QGIS/python/plugins/processing/algs/qgis/FixedDistanceBuffer.py

# -*- coding: utf-8 -*-

"""
***************************************************************************
    FixedDistanceBuffer.py
    ---------------------
    Date                 : August 2012
    Copyright            : (C) 2012 by Victor Olaya
    Email                : volayaf at gmail dot 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.                                   *
*                                                                         *
***************************************************************************
"""

__author__ = 'Victor Olaya'
__date__ = 'August 2012'
__copyright__ = '(C) 2012, Victor Olaya'

# This will get replaced with a git SHA1 when you do a git archive

__revision__ = '$Format:%H$'

from PyQt4.QtCore import *
from qgis.core import *
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.parameters import ParameterVector
from processing.core.parameters import ParameterBoolean
from processing.core.parameters import ParameterNumber
from processing.core.outputs import OutputVector
import Buffer as buff
from processing.tools import dataobjects


class FixedDistanceBuffer(GeoAlgorithm):

    INPUT = 'INPUT'
    OUTPUT = 'OUTPUT'
    FIELD = 'FIELD'
    DISTANCE = 'DISTANCE'
    SEGMENTS = 'SEGMENTS'
    DISSOLVE = 'DISSOLVE'

    # =========================================================================
    # def getIcon(self):
    #    return QtGui.QIcon(os.path.dirname(__file__) + "/icons/buffer.png")
    # =========================================================================

    def defineCharacteristics(self):
        self.name = 'Fixed distance buffer'
        self.group = 'Vector geometry tools'
        self.addParameter(ParameterVector(self.INPUT, 'Input layer',
                          [ParameterVector.VECTOR_TYPE_ANY]))
        self.addParameter(ParameterNumber(self.DISTANCE, 'Distance',
                          default=10.0))
        self.addParameter(ParameterNumber(self.SEGMENTS, 'Segments', 1,
                          default=5))
        self.addParameter(ParameterBoolean(self.DISSOLVE, 'Dissolve result',
                          False))

        self.addOutput(OutputVector(self.OUTPUT, 'Buffer'))

    def processAlgorithm(self, progress):
        layer = dataobjects.getObjectFromUri(
                self.getParameterValue(self.INPUT))
        distance = self.getParameterValue(self.DISTANCE)
        dissolve = self.getParameterValue(self.DISSOLVE)
        segments = int(self.getParameterValue(self.SEGMENTS))

        writer = self.getOutputFromName(
                self.OUTPUT).getVectorWriter(layer.pendingFields().toList(),
                                             QGis.WKBPolygon, layer.crs())

        buff.buffering(progress, writer, distance, None, False, layer,
                       dissolve, segments)