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134 lines
5.2 KiB
Python
134 lines
5.2 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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GeometryByExpression.py
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-----------------------
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Date : October 2016
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Copyright : (C) 2016 by Nyall Dawson
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Email : nyall dot dawson at gmail dot com
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***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************
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"""
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__author__ = 'Nyall Dawson'
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__date__ = 'October 2016'
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__copyright__ = '(C) 2016, Nyall Dawson'
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# This will get replaced with a git SHA1 when you do a git archive323
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__revision__ = '$Format:%H$'
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from qgis.core import (QgsWkbTypes,
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QgsExpression,
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QgsGeometry,
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QgsProcessing,
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QgsProcessingAlgorithm,
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QgsProcessingException,
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QgsProcessingParameterBoolean,
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QgsProcessingParameterEnum,
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QgsProcessingParameterExpression,
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QgsProcessingFeatureSource)
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from processing.algs.qgis.QgisAlgorithm import QgisFeatureBasedAlgorithm
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class GeometryByExpression(QgisFeatureBasedAlgorithm):
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OUTPUT_GEOMETRY = 'OUTPUT_GEOMETRY'
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WITH_Z = 'WITH_Z'
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WITH_M = 'WITH_M'
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EXPRESSION = 'EXPRESSION'
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def group(self):
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return self.tr('Vector geometry')
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def groupId(self):
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return 'vectorgeometry'
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def flags(self):
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return super().flags() & ~QgsProcessingAlgorithm.FlagSupportsInPlaceEdits
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def __init__(self):
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super().__init__()
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self.geometry_types = [self.tr('Polygon'),
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'Line',
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'Point']
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def initParameters(self, config=None):
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self.addParameter(QgsProcessingParameterEnum(
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self.OUTPUT_GEOMETRY,
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self.tr('Output geometry type'),
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options=self.geometry_types, defaultValue=0))
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self.addParameter(QgsProcessingParameterBoolean(self.WITH_Z,
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self.tr('Output geometry has z dimension'), defaultValue=False))
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self.addParameter(QgsProcessingParameterBoolean(self.WITH_M,
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self.tr('Output geometry has m values'), defaultValue=False))
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self.addParameter(QgsProcessingParameterExpression(self.EXPRESSION,
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self.tr("Geometry expression"), defaultValue='$geometry', parentLayerParameterName='INPUT'))
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def name(self):
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return 'geometrybyexpression'
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def displayName(self):
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return self.tr('Geometry by expression')
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def outputName(self):
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return self.tr('Modified geometry')
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def prepareAlgorithm(self, parameters, context, feedback):
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self.geometry_type = self.parameterAsEnum(parameters, self.OUTPUT_GEOMETRY, context)
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self.wkb_type = None
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if self.geometry_type == 0:
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self.wkb_type = QgsWkbTypes.Polygon
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elif self.geometry_type == 1:
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self.wkb_type = QgsWkbTypes.LineString
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else:
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self.wkb_type = QgsWkbTypes.Point
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if self.parameterAsBool(parameters, self.WITH_Z, context):
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self.wkb_type = QgsWkbTypes.addZ(self.wkb_type)
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if self.parameterAsBool(parameters, self.WITH_M, context):
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self.wkb_type = QgsWkbTypes.addM(self.wkb_type)
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self.expression = QgsExpression(self.parameterAsString(parameters, self.EXPRESSION, context))
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if self.expression.hasParserError():
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feedback.reportError(self.expression.parserErrorString())
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return False
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self.expression_context = self.createExpressionContext(parameters, context)
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self.expression.prepare(self.expression_context)
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return True
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def outputWkbType(self, input_wkb_type):
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return self.wkb_type
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def inputLayerTypes(self):
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return [QgsProcessing.TypeVector]
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def sourceFlags(self):
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return QgsProcessingFeatureSource.FlagSkipGeometryValidityChecks
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def processFeature(self, feature, context, feedback):
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self.expression_context.setFeature(feature)
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value = self.expression.evaluate(self.expression_context)
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if self.expression.hasEvalError():
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raise QgsProcessingException(
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self.tr('Evaluation error: {0}').format(self.expression.evalErrorString()))
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if not value:
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feature.setGeometry(QgsGeometry())
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else:
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if not isinstance(value, QgsGeometry):
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raise QgsProcessingException(
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self.tr('{} is not a geometry').format(value))
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feature.setGeometry(value)
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return [feature]
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