funcplot.py revision ff1686586f92b1d23d6303765a9cffee59fd7fef
#!/usr/bin/env python
'''
Copyright (C) 2006 Johan Engelen, johan@shouraizou.nl
Copyright (C) 2005 Aaron Spike, aaron@ekips.org
This program 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.
This program 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 this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
This program is a modified version of wavy.py by Aaron Spike.
'''
import inkex, simplepath, simplestyle
from math import *
from random import *
def drawfunction(xstart, xend, ybottom, ytop, samples, width, height, left, top,
fx = "sin(x)", fpx = "cos(x)", fponum = True, times2pi = False):
if times2pi == True:
xstart = 2 * pi * xstart
xend = 2 * pi * xend
# step is the distance between nodes on x
step = (xend - xstart) / (samples-1)
third = step / 3.0
# coords and scales based on the source rect
scalex = width / (xend - xstart)
xoff = left
coordx = lambda x: (x - xstart) * scalex + xoff #convert x-value to coordinate
scaley = height / (ytop - ybottom)
yoff = top
coordy = lambda y: (ytop-y) * scaley + yoff #convert y-value to coordinate
# functions specified by the user
if fx != "":
f = eval('lambda x: ' + fx)
if fpx != "":
fp = eval('lambda x: ' + fpx)
# initialize function and derivative for 0;
# they are carried over from one iteration to the next, to avoid extra function calculations
y0 = f(xstart)
if fponum == True: # numerical derivative, using 0.001*step as the small differential
d0 = (f(xstart + 0.001*step) - y0)/(0.001*step)
else: # derivative given by the user
d0 = fp(xstart)
a = [] # path array
a.append(['M',[coordx(xstart), coordy(y0)]]) # initial moveto
for i in range(int(samples-1)):
x = (i+1) * step + xstart
y1 = f(x)
if fponum == True: # numerical derivative
d1 = (y1 - f(x - 0.001*step))/(0.001*step)
else: # derivative given by the user
d1 = fp(x)
# create curve
a.append(['C',[coordx(x - step + third), coordy(y0 + (d0 * third)),
coordx(x - third), coordy(y1 - (d1 * third)),
coordx(x), coordy(y1)]])
y0 = y1 # next segment's y0 is this segment's y1
d0 = d1 # we assume the function is smooth everywhere, so carry over the derivative too
return a
class FuncPlot(inkex.Effect):
def __init__(self):
inkex.Effect.__init__(self)
self.OptionParser.add_option("--xstart",
action="store", type="float",
dest="xstart", default=0.0,
help="Start x-value")
self.OptionParser.add_option("--xend",
action="store", type="float",
dest="xend", default=1.0,
help="End x-value")
self.OptionParser.add_option("--times2pi",
action="store", type="inkbool",
dest="times2pi", default=True,
help="Multiply x-range by 2*pi")
self.OptionParser.add_option("--ybottom",
action="store", type="float",
dest="ybottom", default=-1.0,
help="y-value of rectangle's bottom")
self.OptionParser.add_option("--ytop",
action="store", type="float",
dest="ytop", default=1.0,
help="y-value of rectangle's top")
self.OptionParser.add_option("-s", "--samples",
action="store", type="int",
dest="samples", default=8,
help="Samples")
self.OptionParser.add_option("--fofx",
action="store", type="string",
dest="fofx", default="sin(x)",
help="f(x) for plotting")
self.OptionParser.add_option("--fponum",
action="store", type="inkbool",
dest="fponum", default=True,
help="Calculate the first derivative numerically")
self.OptionParser.add_option("--fpofx",
action="store", type="string",
dest="fpofx", default="cos(x)",
help="f'(x) for plotting")
self.OptionParser.add_option("--tab",
action="store", type="string",
dest="tab", default="sampling",
help="The selected UI-tab when OK was pressed")
self.OptionParser.add_option("--pythonfunctions",
action="store", type="string",
dest="pythonfunctions", default="",
help="dummy")
def effect(self):
for id, node in self.selected.iteritems():
if node.tagName == 'rect':
# create new path with basic dimensions of selected rectangle
newpath = self.document.createElement('svg:path')
x = float(node.attributes.getNamedItem('x').value)
y = float(node.attributes.getNamedItem('y').value)
w = float(node.attributes.getNamedItem('width').value)
h = float(node.attributes.getNamedItem('height').value)
#copy attributes of rect
s = node.attributes.getNamedItem('style').value
newpath.setAttribute('style', s)
try:
t = node.attributes.getNamedItem('transform').value
newpath.setAttribute('transform', t)
except AttributeError:
pass
newpath.setAttribute('d', simplepath.formatPath(
drawfunction(self.options.xstart,
self.options.xend,
self.options.ybottom,
self.options.ytop,
self.options.samples,
w,h,x,y,
self.options.fofx,
self.options.fpofx,
self.options.fponum,
self.options.times2pi)))
newpath.setAttribute('title', self.options.fofx)
#newpath.setAttribute('desc', '!func;' + self.options.fofx + ';'
# + self.options.fpofx + ';'
# + `self.options.fponum` + ';'
# + `self.options.xstart` + ';'
# + `self.options.xend` + ';'
# + `self.options.samples`)
# add path into SVG structure
node.parentNode.appendChild(newpath)
# TODO: make an option wether to remove the rectangle or not.
node.parentNode.removeChild(node)
e = FuncPlot()
e.affect()