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#!/usr/bin/env python
'''
Copyright (C) 2007 Tavmjong Bah, tavmjong@free.fr
Copyright (C) 2006 Georg Wiora, xorx@quarkbox.de
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
Changes:
* This program is a modified version of wavy.py by Aaron Spike.
* 22-Dec-2006: Wiora : Added axis and isotropic scaling
* 21-Jun-2007: Tavmjong: Added polar coordinates
'''
import inkex, simplepath, simplestyle
from math import *
from random import *
def drawfunction(xstart, xend, ybottom, ytop, samples, width, height, left, bottom,
fx = "sin(x)", fpx = "cos(x)", fponum = True, times2pi = False, polar = False, isoscale = True, drawaxis = True):
if times2pi == True:
xstart = 2 * pi * xstart
xend = 2 * pi * xend
# 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
if polar : # Set scale so that left side of rectangle is -1, right side is +1.
# (We can't use xscale for both range and scale.)
centerx = left + width/2.0
polar_scalex = width/2.0
coordx = lambda x: x * polar_scalex + centerx #convert x-value to coordinate
scaley = height / (ytop - ybottom)
yoff = bottom
coordy = lambda y: (ybottom - y) * scaley + yoff #convert y-value to coordinate
# Check for isotropic scaling and use smaller of the two scales, correct ranges
if isoscale and not polar:
if scaley<scalex:
# compute zero location
xzero = coordx(0)
# set scale
scalex = scaley
# correct x-offset
xstart = (left-xzero)/scalex
xend = (left+width-xzero)/scalex
else :
# compute zero location
yzero = coordy(0)
# set scale
scaley = scalex
# correct x-offset
ybottom = (yzero-bottom)/scaley
ytop = (bottom+height-yzero)/scaley
# functions specified by the user
try:
if fx != "":
f = eval('lambda x: ' + fx.strip('"'))
if fpx != "":
fp = eval('lambda x: ' + fpx.strip('"'))
# handle incomplete/invalid function gracefully
except SyntaxError:
return []
# step is the distance between nodes on x
step = (xend - xstart) / (samples-1)
third = step / 3.0
ds = step * 0.001 # Step used in calculating derivatives
a = [] # path array
# add axis
if drawaxis :
# check for visibility of x-axis
if ybottom<=0 and ytop>=0:
# xaxis
a.append(['M ',[left, coordy(0)]])
a.append([' l ',[width, 0]])
# check for visibility of y-axis
if xstart<=0 and xend>=0:
# xaxis
a.append([' M ',[coordx(0),bottom]])
a.append([' l ',[0, -height]])
# initialize function and derivative for 0;
# they are carried over from one iteration to the next, to avoid extra function calculations.
x0 = xstart
y0 = f(xstart)
if polar :
xp0 = y0 * cos( x0 )
yp0 = y0 * sin( x0 )
x0 = xp0
y0 = yp0
if fponum or polar: # numerical derivative, using 0.001*step as the small differential
x1 = xstart + ds # Second point AFTER first point (Good for first point)
y1 = f(x1)
if polar :
xp1 = y1 * cos( x1 )
yp1 = y1 * sin( x1 )
x1 = xp1
y1 = yp1
dx0 = (x1 - x0)/ds
dy0 = (y1 - y0)/ds
else: # derivative given by the user
dx0 = 1 # Only works for rectangular coordinates
dy0 = fp(xstart)
# Start curve
a.append([' M ',[coordx(x0), coordy(y0)]]) # initial moveto
for i in range(int(samples-1)):
x1 = (i+1) * step + xstart
x2 = x1 - ds # Second point BEFORE first point (Good for last point)
y1 = f(x1)
y2 = f(x2)
if polar :
xp1 = y1 * cos( x1 )
yp1 = y1 * sin( x1 )
xp2 = y2 * cos( x2 )
yp2 = y2 * sin( x2 )
x1 = xp1
y1 = yp1
x2 = xp2
y2 = yp2
if fponum or polar: # numerical derivative
dx1 = (x1 - x2)/ds
dy1 = (y1 - y2)/ds
else: # derivative given by the user
dx1 = 1 # Only works for rectangular coordinates
dy1 = fp(x1)
# create curve
a.append([' C ',
[coordx(x0 + (dx0 * third)), coordy(y0 + (dy0 * third)),
coordx(x1 - (dx1 * third)), coordy(y1 - (dy1 * third)),
coordx(x1), coordy(y1)]
])
x0 = x1 # Next segment's start is this segments end
y0 = y1
dx0 = dx1 # Assume the function is smooth everywhere, so carry over the derivative too
dy0 = dy1
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("--polar",
action="store", type="inkbool",
dest="polar", default=False,
help="Plot using polar coordinates")
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("--remove",
action="store", type="inkbool",
dest="remove", default=True,
help="If True, source rectangle is removed")
self.OptionParser.add_option("--isoscale",
action="store", type="inkbool",
dest="isoscale", default=True,
help="If True, isotropic scaling is used")
self.OptionParser.add_option("--drawaxis",
action="store", type="inkbool",
dest="drawaxis", default=True,
help="If True, axis are drawn")
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("--funcplotuse",
action="store", type="string",
dest="funcplotuse", default="",
help="dummy")
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.tag == inkex.addNS('rect','svg'):
# create new path with basic dimensions of selected rectangle
newpath = inkex.etree.Element(inkex.addNS('path','svg'))
x = float(node.get('x'))
y = float(node.get('y'))
w = float(node.get('width'))
h = float(node.get('height'))
#copy attributes of rect
s = node.get('style')
if s:
newpath.set('style', s)
t = node.get('transform')
if t:
newpath.set('transform', t)
# top and bottom were exchanged
newpath.set('d', simplepath.formatPath(
drawfunction(self.options.xstart,
self.options.xend,
self.options.ybottom,
self.options.ytop,
self.options.samples,
w,h,x,y+h,
self.options.fofx,
self.options.fpofx,
self.options.fponum,
self.options.times2pi,
self.options.polar,
self.options.isoscale,
self.options.drawaxis)))
newpath.set('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.getparent().append(newpath)
# option wether to remove the rectangle or not.
if self.options.remove:
node.getparent().remove(node)
if __name__ == '__main__':
e = FuncPlot()
e.affect()
# vim: expandtab shiftwidth=4 tabstop=8 softtabstop=4 encoding=utf-8 textwidth=99
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