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 (QgsApplication,
                       QgsFeature,
                       QgsProcessingUtils)

from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.parameters import ParameterVector, ParameterNumber, ParameterSelection
from processing.core.outputs import OutputVector
from processing.tools import dataobjects, vector


class SnapGeometriesToLayer(GeoAlgorithm):

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

    def icon(self):
        return QgsApplication.getThemeIcon("/providerQgis.svg")

    def svgIconPath(self):
        return QgsApplication.iconPath("providerQgis.svg")

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

    def name(self):
        return 'snapgeometries'

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

    def defineCharacteristics(self):
        self.addParameter(ParameterVector(self.INPUT, self.tr('Input layer')))
        self.addParameter(ParameterVector(self.REFERENCE_LAYER, self.tr('Reference layer')))
        self.addParameter(ParameterNumber(self.TOLERANCE, self.tr('Tolerance (layer units)'), 0.00000001, 9999999999, default=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(ParameterSelection(
            self.BEHAVIOR,
            self.tr('Behavior'),
            self.modes, default=0))
        self.addOutput(OutputVector(self.OUTPUT, self.tr('Snapped geometries')))

    def processAlgorithm(self, context, feedback):
        layer = dataobjects.getLayerFromString(self.getParameterValue(self.INPUT))
        reference_layer = dataobjects.getLayerFromString(self.getParameterValue(self.REFERENCE_LAYER))
        tolerance = self.getParameterValue(self.TOLERANCE)
        mode = self.getParameterValue(self.BEHAVIOR)

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

        features = QgsProcessingUtils.getFeatures(layer, context)

        self.processed = 0
        self.feedback = feedback
        self.total = 100.0 / QgsProcessingUtils.featureCount(layer, context)

        if self.getParameterValue(self.INPUT) != self.getParameterValue(self.REFERENCE_LAYER):
            snapper = QgsGeometrySnapper(reference_layer)
            snapper.featureSnapped.connect(self.featureSnapped)
            snapped_features = snapper.snapFeatures(features, tolerance, mode)
            for f in snapped_features:
                writer.addFeature(QgsFeature(f))
        else:
            # snapping internally
            snapper = QgsInternalGeometrySnapper(tolerance, mode)
            processed = 0
            for f in features:
                out_feature = f
                out_feature.setGeometry(snapper.snapFeature(f))
                writer.addFeature(out_feature)
                processed += 1
                feedback.setProgress(processed * self.total)

        del writer

    def featureSnapped(self):
        self.processed += 1
        self.feedback.setProgress(int(self.processed * self.total))