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b1cadb1822
have specific icons, instead of generic qgis icon We consider these 'top level' algorithms, and using the standard algorithm icon should help reflect this and differentiate them from 3rd party algorithms.
135 lines
5.4 KiB
Python
135 lines
5.4 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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QgsFeatureSink,
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QgsExpressionContext,
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QgsExpressionContextUtils,
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QgsGeometry,
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QgsApplication,
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QgsProcessingUtils)
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from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
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from processing.core.parameters import ParameterVector, ParameterSelection, ParameterBoolean, ParameterExpression
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from processing.core.outputs import OutputVector
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class GeometryByExpression(QgisAlgorithm):
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INPUT_LAYER = 'INPUT_LAYER'
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OUTPUT_LAYER = 'OUTPUT_LAYER'
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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 tools')
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def __init__(self):
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super().__init__()
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self.addParameter(ParameterVector(self.INPUT_LAYER,
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self.tr('Input layer')))
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self.geometry_types = [self.tr('Polygon'),
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'Line',
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'Point']
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self.addParameter(ParameterSelection(
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self.OUTPUT_GEOMETRY,
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self.tr('Output geometry type'),
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self.geometry_types, default=0))
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self.addParameter(ParameterBoolean(self.WITH_Z,
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self.tr('Output geometry has z dimension'), False))
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self.addParameter(ParameterBoolean(self.WITH_M,
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self.tr('Output geometry has m values'), False))
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self.addParameter(ParameterExpression(self.EXPRESSION,
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self.tr("Geometry expression"), '$geometry', parent_layer=self.INPUT_LAYER))
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self.addOutput(OutputVector(self.OUTPUT_LAYER, self.tr('Modified geometry')))
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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 processAlgorithm(self, parameters, context, feedback):
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layer = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.INPUT_LAYER), context)
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geometry_type = self.getParameterValue(self.OUTPUT_GEOMETRY)
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wkb_type = None
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if geometry_type == 0:
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wkb_type = QgsWkbTypes.Polygon
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elif geometry_type == 1:
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wkb_type = QgsWkbTypes.LineString
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else:
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wkb_type = QgsWkbTypes.Point
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if self.getParameterValue(self.WITH_Z):
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wkb_type = QgsWkbTypes.addZ(wkb_type)
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if self.getParameterValue(self.WITH_M):
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wkb_type = QgsWkbTypes.addM(wkb_type)
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writer = self.getOutputFromName(
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self.OUTPUT_LAYER).getVectorWriter(layer.fields(), wkb_type, layer.crs(), context)
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expression = QgsExpression(self.getParameterValue(self.EXPRESSION))
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if expression.hasParserError():
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raise GeoAlgorithmExecutionException(expression.parserErrorString())
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exp_context = QgsExpressionContext(QgsExpressionContextUtils.globalProjectLayerScopes(layer))
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if not expression.prepare(exp_context):
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raise GeoAlgorithmExecutionException(
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self.tr('Evaluation error: {0}').format(expression.evalErrorString()))
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features = QgsProcessingUtils.getFeatures(layer, context)
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total = 100.0 / layer.featureCount() if layer.featureCount() else 0
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for current, input_feature in enumerate(features):
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output_feature = input_feature
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exp_context.setFeature(input_feature)
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value = expression.evaluate(exp_context)
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if expression.hasEvalError():
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raise GeoAlgorithmExecutionException(
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self.tr('Evaluation error: {0}').format(expression.evalErrorString()))
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if not value:
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output_feature.setGeometry(QgsGeometry())
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else:
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if not isinstance(value, QgsGeometry):
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raise GeoAlgorithmExecutionException(
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self.tr('{} is not a geometry').format(value))
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output_feature.setGeometry(value)
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writer.addFeature(output_feature, QgsFeatureSink.FastInsert)
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feedback.setProgress(int(current * total))
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del writer
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