root/branch/joao/umitMapper/Interpolation.py @ 622

# Copyright (C) 2007 Adriano Monteiro Marques <py.adriano@gmail.com>
#
# Author: Joao Paulo de Souza Medeiros <ignotus21@gmail.com>
#
# 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

from Numeric import arange


class Linear2DInterpolator:
    """
    Implements a bidimesional linear interpolator.
    """

    def __init__(self):
        """
        Constructor method of Linear2DInterpolator class
        """
        self.__initialPoint = (0, 0)
        """Initial point of interpolation"""
        self.__finalPoint = (0, 0)
        """Final point of interpolation"""
        self.__interpolatedPoints = []
        """Interpolated points vector"""


    def setInitialPoint(self, a, b):
        """
        Set initial coordinate
        Set final coordinate
        @type  a: number
        @param a: The first component of final point
        @type  b: number
        @param b: The second component of final point
        """
        self.__initialPoint = (a, b)


    def setFinalPoint(self, a, b):
        """
        Set final coordinate
        @type  a: number
        @param a: The first component of final point
        @type  b: number
        @param b: The second component of final point
        """
        self.__finalPoint = (a, b)


    def interpolate(self, a):
        """
        Return the primary point with the interpolated point
        @type  a: number
        @param a: The first component of point to be interpolated
        @rtype: tuple
        @return: Tuple with interpolated points
        """
        (ai, bi) = self.__initialPoint
        (af, bf) = self.__finalPoint

        try:
            result = (a, bi + ((a - ai) * (bf - bi) / (af - ai)))
        except ZeroDivisionError:
            result = (a, bf)

        return result


    def getInterpolatedPoints(self, numberOfPass):
        """
        Return the vector of coordinates between the initial and final
        coordinates with the specified size
        @type  numberOfPass: number
        @param numberOfPass: The number of pass of interpolation
        @rtype: list
        @return: A list of tuples with interpolated points
        """
        (ai, bi) = self.__initialPoint
        (af, bf) = self.__finalPoint

        aPass = float(af - ai) / numberOfPass

        self.__interpolatedPoints = range(numberOfPass)

        for i in range(numberOfPass):
            self.__interpolatedPoints[i] = self.interpolate(ai + (i + 1) * aPass)

        return self.__interpolatedPoints



if __name__ == "__main__":

    # Testing application

    i = Linear2DInterpolator()
    i.setInitialPoint(0, 0)
    i.setFinalPoint(1, 1)
    print len(i.getInterpolatedPoints(10)), i.getInterpolatedPoints(10)