QGIS » QGIS Application

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

from qgis.core import (QgsProcessing, QgsProcessingAlgorithm, QgsProcessingParameterFeatureSource, QgsGeometry, QgsMultiPoint)

class TestTriangulation(QgsProcessingAlgorithm):

    POINTS = 'POINTS'

    # OUTPUT = 'OUTPUT'

    def createInstance(self):

        return TestTriangulation()

    def name(self):

        return 'testtriangulation'

    def displayName(self):

        return 'Test Triangulation'

    def flags(self):

        return QgsProcessingAlgorithm.FlagNoThreading

    def group(self):

        return 'Test'

    def groupId(self):

        return 'test'

    def shortHelpString(self):

        return ''

    def initAlgorithm(self, config = None):

        self.addParameter(QgsProcessingParameterFeatureSource(self.POINTS, 'Points', [QgsProcessing.TypeVectorPoint]))

        # self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT, 'Triangles', QgsProcessing.TypeVectorPolygon))

    def processAlgorithm(self, parameters, context, feedback):

        pointLayer = self.parameterAsSource(parameters, self.POINTS, context)

        multiPoint = QgsMultiPoint()

        for pointFeature in pointLayer.getFeatures():

            multiPoint.addGeometry(pointFeature.geometry().vertexAt(0))

        multiPointGeometry = QgsGeometry(multiPoint)

        triangulation = multiPointGeometry.delaunayTriangulation(1e-3)

        multiTriangle = triangulation.get()

        # (sink, dest) = self.parameterAsSink(parameters, self.OUTPUT, context, QgsFields(), QgsWkbTypes.PolygonZ, context.project().crs())

        for i in range(multiTriangle.numGeometries()):

            triangle = multiTriangle.geometryN(i)

            triangleGeometry = QgsGeometry(triangle) # removing this line prevents the crash

            # feature = QgsFeature()

            # feature.setGeometry(triangleGeometry)

            # sink.addFeature(feature)

        return {} # {self.OUTPUT: dest}