1 #!/usr/bin/env python
2 '''
3 Copyright (C) 2007 Tavmjong Bah, tavmjong@free.fr
4 Copyright (C) 2006 Georg Wiora, xorx@quarkbox.de
5 Copyright (C) 2006 Johan Engelen, johan@shouraizou.nl
6 Copyright (C) 2005 Aaron Spike, aaron@ekips.org
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 Changes:
23 * This program is a modified version of wavy.py by Aaron Spike.
24 * 22-Dec-2006: Wiora : Added axis and isotropic scaling
25 * 21-Jun-2007: Tavmjong: Added polar coordinates
27 '''
28 import inkex, simplepath, simplestyle
29 from math import *
30 from random import *
32 def drawfunction(xstart, xend, ybottom, ytop, samples, width, height, left, bottom,
33 fx = "sin(x)", fpx = "cos(x)", fponum = True, times2pi = False, polar = False, isoscale = True, drawaxis = True):
35 if times2pi == True:
36 xstart = 2 * pi * xstart
37 xend = 2 * pi * xend
39 # coords and scales based on the source rect
40 scalex = width / (xend - xstart)
41 xoff = left
42 coordx = lambda x: (x - xstart) * scalex + xoff #convert x-value to coordinate
43 if polar : # Set scale so that left side of rectangle is -1, right side is +1.
44 # (We can't use xscale for both range and scale.)
45 centerx = left + width/2.0
46 polar_scalex = width/2.0
47 coordx = lambda x: x * polar_scalex + centerx #convert x-value to coordinate
49 scaley = height / (ytop - ybottom)
50 yoff = bottom
51 coordy = lambda y: (ybottom - y) * scaley + yoff #convert y-value to coordinate
53 # Check for isotropic scaling and use smaller of the two scales, correct ranges
54 if isoscale and not polar:
55 if scaley<scalex:
56 # compute zero location
57 xzero = coordx(0)
58 # set scale
59 scalex = scaley
60 # correct x-offset
61 xstart = (left-xzero)/scalex
62 xend = (left+width-xzero)/scalex
63 else :
64 # compute zero location
65 yzero = coordy(0)
66 # set scale
67 scaley = scalex
68 # correct x-offset
69 ybottom = (yzero-bottom)/scaley
70 ytop = (bottom+height-yzero)/scaley
72 # functions specified by the user
73 try:
74 if fx != "":
75 f = eval('lambda x: ' + fx.strip('"'))
76 if fpx != "":
77 fp = eval('lambda x: ' + fpx.strip('"'))
78 # handle incomplete/invalid function gracefully
79 except SyntaxError:
80 return []
82 # step is the distance between nodes on x
83 step = (xend - xstart) / (samples-1)
84 third = step / 3.0
85 ds = step * 0.001 # Step used in calculating derivatives
87 a = [] # path array
88 # add axis
89 if drawaxis :
90 # check for visibility of x-axis
91 if ybottom<=0 and ytop>=0:
92 # xaxis
93 a.append(['M ',[left, coordy(0)]])
94 a.append([' l ',[width, 0]])
95 # check for visibility of y-axis
96 if xstart<=0 and xend>=0:
97 # xaxis
98 a.append([' M ',[coordx(0),bottom]])
99 a.append([' l ',[0, -height]])
101 # initialize function and derivative for 0;
102 # they are carried over from one iteration to the next, to avoid extra function calculations.
103 x0 = xstart
104 y0 = f(xstart)
105 if polar :
106 xp0 = y0 * cos( x0 )
107 yp0 = y0 * sin( x0 )
108 x0 = xp0
109 y0 = yp0
110 if fponum or polar: # numerical derivative, using 0.001*step as the small differential
111 x1 = xstart + ds # Second point AFTER first point (Good for first point)
112 y1 = f(x1)
113 if polar :
114 xp1 = y1 * cos( x1 )
115 yp1 = y1 * sin( x1 )
116 x1 = xp1
117 y1 = yp1
118 dx0 = (x1 - x0)/ds
119 dy0 = (y1 - y0)/ds
120 else: # derivative given by the user
121 dx0 = 1 # Only works for rectangular coordinates
122 dy0 = fp(xstart)
124 # Start curve
125 a.append([' M ',[coordx(x0), coordy(y0)]]) # initial moveto
127 for i in range(int(samples-1)):
128 x1 = (i+1) * step + xstart
129 x2 = x1 - ds # Second point BEFORE first point (Good for last point)
130 y1 = f(x1)
131 y2 = f(x2)
132 if polar :
133 xp1 = y1 * cos( x1 )
134 yp1 = y1 * sin( x1 )
135 xp2 = y2 * cos( x2 )
136 yp2 = y2 * sin( x2 )
137 x1 = xp1
138 y1 = yp1
139 x2 = xp2
140 y2 = yp2
141 if fponum or polar: # numerical derivative
142 dx1 = (x1 - x2)/ds
143 dy1 = (y1 - y2)/ds
144 else: # derivative given by the user
145 dx1 = 1 # Only works for rectangular coordinates
146 dy1 = fp(x1)
147 # create curve
148 a.append([' C ',
149 [coordx(x0 + (dx0 * third)), coordy(y0 + (dy0 * third)),
150 coordx(x1 - (dx1 * third)), coordy(y1 - (dy1 * third)),
151 coordx(x1), coordy(y1)]
152 ])
