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interp.py

#!/usr/bin/env python 
'''
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
'''
import inkex, cubicsuperpath, simplestyle, copy, math, re, bezmisc

uuconv = {'in':90.0, 'pt':1.25, 'px':1, 'mm':3.5433070866, 'cm':35.433070866, 'pc':15.0}
def numsegs(csp):
    return sum([len(p)-1 for p in csp])
def interpcoord(v1,v2,p):
    return v1+((v2-v1)*p)
def interppoints(p1,p2,p):
    return [interpcoord(p1[0],p2[0],p),interpcoord(p1[1],p2[1],p)]
def pointdistance((x1,y1),(x2,y2)):
    return math.sqrt(((x2 - x1) ** 2) + ((y2 - y1) ** 2))
def bezlenapprx(sp1, sp2):
    return pointdistance(sp1[1], sp1[2]) + pointdistance(sp1[2], sp2[0]) + pointdistance(sp2[0], sp2[1])
def tpoint((x1,y1), (x2,y2), t = 0.5):
    return [x1+t*(x2-x1),y1+t*(y2-y1)]
def cspbezsplit(sp1, sp2, t = 0.5):
    m1=tpoint(sp1[1],sp1[2],t)
    m2=tpoint(sp1[2],sp2[0],t)
    m3=tpoint(sp2[0],sp2[1],t)
    m4=tpoint(m1,m2,t)
    m5=tpoint(m2,m3,t)
    m=tpoint(m4,m5,t)
    return [[sp1[0][:],sp1[1][:],m1], [m4,m,m5], [m3,sp2[1][:],sp2[2][:]]]
def cspbezsplitatlength(sp1, sp2, l = 0.5, tolerance = 0.001):
    bez = (sp1[1][:],sp1[2][:],sp2[0][:],sp2[1][:])
    t = bezmisc.beziertatlength(bez, l, tolerance)
    return cspbezsplit(sp1, sp2, t)
def cspseglength(sp1,sp2, tolerance = 0.001):
    bez = (sp1[1][:],sp1[2][:],sp2[0][:],sp2[1][:])
    return bezmisc.bezierlength(bez, tolerance)    
def csplength(csp):
    total = 0
    lengths = []
    for sp in csp:
        lengths.append([])
        for i in xrange(1,len(sp)):
            l = cspseglength(sp[i-1],sp[i])
            lengths[-1].append(l)
            total += l            
    return lengths, total
def styleunittouu(string):
    unit = re.compile('(%s)$' % '|'.join(uuconv.keys()))
    param = re.compile(r'(([-+]?[0-9]+(\.[0-9]*)?|[-+]?\.[0-9]+)([eE][-+]?[0-9]+)?)')

    p = param.match(string)
    u = unit.search(string)    
    if p:
        retval = float(p.string[p.start():p.end()])
    else:
        retval = 0.0
    if u:
        try:
            return retval * uuconv[u.string[u.start():u.end()]]
        except KeyError:
            pass
    return retval
    
def tweenstylefloat(property, start, end, time):
    sp = float(start[property])
    ep = float(end[property])
    return str(sp + (time * (ep - sp)))
def tweenstyleunit(property, start, end, time):
    sp = styleunittouu(start[property])
    ep = styleunittouu(end[property])
    return str(sp + (time * (ep - sp)))
def tweenstylecolor(property, start, end, time):
    sr,sg,sb = parsecolor(start[property])
    er,eg,eb = parsecolor(end[property])
    return '#%s%s%s' % (tweenhex(time,sr,er),tweenhex(time,sg,eg),tweenhex(time,sb,eb))
def tweenhex(time,s,e):
    s = float(int(s,16))
    e = float(int(e,16))
    retval = hex(int(math.floor(s + (time * (e - s)))))[2:]
    if len(retval)==1:
        retval = '0%s' % retval
    return retval
def parsecolor(c):
    r,g,b = '0','0','0'
    if c[:1]=='#':
        if len(c)==4:
            r,g,b = c[1:2],c[2:3],c[3:4]
        elif len(c)==7:
            r,g,b = c[1:3],c[3:5],c[5:7]
    return r,g,b

