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

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

"""
***************************************************************************
    Delaunay.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__ = '$Format:%H$'

import os

from qgis.PyQt.QtGui import QIcon
from qgis.PyQt.QtCore import QVariant

from qgis.core import (QgsApplication,
                       QgsField,
                       QgsFeatureRequest,
                       QgsFeatureSink,
                       QgsFeature,
                       QgsGeometry,
                       QgsPointXY,
                       QgsWkbTypes,
                       QgsProcessing,
                       QgsFields,
                       QgsProcessingException,
                       QgsProcessingParameterFeatureSource,
                       QgsProcessingParameterFeatureSink)

from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm

from . import voronoi

pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]


class Delaunay(QgisAlgorithm):

    INPUT = 'INPUT'
    OUTPUT = 'OUTPUT'

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

    def svgIconPath(self):
        return QgsApplication.iconPath("/algorithms/mAlgorithmDelaunay.svg")

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

    def groupId(self):
        return 'vectorgeometry'

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

    def initAlgorithm(self, config=None):
        self.addParameter(QgsProcessingParameterFeatureSource(self.INPUT, self.tr('Input layer'), [QgsProcessing.TypeVectorPoint]))
        self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT, self.tr('Delaunay triangulation'), type=QgsProcessing.TypeVectorPolygon))

    def name(self):
        return 'delaunaytriangulation'

    def displayName(self):
        return self.tr('Delaunay triangulation')

    def processAlgorithm(self, parameters, context, feedback):
        source = self.parameterAsSource(parameters, self.INPUT, context)
        if source is None:
            raise QgsProcessingException(self.invalidSourceError(parameters, self.INPUT))

        fields = QgsFields()
        fields.append(QgsField('POINTA', QVariant.Double, '', 24, 15))
        fields.append(QgsField('POINTB', QVariant.Double, '', 24, 15))
        fields.append(QgsField('POINTC', QVariant.Double, '', 24, 15))

        (sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
                                               fields, QgsWkbTypes.Polygon, source.sourceCrs())
        if sink is None:
            raise QgsProcessingException(self.invalidSinkError(parameters, self.OUTPUT))

        pts = []
        ptDict = {}
        ptNdx = -1
        c = voronoi.Context()
        features = source.getFeatures()
        total = 100.0 / source.featureCount() if source.featureCount() else 0
        for current, inFeat in enumerate(features):
            if feedback.isCanceled():
                break

            geom = QgsGeometry(inFeat.geometry())
            if geom.isNull():
                continue
            if geom.isMultipart():
                points = geom.asMultiPoint()
            else:
                points = [geom.asPoint()]
            for n, point in enumerate(points):
                x = point.x()
                y = point.y()
                pts.append((x, y))
                ptNdx += 1
                ptDict[ptNdx] = (inFeat.id(), n)
            feedback.setProgress(int(current * total))

        if len(pts) < 3:
            raise QgsProcessingException(
                self.tr('Input file should contain at least 3 points. Choose '
                        'another file and try again.'))

        uniqueSet = set(item for item in pts)
        ids = [pts.index(item) for item in uniqueSet]
        sl = voronoi.SiteList([voronoi.Site(*i) for i in uniqueSet])
        c.triangulate = True
        voronoi.voronoi(sl, c)
        triangles = c.triangles
        feat = QgsFeature()

        total = 100.0 / len(triangles) if triangles else 1
        for current, triangle in enumerate(triangles):
            if feedback.isCanceled():
                break

            indices = list(triangle)
            indices.append(indices[0])
            polygon = []
            attrs = []
            step = 0
            for index in indices:
                fid, n = ptDict[ids[index]]
                request = QgsFeatureRequest().setFilterFid(fid)
                inFeat = next(source.getFeatures(request))
                geom = QgsGeometry(inFeat.geometry())
                if geom.isMultipart():
                    point = QgsPointXY(geom.asMultiPoint()[n])
                else:
                    point = QgsPointXY(geom.asPoint())
                polygon.append(point)
                if step <= 3:
                    attrs.append(ids[index])
                step += 1
            feat.setAttributes(attrs)
            geometry = QgsGeometry().fromPolygonXY([polygon])
            feat.setGeometry(geometry)
            sink.addFeature(feat, QgsFeatureSink.FastInsert)
            feedback.setProgress(int(current * total))

        return {self.OUTPUT: dest_id}