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2951afa324
Also allow feature based algorithms to customise their appectable input layers types and set suitable filters for all applicable algorithms
81 lines
2.9 KiB
Python
81 lines
2.9 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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ExtendLines.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 (QgsProcessingParameterNumber,
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QgsProcessingException,
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QgsProcessing)
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from processing.algs.qgis.QgisAlgorithm import QgisFeatureBasedAlgorithm
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class ExtendLines(QgisFeatureBasedAlgorithm):
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START_DISTANCE = 'START_DISTANCE'
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END_DISTANCE = 'END_DISTANCE'
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def group(self):
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return self.tr('Vector geometry')
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def __init__(self):
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super().__init__()
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self.start_distance = None
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self.end_distance = None
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def initParameters(self, config=None):
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self.addParameter(QgsProcessingParameterNumber(self.START_DISTANCE,
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self.tr('Start distance'), defaultValue=0.0))
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self.addParameter(QgsProcessingParameterNumber(self.END_DISTANCE,
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self.tr('End distance'), defaultValue=0.0))
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def name(self):
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return 'extendlines'
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def displayName(self):
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return self.tr('Extend lines')
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def outputName(self):
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return self.tr('Extended')
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def inputLayerTypes(self):
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return [QgsProcessing.TypeVectorLine]
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def prepareAlgorithm(self, parameters, context, feedback):
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self.start_distance = self.parameterAsDouble(parameters, self.START_DISTANCE, context)
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self.end_distance = self.parameterAsDouble(parameters, self.END_DISTANCE, context)
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return True
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def processFeature(self, feature, feedback):
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input_geometry = feature.geometry()
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if input_geometry:
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output_geometry = input_geometry.extendLine(self.start_distance, self.end_distance)
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if not output_geometry:
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raise QgsProcessingException(
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self.tr('Error calculating extended line'))
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feature.setGeometry(output_geometry)
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return feature
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