class Interp(inkex.Effect):
    def __init__(self):
        inkex.Effect.__init__(self)
        self.OptionParser.add_option("-e", "--exponent",
                        action="store", type="float", 
                        dest="exponent", default=0.0,
                        help="values other than zero give non linear interpolation")
        self.OptionParser.add_option("-s", "--steps",
                        action="store", type="int", 
                        dest="steps", default=5,
                        help="number of interpolation steps")
        self.OptionParser.add_option("-m", "--method",
                        action="store", type="int", 
                        dest="method", default=2,
                        help="method of interpolation")
        self.OptionParser.add_option("-d", "--dup",
                        action="store", type="inkbool", 
                        dest="dup", default=True,
                        help="duplicate endpaths")    
        self.OptionParser.add_option("--style",
                        action="store", type="inkbool", 
                        dest="style", default=True,
                        help="try interpolation of some style properties")    
    def effect(self):
        exponent = self.options.exponent
        if exponent>= 0:
            exponent = 1.0 + exponent
        else:
            exponent = 1.0/(1.0 - exponent)
        steps = [1.0/(self.options.steps + 1.0)]
        for i in range(self.options.steps - 1):
            steps.append(steps[0] + steps[-1])
        steps = [step**exponent for step in steps]
            
        paths = {}            
        styles = {}
        for id in self.options.ids:
            node = self.selected[id]
            if node.tagName =='path':
                paths[id] = cubicsuperpath.parsePath(node.attributes.getNamedItem('d').value)
                styles[id] = simplestyle.parseStyle(node.attributes.getNamedItem('style').value)
            else:
                self.options.ids.remove(id)

        for i in range(1,len(self.options.ids)):
            start = copy.deepcopy(paths[self.options.ids[i-1]])
            end = copy.deepcopy(paths[self.options.ids[i]])
            sst = copy.deepcopy(styles[self.options.ids[i-1]])
            est = copy.deepcopy(styles[self.options.ids[i]])
            basestyle = copy.deepcopy(sst)

            #prepare for experimental style tweening
            if self.options.style:
                dostroke = True
                dofill = True
                styledefaults = {'opacity':'1.0', 'stroke-opacity':'1.0', 'fill-opacity':'1.0',
                        'stroke-width':'1.0', 'stroke':'none', 'fill':'none'}
                for key in styledefaults.keys():
                    sst.setdefault(key,styledefaults[key])
                    est.setdefault(key,styledefaults[key])
                isnotplain = lambda x: not (x=='none' or x[:1]=='#')
                if isnotplain(sst['stroke']) or isnotplain(est['stroke']) or (sst['stroke']=='none' and est['stroke']=='none'):
                    dostroke = False
                if isnotplain(sst['fill']) or isnotplain(est['fill']) or (sst['fill']=='none' and est['fill']=='none'):
                    dofill = False
                if dostroke:
                    if sst['stroke']=='none':
                        sst['stroke-width'] = '0.0'
                        sst['stroke-opacity'] = '0.0'
                        sst['stroke'] = est['stroke'] 
                    elif est['stroke']=='none':
                        est['stroke-width'] = '0.0'
                        est['stroke-opacity'] = '0.0'
                        est['stroke'] = sst['stroke'] 
                if dofill:
                    if sst['fill']=='none':
                        sst['fill-opacity'] = '0.0'
                        sst['fill'] = est['fill'] 
                    elif est['fill']=='none':
                        est['fill-opacity'] = '0.0'
                        est['fill'] = sst['fill'] 

                    

            if self.options.method == 2:
                #subdivide both paths into segments of relatively equal lengths
                slengths, stotal = csplength(start)
                elengths, etotal = csplength(end)
                lengths = {}
                t = 0
                for sp in slengths:
                    for l in sp:
                        t += l / stotal
                        lengths.setdefault(t,0)
                        lengths[t] += 1
                t = 0
                for sp in elengths:
                    for l in sp:
                        t += l / etotal
                        lengths.setdefault(t,0)
                        lengths[t] += -1
                sadd = [k for (k,v) in lengths.iteritems() if v < 0]
                sadd.sort()
                eadd = [k for (k,v) in lengths.iteritems() if v > 0]
                eadd.sort()

