#!/usr/bin/env python

# These two lines are only needed if you don't put the script directly into
# the installation directory
import sys
sys.path.append('/usr/share/inkscape/extensions')

import math

import subprocess  #We will call Inkscape to compute the bounding box

import inkex

from simplestyle import *

import simpletransform

class clonesPerspectiveEffect(inkex.Effect):
    """
Creates a series of clones shrinking to a vanishing point.
The vanishing point is the center of rotation, which must be dragged out to the
side before invocation.
    """
    def __init__(self):
        """
        Constructor.
        Defines the parms option of a script.
        """
        # Call the base class constructor.
        inkex.Effect.__init__(self)

        # Define string option "--what" with "-w" shortcut and default value "World".

        self.OptionParser.add_option('-n', '--num', action = 'store',
          type = 'int', dest = 'num', default = 5,
          help = 'Drag out center of rotation before calling')

        self.OptionParser.add_option('-r', '--ratio', action = 'store',
          type = 'float', dest = 'ratio', default = 0.9,
          help = 'Ratio of size of nearest neighbor to first.  Must be < 1')

    def effect(self):
        """
        Effect behaviour.
        Overrides base class' method.
        """

        global boxstring
        global seld

        svg = self.document.getroot()

        num = int( self.options.num )
        ratio = float( self.options.ratio )

        seld = self.selected

        if 1 != len(seld) :
            inkex.errormsg("Select exactly 1 thing. Group if necessary")
            sys.exit (1)
        id = seld.keys()[0]
        sel = seld[id]
        dic = sel.attrib

        try :
            tx = dic[inkex.addNS('transform-center-x','inkscape') ]
        except KeyError :
            tx = '0.'
        try :
            ty = dic[inkex.addNS('transform-center-y','inkscape') ]
        except KeyError : 
            ty = '0.'

        if float(tx) == 0. and float(ty) == 0. :
            inkex.errormsg("Center of rotation at center of object")
            sys.exit (1)

        thebox = simpletransform.computeBBox([sel])

        width =  thebox[1] - thebox[0]
        height = thebox[3] - thebox[2] 
        cx = float(thebox[0]) + 0.5 * width  #Find center of selected object
        cy = float(thebox[2]) + 0.5 * height #Find center of selected object
        tx = float(tx)
        ty = float(ty)
        crat = 1.0
        otx = tx
        oty = ty

        parent = self.getParentNode(sel)
        j = parent.index(sel)
        
        for i in range(num) :
            crat *= ratio
            tx *= ratio
            ty *= ratio
            att = {
                "id" : self.uniqueId("clone" + id),
                inkex.addNS('href','xlink') : "#" + id,
                inkex.addNS('transform-center-x','inkscape') : str(tx),
                inkex.addNS('transform-center-y','inkscape') : str(ty),
#            "x" : "0",
#            "y" : "0",
                'transform' : ("matrix(%f,0,0,%f,%f,%f)" %
                               (crat, crat,(1. - crat)*(cx + otx),
                                (1. - crat)*(cy - oty))),
#WHY Inkscape and SVG run +y in OPPOSITE directions is BEYOND me.
                "width" :  "100%",
                "height" : "100%",
                }
            parent.insert(j, inkex.etree.Element('use', att) )

# Create effect instance and apply it.
effect = clonesPerspectiveEffect()
effect.affect()
sys.exit( 0 )