Nyall Dawson fd2c18ee16 Refactor processing writer to use QgsFeatureSink, and to store
temporary output layers in the provided processing context

Should fix loss of intermediate memory layers when running
a multi-step model
2017-04-26 17:38:40 +10:00

109 lines
4.1 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
Difference.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.core import (QgsFeatureRequest,
QgsFeature,
QgsGeometry,
QgsWkbTypes,
QgsMessageLog,
QgsProcessingUtils)
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.parameters import ParameterVector
from processing.core.outputs import OutputVector
from processing.tools import dataobjects, vector
pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
class Difference(GeoAlgorithm):
INPUT = 'INPUT'
OVERLAY = 'OVERLAY'
IGNORE_INVALID = 'IGNORE_INVALID'
OUTPUT = 'OUTPUT'
def icon(self):
return QIcon(os.path.join(pluginPath, 'images', 'ftools', 'difference.png'))
def group(self):
return self.tr('Vector overlay tools')
def name(self):
return 'difference'
def displayName(self):
return self.tr('Difference')
def defineCharacteristics(self):
self.addParameter(ParameterVector(Difference.INPUT,
self.tr('Input layer')))
self.addParameter(ParameterVector(Difference.OVERLAY,
self.tr('Difference layer')))
self.addOutput(OutputVector(Difference.OUTPUT, self.tr('Difference')))
def processAlgorithm(self, context, feedback):
layerA = dataobjects.getLayerFromString(
self.getParameterValue(Difference.INPUT))
layerB = dataobjects.getLayerFromString(
self.getParameterValue(Difference.OVERLAY))
geomType = QgsWkbTypes.multiType(layerA.wkbType())
writer = self.getOutputFromName(
Difference.OUTPUT).getVectorWriter(layerA.fields(), geomType, layerA.crs(), context)
outFeat = QgsFeature()
index = vector.spatialindex(layerB)
selectionA = QgsProcessingUtils.getFeatures(layerA, context)
total = 100.0 / QgsProcessingUtils.featureCount(layerA, context)
for current, inFeatA in enumerate(selectionA):
geom = inFeatA.geometry()
diff_geom = QgsGeometry(geom)
attrs = inFeatA.attributes()
intersections = index.intersects(geom.boundingBox())
request = QgsFeatureRequest().setFilterFids(intersections).setSubsetOfAttributes([])
for inFeatB in layerB.getFeatures(request):
tmpGeom = inFeatB.geometry()
if diff_geom.intersects(tmpGeom):
diff_geom = QgsGeometry(diff_geom.difference(tmpGeom))
try:
outFeat.setGeometry(diff_geom)
outFeat.setAttributes(attrs)
writer.addFeature(outFeat)
except:
QgsMessageLog.logMessage(self.tr('Feature geometry error: One or more output features ignored due to invalid geometry.'), self.tr('Processing'), QgsMessageLog.WARNING)
continue
feedback.setProgress(int(current * total))
del writer