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

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

"""
***************************************************************************
    SnapGeometries.py
    -----------------
    Date                 : October 2016
    Copyright            : (C) 2016 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__ = 'October 2016'
__copyright__ = '(C) 2016, Nyall Dawson'

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

__revision__ = '$Format:%H$'

from qgis.analysis import (QgsGeometrySnapper,
                           QgsInternalGeometrySnapper)
from qgis.core import (QgsFeatureSink,
                       QgsProcessing,
                       QgsProcessingParameterFeatureSource,
                       QgsProcessingParameterFeatureSink,
                       QgsProcessingParameterNumber,
                       QgsProcessingParameterEnum)

from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm


class SnapGeometriesToLayer(QgisAlgorithm):

    INPUT = 'INPUT'
    REFERENCE_LAYER = 'REFERENCE_LAYER'
    TOLERANCE = 'TOLERANCE'
    OUTPUT = 'OUTPUT'
    BEHAVIOR = 'BEHAVIOR'

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

    def __init__(self):
        super().__init__()

    def initAlgorithm(self, config=None):
        self.addParameter(QgsProcessingParameterFeatureSource(self.INPUT, self.tr('Input layer'), [QgsProcessing.TypeVectorPoint, QgsProcessing.TypeVectorLine, QgsProcessing.TypeVectorPolygon]))
        self.addParameter(QgsProcessingParameterFeatureSource(self.REFERENCE_LAYER, self.tr('Reference layer'),
                                                              [QgsProcessing.TypeVectorPoint,
                                                               QgsProcessing.TypeVectorLine,
                                                               QgsProcessing.TypeVectorPolygon]))

        self.addParameter(QgsProcessingParameterNumber(self.TOLERANCE, self.tr('Tolerance (layer units)'), type=QgsProcessingParameterNumber.Double,
                                                       minValue=0.00000001, maxValue=9999999999, defaultValue=10.0))

        self.modes = [self.tr('Prefer aligning nodes'),
                      self.tr('Prefer closest point'),
                      self.tr('Move end points only, prefer aligning nodes'),
                      self.tr('Move end points only, prefer closest point'),
                      self.tr('Snap end points to end points only')]
        self.addParameter(QgsProcessingParameterEnum(
            self.BEHAVIOR,
            self.tr('Behavior'),
            options=self.modes, defaultValue=0))

        self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT, self.tr('Snapped geometry')))

    def name(self):
        return 'snapgeometries'

    def displayName(self):
        return self.tr('Snap geometries to layer')

    def processAlgorithm(self, parameters, context, feedback):
        source = self.parameterAsSource(parameters, self.INPUT, context)

        reference_source = self.parameterAsSource(parameters, self.REFERENCE_LAYER, context)
        tolerance = self.parameterAsDouble(parameters, self.TOLERANCE, context)
        mode = self.parameterAsEnum(parameters, self.BEHAVIOR, context)

        (sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
                                               source.fields(), source.wkbType(), source.sourceCrs())

        features = source.getFeatures()
        total = 100.0 / source.featureCount() if source.featureCount() else 0

        if parameters[self.INPUT] != parameters[self.REFERENCE_LAYER]:
            snapper = QgsGeometrySnapper(reference_source)
            processed = 0
            for f in features:
                if feedback.isCanceled():
                    break
                if f.hasGeometry():
                    out_feature = f
                    out_feature.setGeometry(snapper.snapGeometry(f.geometry(), tolerance, mode))
                    sink.addFeature(out_feature, QgsFeatureSink.FastInsert)
                else:
                    sink.addFeature(f)
                processed += 1
                feedback.setProgress(processed * total)
        else:
            # snapping internally
            snapper = QgsInternalGeometrySnapper(tolerance, mode)
            processed = 0
            for f in features:
                if feedback.isCanceled():
                    break

                out_feature = f
                out_feature.setGeometry(snapper.snapFeature(f))
                sink.addFeature(out_feature, QgsFeatureSink.FastInsert)
                processed += 1
                feedback.setProgress(processed * total)

        return {self.OUTPUT: dest_id}