self.__endpoints)
+    def copy(self):
+        return Segment(self[0],self[1])
+    def translate(self, x, y):
+        self[0].translate(x,y)
+        self[1].translate(x,y)
+    def move(self,e0,e1):
+        self[0] = e0
+        self[1] = e1
+    def delta_x(self):
+        return self[1]['x'] - self[0]['x']
+    def delta_y(self):
+        return self[1]['y'] - self[0]['y']
+    #alias functions
+    run = delta_x
+    rise = delta_y
+    def slope(self):
+        if self.delta_x() != 0:
+            return self.delta_x() / self.delta_y()
+        return NaN
+    def intercept(self):
+        if self.delta_x() != 0:
+            return self[1]['y'] - (self[0]['x'] * self.slope())
+        return NaN
+    def distanceToPoint(self, p):
+        s2 = Segment(self[0],p)
+        c1 = dot(s2,self)
+        if c1 <= 0:
+            return Segment(p,self[0]).length()
+        c2 = dot(self,self)
+        if c2 <= c1:
+            return Segment(p,self[1]).length()
+        return self.perpDistanceToPoint(p)
+    def perpDistanceToPoint(self, p):
+        len = self.length()
+        if len == 0: return NaN
+        return math.fabs(((self[1]['x'] - self[0]['x']) * (self[0]['y'] - p['y'])) - \
+            ((self[0]['x'] - p['x']) * (self[1]['y'] - self[0]['y']))) / len
+    def angle(self):
+        return math.pi * (math.atan2(self.delta_y(), self.delta_x())) / 180
+    def length(self):
+        return math.sqrt((self.delta_x() ** 2) + (self.delta_y() ** 2))
+    def pointAtLength(self, len):
+        if self.length() == 0: return Point(NaN, NaN)
+        ratio = len / self.length()
+        x = self[0]['x'] + (ratio * self.delta_x())
+        y = self[0]['y'] + (ratio * self.delta_y())
+        return Point(x, y)
+    def pointAtRatio(self, ratio):
+        if self.length() == 0: return Point(NaN, NaN)
+        x = self[0]['x'] + (ratio * self.delta_x())
+        y = self[0]['y'] + (ratio * self.delta_y())
+        return Point(x, y)
+    def createParallel(self, p):
+        return Segment(Point(p['x'] + self.delta_x(), p['y'] + self.delta_y()), p)
+    def intersect(self, s):
+        return intersectSegments(self, s)
+
+def intersectSegments(s1, s2):
+    x1 = s1[0]['x']
+    x2 = s1[1]['x']
+    x3 = s2[0]['x']
+    x4 = s2[1]['x']
+    
+    y1 = s1[0]['y']
+    y2 = s1[1]['y']
+    y3 = s2[0]['y']
+    y4 = s2[1]['y']
+    
+    denom = ((y4 - y3) * (x2 - x1)) - ((x4 - x3) * (y2 - y1))
+    num1 = ((x4 - x3) * (y1 - y3)) - ((y4 - y3) * (x1 - x3))
+    num2 = ((x2 - x1) * (y1 - y3)) - ((y2 - y1) * (x1 - x3))
+
+    num = num1
+
+    if denom != 0: 
+        x = x1 + ((num / denom) * (x2 - x1))
+        y = y1 + ((num / denom) * (y2 - y1))
+        return Point(x, y)
+    return Point(NaN, NaN)
+
+def dot(s1, s2):
+    return s1.delta_x() * s2.delta_x() + s1.delta_y() * s2.delta_y()