153 x0 = x1 # Next segment's start is this segments end
154 y0 = y1
155 dx0 = dx1 # Assume the function is smooth everywhere, so carry over the derivative too
156 dy0 = dy1
157 return a
159 class FuncPlot(inkex.Effect):
160 def __init__(self):
161 inkex.Effect.__init__(self)
162 self.OptionParser.add_option("--xstart",
163 action="store", type="float",
164 dest="xstart", default=0.0,
165 help="Start x-value")
166 self.OptionParser.add_option("--xend",
167 action="store", type="float",
168 dest="xend", default=1.0,
169 help="End x-value")
170 self.OptionParser.add_option("--times2pi",
171 action="store", type="inkbool",
172 dest="times2pi", default=True,
173 help="Multiply x-range by 2*pi")
174 self.OptionParser.add_option("--polar",
175 action="store", type="inkbool",
176 dest="polar", default=False,
177 help="Plot using polar coordinates")
178 self.OptionParser.add_option("--ybottom",
179 action="store", type="float",
180 dest="ybottom", default=-1.0,
181 help="y-value of rectangle's bottom")
182 self.OptionParser.add_option("--ytop",
183 action="store", type="float",
184 dest="ytop", default=1.0,
185 help="y-value of rectangle's top")
186 self.OptionParser.add_option("-s", "--samples",
187 action="store", type="int",
188 dest="samples", default=8,
189 help="Samples")
190 self.OptionParser.add_option("--fofx",
191 action="store", type="string",
192 dest="fofx", default="sin(x)",
193 help="f(x) for plotting")
194 self.OptionParser.add_option("--fponum",
195 action="store", type="inkbool",
196 dest="fponum", default=True,
197 help="Calculate the first derivative numerically")
198 self.OptionParser.add_option("--fpofx",
199 action="store", type="string",
200 dest="fpofx", default="cos(x)",
201 help="f'(x) for plotting")
202 self.OptionParser.add_option("--remove",
203 action="store", type="inkbool",
204 dest="remove", default=True,
205 help="If True, source rectangle is removed")
206 self.OptionParser.add_option("--isoscale",
207 action="store", type="inkbool",
208 dest="isoscale", default=True,
209 help="If True, isotropic scaling is used")
210 self.OptionParser.add_option("--drawaxis",
211 action="store", type="inkbool",
212 dest="drawaxis", default=True,
213 help="If True, axis are drawn")
214 self.OptionParser.add_option("--tab",
215 action="store", type="string",
216 dest="tab", default="sampling",
217 help="The selected UI-tab when OK was pressed")
218 self.OptionParser.add_option("--funcplotuse",
219 action="store", type="string",
220 dest="funcplotuse", default="",
221 help="dummy")
222 self.OptionParser.add_option("--pythonfunctions",
223 action="store", type="string",
224 dest="pythonfunctions", default="",
225 help="dummy")
227 def effect(self):
228 for id, node in self.selected.iteritems():
229 if node.tag == inkex.addNS('rect','svg'):
230 # create new path with basic dimensions of selected rectangle
231 newpath = inkex.etree.Element(inkex.addNS('path','svg'))
232 x = float(node.get('x'))
233 y = float(node.get('y'))
234 w = float(node.get('width'))
235 h = float(node.get('height'))
237 #copy attributes of rect
238 s = node.get('style')
239 if s:
240 newpath.set('style', s)
242 t = node.get('transform')
243 if t:
244 newpath.set('transform', t)
246 # top and bottom were exchanged
247 newpath.set('d', simplepath.formatPath(
248 drawfunction(self.options.xstart,
249 self.options.xend,
250 self.options.ybottom,
251 self.options.ytop,
252 self.options.samples,
253 w,h,x,y+h,
254 self.options.fofx,
255 self.options.fpofx,
256 self.options.fponum,
257 self.options.times2pi,
258 self.options.polar,
259 self.options.isoscale,
260 self.options.drawaxis)))
261 newpath.set('title', self.options.fofx)
263 #newpath.setAttribute('desc', '!func;' + self.options.fofx + ';'
264 # + self.options.fpofx + ';'
265 # + `self.options.fponum` + ';'
266 # + `self.options.xstart` + ';'
267 # + `self.options.xend` + ';'
268 # + `self.options.samples`)
270 # add path into SVG structure
271 node.getparent().append(newpath)
272 # option wether to remove the rectangle or not.
273 if self.options.remove:
274 node.getparent().remove(node)
276 if __name__ == '__main__':
277 e = FuncPlot()
278 e.affect()
281 # vim: expandtab shiftwidth=4 tabstop=8 softtabstop=4 encoding=utf-8 textwidth=99