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 if fx != "":
74 f = eval('lambda x: ' + fx.strip('"'))
75 if fpx != "":
76 fp = eval('lambda x: ' + fpx.strip('"'))
78 # step is the distance between nodes on x
79 step = (xend - xstart) / (samples-1)
80 third = step / 3.0
81 ds = step * 0.001 # Step used in calculating derivatives
83 a = [] # path array
84 # add axis
85 if drawaxis :
86 # check for visibility of x-axis
87 if ybottom<=0 and ytop>=0:
88 # xaxis
89 a.append(['M ',[left, coordy(0)]])
90 a.append([' l ',[width, 0]])
91 # check for visibility of y-axis
92 if xstart<=0 and xend>=0:
93 # xaxis
94 a.append([' M ',[coordx(0),bottom]])
95 a.append([' l ',[0, -height]])
97 # initialize function and derivative for 0;
98 # they are carried over from one iteration to the next, to avoid extra function calculations.
99 x0 = xstart
100 y0 = f(xstart)
101 if polar :
102 xp0 = y0 * cos( x0 )
103 yp0 = y0 * sin( x0 )
104 x0 = xp0
105 y0 = yp0
106 if fponum or polar: # numerical derivative, using 0.001*step as the small differential
107 x1 = xstart + ds # Second point AFTER first point (Good for first point)
108 y1 = f(x1)
109 if polar :
110 xp1 = y1 * cos( x1 )
111 yp1 = y1 * sin( x1 )
112 x1 = xp1
113 y1 = yp1
114 dx0 = (x1 - x0)/ds
115 dy0 = (y1 - y0)/ds
116 else: # derivative given by the user
117 dx0 = 0 # Only works for rectangular coordinates
118 dy0 = fp(xstart)
120 # Start curve
121 a.append([' M ',[coordx(x0), coordy(y0)]]) # initial moveto
123 for i in range(int(samples-1)):
124 x1 = (i+1) * step + xstart
125 x2 = x1 - ds # Second point BEFORE first point (Good for last point)
126 y1 = f(x1)
127 y2 = f(x2)
128 if polar :
129 xp1 = y1 * cos( x1 )
130 yp1 = y1 * sin( x1 )
131 xp2 = y2 * cos( x2 )
132 yp2 = y2 * sin( x2 )
133 x1 = xp1
134 y1 = yp1
135 x2 = xp2
136 y2 = yp2
137 if fponum or polar: # numerical derivative
138 dx1 = (x1 - x2)/ds
139 dy1 = (y1 - y2)/ds
140 else: # derivative given by the user
141 dx1 = 0 # Only works for rectangular coordinates
142 dy1 = fp(x1)
143 # create curve
144 a.append([' C ',
145 [coordx(x0 + (dx0 * third)), coordy(y0 + (dy0 * third)),
146 coordx(x1 - (dx1 * third)), coordy(y1 - (dy1 * third)),
147 coordx(x1), coordy(y1)]
148 ])
149 x0 = x1 # Next segment's start is this segments end
150 y0 = y1
151 dx0 = dx1 # Assume the function is smooth everywhere, so carry over the derivative too
152 dy0 = dy1
153 return a
155 class FuncPlot(inkex.Effect):
156 def __init__(self):
157 inkex.Effect.__init__(self)
158 self.OptionParser.add_option("--xstart",
159 action="store", type="float",
160 dest="xstart", default=0.0,
161 help="Start x-value")
162 self.OptionParser.add_option("--xend",
163 action="store", type="float",
164 dest="xend", default=1.0,
165 help="End x-value")
166 self.OptionParser.add_option("--times2pi",
167 action="store", type="inkbool",
168 dest="times2pi", default=True,
169 help="Multiply x-range by 2*pi")
170 self.OptionParser.add_option("--polar",
171 action="store", type="inkbool",
172 dest="polar", default=False,
173 help="Plot using polar coordinates")
174 self.OptionParser.add_option("--ybottom",
175 action="store", type="float",
176 dest="ybottom", default=-1.0,
177 help="y-value of rectangle's bottom")
178 self.OptionParser.add_option("--ytop",
179 action="store", type="float",
180 dest="ytop", default=1.0,
181 help="y-value of rectangle's top")
182 self.OptionParser.add_option("-s", "--samples",
183 action="store", type="int",
184 dest="samples", default=8,
185 help="Samples")
186 self.OptionParser.add_option("--fofx",
187 action="store", type="string",
188 dest="fofx", default="sin(x)",
189 help="f(x) for plotting")
190 self.OptionParser.add_option("--fponum",
191 action="store", type="inkbool",
192 dest="fponum", default=True,
193 help="Calculate the first derivative numerically")
194 self.OptionParser.add_option("--fpofx",
195 action="store", type="string",
196 dest="fpofx", default="cos(x)",
197 help="f'(x) for plotting")
198 self.OptionParser.add_option("--remove",
199 action="store", type="inkbool",
200 dest="remove", default=True,
201 help="If True, source rectangle is removed")
202 self.OptionParser.add_option("--isoscale",
203 action="store", type="inkbool",
204 dest="isoscale", default=True,
205 help="If True, isotropic scaling is used")
206 self.OptionParser.add_option("--drawaxis",
207 action="store", type="inkbool",
208 dest="drawaxis", default=True,
209 help="If True, axis are drawn")
210 self.OptionParser.add_option("--tab",
211 action="store", type="string",
212 dest="tab", default="sampling",
213 help="The selected UI-tab when OK was pressed")
214 self.OptionParser.add_option("--funcplotuse",
215 action="store", type="string",
216 dest="funcplotuse", default="",
217 help="dummy")
218 self.OptionParser.add_option("--pythonfunctions",
219 action="store", type="string",
220 dest="pythonfunctions", default="",
221 help="dummy")
223 def effect(self):
224 for id, node in self.selected.iteritems():
225 if node.tag == inkex.addNS('rect','svg'):
226 # create new path with basic dimensions of selected rectangle
227 newpath = inkex.etree.Element(inkex.addNS('path','svg'))
228 x = float(node.get('x'))
229 y = float(node.get('y'))
230 w = float(node.get('width'))
231 h = float(node.get('height'))
233 #copy attributes of rect
234 s = node.get('style')
235 if s:
236 newpath.set('style', s)
238 t = node.get('transform')
239 if t:
240 newpath.set('transform', t)
242 # top and bottom were exchanged
243 newpath.set('d', simplepath.formatPath(
244 drawfunction(self.options.xstart,
245 self.options.xend,
246 self.options.ybottom,
247 self.options.ytop,
248 self.options.samples,
249 w,h,x,y+h,
250 self.options.fofx,
251 self.options.fpofx,
252 self.options.fponum,
253 self.options.times2pi,
254 self.options.polar,
255 self.options.isoscale,
256 self.options.drawaxis)))
257 newpath.set('title', self.options.fofx)
259 #newpath.setAttribute('desc', '!func;' + self.options.fofx + ';'
260 # + self.options.fpofx + ';'
261 # + `self.options.fponum` + ';'
262 # + `self.options.xstart` + ';'
263 # + `self.options.xend` + ';'
264 # + `self.options.samples`)
266 # add path into SVG structure
267 node.getparent().append(newpath)
268 # option wether to remove the rectangle or not.
269 if self.options.remove:
270 node.getparent().remove(node)
272 e = FuncPlot()
273 e.affect()