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

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

"""
***************************************************************************
    ExtractNodes.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 qgis.core import QGis, QgsFeature, QgsGeometry
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.parameters import ParameterVector
from processing.core.outputs import OutputVector
from processing.tools import dataobjects, vector


class ExtractNodes(GeoAlgorithm):

    INPUT = 'INPUT'
    OUTPUT = 'OUTPUT'

    def defineCharacteristics(self):
        self.name, self.i18n_name = self.trAlgorithm('Extract nodes')
        self.group, self.i18n_group = self.trAlgorithm('Vector geometry tools')

        self.addParameter(ParameterVector(self.INPUT,
                                          self.tr('Input layer'),
                                          [ParameterVector.VECTOR_TYPE_POLYGON, ParameterVector.VECTOR_TYPE_LINE]))

        self.addOutput(OutputVector(self.OUTPUT, self.tr('Nodes')))

    def processAlgorithm(self, progress):
        layer = dataobjects.getObjectFromUri(
            self.getParameterValue(self.INPUT))

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

        outFeat = QgsFeature()
        inGeom = QgsGeometry()
        outGeom = QgsGeometry()

        current = 0
        features = vector.features(layer)
        total = 100.0 / float(len(features))
        for f in features:
            inGeom = f.geometry()
            attrs = f.attributes()

            points = vector.extractPoints(inGeom)
            outFeat.setAttributes(attrs)

            for i in points:
                outFeat.setGeometry(outGeom.fromPoint(i))
                writer.addFeature(outFeat)

            current += 1
            progress.setPercentage(int(current * total))

        del writer