                t = 0
                s = [[]]
                for sp in slengths:
                    if not start[0]:
                        s.append(start.pop(0))
                    s[-1].append(start[0].pop(0))
                    for l in sp:
                        pt = t
                        t += l / stotal
                        if sadd and t > sadd[0]:
                            while sadd and sadd[0] < t:
                                nt = (sadd[0] - pt) / (t - pt)
                                bezes = cspbezsplitatlength(s[-1][-1][:],start[0][0][:], nt)
                                s[-1][-1:] = bezes[:2]
                                start[0][0] = bezes[2]
                                pt = sadd.pop(0)
                        s[-1].append(start[0].pop(0))
                t = 0
                e = [[]]
                for sp in elengths:
                    if not end[0]:
                        e.append(end.pop(0))
                    e[-1].append(end[0].pop(0))
                    for l in sp:
                        pt = t
                        t += l / etotal
                        if eadd and t > eadd[0]:
                            while eadd and eadd[0] < t:
                                nt = (eadd[0] - pt) / (t - pt)
                                bezes = cspbezsplitatlength(e[-1][-1][:],end[0][0][:], nt)
                                e[-1][-1:] = bezes[:2]
                                end[0][0] = bezes[2]
                                pt = eadd.pop(0)
                        e[-1].append(end[0].pop(0))
                start = s[:]
                end = e[:]
            else:
                #which path has fewer segments?
                lengthdiff = numsegs(start) - numsegs(end)
                #swap shortest first
                if lengthdiff > 0:
                    start, end = end, start
                #subdivide the shorter path
                for x in range(abs(lengthdiff)):
                    maxlen = 0
                    subpath = 0
                    segment = 0
                    for y in range(len(start)):
                        for z in range(1, len(start[y])):
                            leng = bezlenapprx(start[y][z-1], start[y][z])
                            if leng > maxlen:
                                maxlen = leng
                                subpath = y
                                segment = z
                    sp1, sp2 = start[subpath][segment - 1:segment + 1]
                    start[subpath][segment - 1:segment + 1] = cspbezsplit(sp1, sp2)
                #if swapped, swap them back
                if lengthdiff > 0:
                    start, end = end, start
            
            #break paths so that corresponding subpaths have an equal number of segments
            s = [[]]
            e = [[]]
            while start and end:
                if start[0] and end[0]:
                    s[-1].append(start[0].pop(0))
                    e[-1].append(end[0].pop(0))
                elif end[0]:
                    s.append(start.pop(0))
                    e[-1].append(end[0][0])
                    e.append([end[0].pop(0)])
                elif start[0]:
                    e.append(end.pop(0))
                    s[-1].append(start[0][0])
                    s.append([start[0].pop(0)])
                else:
                    s.append(start.pop(0))
                    e.append(end.pop(0))
    
            if self.options.dup:
                steps = [0] + steps + [1]    
            #create an interpolated path for each interval
            group = self.document.createElement('svg:g')    
            self.current_layer.appendChild(group)
            for time in steps:
                interp = []
                #process subpaths
                for ssp,esp in zip(s, e):
                    if not (ssp or esp):
                        break
                    interp.append([])
                    #process superpoints
                    for sp,ep in zip(ssp, esp):
                        if not (sp or ep):
                            break
                        interp[-1].append([])
                        #process points
                        for p1,p2 in zip(sp, ep):
                            if not (sp or ep):
                                break
                            interp[-1][-1].append(interppoints(p1, p2, time))

                #remove final subpath if empty.
                if not interp[-1]:
                    del interp[-1]
                new = self.document.createElement('svg:path')

                #basic style tweening
                if self.options.style:
                    basestyle['opacity'] = tweenstylefloat('opacity',sst,est,time)
                    if dostroke:
                        basestyle['stroke-opacity'] = tweenstylefloat('stroke-opacity',sst,est,time)
                        basestyle['stroke-width'] = tweenstyleunit('stroke-width',sst,est,time)
                        basestyle['stroke'] = tweenstylecolor('stroke',sst,est,time)
                    if dofill:
                        basestyle['fill-opacity'] = tweenstylefloat('fill-opacity',sst,est,time)
                        basestyle['fill'] = tweenstylecolor('fill',sst,est,time)
                new.setAttribute('style', simplestyle.formatStyle(basestyle))
                new.setAttribute('d', cubicsuperpath.formatPath(interp))
                group.appendChild(new)

e = Interp()
e.affect()

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