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simpletransform.py

#!/usr/bin/env python
'''
Copyright (C) 2006 Jean-Francois Barraud, barraud@math.univ-lille1.fr

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
barraud@math.univ-lille1.fr

This code defines several functions to make handling of transform
attribute easier.
'''
import inkex, cubicsuperpath, bezmisc, simplestyle
import copy, math, re

def parseTransform(transf,mat=[[1.0,0.0,0.0],[0.0,1.0,0.0]]):
    if transf=="" or transf==None:
        return(mat)
    result=re.match("(translate|scale|rotate|skewX|skewY|matrix)\(([^)]*)\)",transf)
#-- translate --
    if result.group(1)=="translate":
        args=result.group(2).split(",")
        dx=float(args[0])
        if len(args)==1:
            dy=0.0
        else:
            dy=float(args[1])
        matrix=[[1,0,dx],[0,1,dy]]
#-- scale --
    if result.groups(1)=="scale":
        args=result.group(2).split(",")
        sx=float(args[0])
        if len(args)==1:
            sy=sx
        else:
            sy=float(args[1])
        matrix=[[sx,0,0],[0,sy,0]]
#-- rotate --
    if result.groups(1)=="rotate":
        args=result.group(2).split(",")
        a=float(args[0])*math.pi/180
        if len(args)==1:
            cx,cy=(0.0,0.0)
        else:
            cx,cy=args[1:]
        matrix=[[math.cos(a),-math.sin(a),cx],[math.sin(a),math.cos(a),cy]]
#-- skewX --
    if result.groups(1)=="skewX":
        a=float(result.group(2))*math.pi/180
        matrix=[[1,math.tan(a),0],[0,1,0]]
#-- skewX --
    if result.groups(1)=="skewX":
        a=float(result.group(2))*math.pi/180
        matrix=[[1,0,0],[math.tan(a),1,0]]
#-- matrix --
    if result.group(1)=="matrix":
        a11,a21,a12,a22,v1,v2=result.group(2).split(",")
        matrix=[[float(a11),float(a12),float(v1)],[float(a21),float(a22),float(v2)]]
    
    matrix=composeTransform(mat,matrix)
    if result.end()<len(transf):
        return(parseTransform(transf[result.end():],matrix))
    else:
        return matrix

def formatTransform(mat):
    return("matrix(%f,%f,%f,%f,%f,%f)"%(mat[0][0],mat[1][0],mat[0][1],mat[1][1],mat[0][2],mat[1][2]))

def composeTransform(M1,M2):
    a11=M1[0][0]*M2[0][0]+M1[0][1]*M2[1][0]
    a12=M1[0][0]*M2[0][1]+M1[0][1]*M2[1][1]
    a21=M1[1][0]*M2[0][0]+M1[1][1]*M2[1][0]
    a22=M1[1][0]*M2[0][1]+M1[1][1]*M2[1][1]

    v1=M1[0][0]*M2[0][2]+M1[0][1]*M2[1][2]+M1[0][2]
    v2=M1[1][0]*M2[0][2]+M1[1][1]*M2[1][2]+M1[1][2]
    return [[a11,a12,v1],[a21,a22,v2]]

def applyTransformToNode(mat,node):
    m=parseTransform(node.get("transform"))
    newtransf=formatTransform(composeTransform(mat,m))
    node.set("transform", newtransf)

def applyTransformToPoint(mat,pt):
    x=mat[0][0]*pt[0]+mat[0][1]*pt[1]+mat[0][2]
    y=mat[1][0]*pt[0]+mat[1][1]*pt[1]+mat[1][2]
    pt[0]=x
    pt[1]=y

def applyTransformToPath(mat,path):
    for comp in path:
        for ctl in comp:
            for pt in ctl:
                applyTransformToPoint(mat,pt)

def fuseTransform(node):
    if node.get('d')==None:
        #FIX ME: how do you raise errors?
        raise AssertionError, 'can not fuse "transform" of elements that have no "d" attribute'
    t = node.get("transform")
    if t == None:
        return
    m = parseTransform(t)
    d = node.get('d')
    p = cubicsuperpath.parsePath(d)
    applyTransformToPath(m,p)
    node.set('d', cubicsuperpath.formatPath(p))
    del node.attrib["transform"]

####################################################################
##-- Some functions to compute a rough bbox of a given list of objects.
##-- this should be shipped out in an separate file...

def boxunion(b1,b2):
    if b1 is None:
        return b2
    elif b2 is None:
        return b1    
    else:
        return((min(b1[0],b2[0]),max(b1[1],b2[1]),min(b1[2],b2[2]),max(b1[3],b2[3])))

def roughBBox(path):
    xmin,xMax,ymin,yMax=path[0][0][0][0],path[0][0][0][0],path[0][0][0][1],path[0][0][0][1]
    for pathcomp in path:
        for ctl in pathcomp:
           for pt in ctl:
               xmin=min(xmin,pt[0])
               xMax=max(xMax,pt[0])
               ymin=min(ymin,pt[1])
               yMax=max(yMax,pt[1])
    return xmin,xMax,ymin,yMax

def computeBBox(aList,mat=[[1,0,0],[0,1,0]]):
    bbox=None
    for node in aList:
        m = parseTransform(node.get('transform'))
        m = composeTransform(mat,m)
        #TODO: text not supported!
        if node.get("d"):
            d = node.get('d')
            p = cubicsuperpath.parsePath(d)
            applyTransformToPath(m,p)
            bbox=boxunion(roughBBox(p),bbox)

        if  node.tag == inkex.addNS('use','svg') or node.tag=='use':
            refid=node.get(inkex.addNS('href','xlink'))
            path = '//*[@id="%s"]' % refid[1:]
            refnode = node.getroottree().xpath(path, namespaces=inkex.NSS)
            bbox=boxunion(computeBBox(refnode,m),bbox)
            
        bbox=boxunion(computeBBox(node,m),bbox)
    return bbox



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