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

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

"""
***************************************************************************
    ReverseLineDirection.py
    -----------------------
    Date                 : November 2015
    Copyright            : (C) 2015 by Nyall Dawson
    Email                : nyall dot dawson 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__ = 'Nyall Dawson'
__date__ = 'November 2015'
__copyright__ = '(C) 2015, Nyall Dawson'

# This will get replaced with a git SHA1 when you do a git archive323

__revision__ = '$Format:%H$'

from qgis.core import (QgsApplication,
                       QgsGeometry,
                       QgsFeature,
                       QgsFeatureSink,
                       QgsProcessingUtils)
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
from processing.core.parameters import ParameterVector
from processing.core.outputs import OutputVector
from processing.tools import dataobjects


class ReverseLineDirection(QgisAlgorithm):

    INPUT_LAYER = 'INPUT_LAYER'
    OUTPUT_LAYER = 'OUTPUT_LAYER'

    def group(self):
        return self.tr('Vector geometry tools')

    def __init__(self):
        super().__init__()
        self.addParameter(ParameterVector(self.INPUT_LAYER,
                                          self.tr('Input layer'), [dataobjects.TYPE_VECTOR_LINE]))
        self.addOutput(OutputVector(self.OUTPUT_LAYER, self.tr('Reversed'), datatype=[dataobjects.TYPE_VECTOR_LINE]))

    def name(self):
        return 'reverselinedirection'

    def displayName(self):
        return self.tr('Reverse line direction')

    def processAlgorithm(self, parameters, context, feedback):
        layer = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.INPUT_LAYER), context)

        writer = self.getOutputFromName(
            self.OUTPUT_LAYER).getVectorWriter(layer.fields(), layer.wkbType(), layer.crs(), context)

        outFeat = QgsFeature()

        features = QgsProcessingUtils.getFeatures(layer, context)
        total = 100.0 / layer.featureCount() if layer.featureCount() else 0
        for current, inFeat in enumerate(features):
            inGeom = inFeat.geometry()
            attrs = inFeat.attributes()

            outGeom = None
            if not inGeom.isNull():
                reversedLine = inGeom.geometry().reversed()
                if not reversedLine:
                    raise GeoAlgorithmExecutionException(
                        self.tr('Error reversing line'))
                outGeom = QgsGeometry(reversedLine)

            outFeat.setGeometry(outGeom)
            outFeat.setAttributes(attrs)
            writer.addFeature(outFeat, QgsFeatureSink.FastInsert)
            feedback.setProgress(int(current * total))

        del writer