QGIS/python/plugins/processing/algs/qgis/OrientedMinimumBoundingBox.py
Nyall Dawson 1e13d733c2 Move declaration of algorithm parameters/outputs to a new virtual
initAlgorithm() method

This allows 2 benefits:
- algorithms can be subclassed and have subclasses add additional
parameters/outputs to the algorithm. With the previous approach
of declaring parameters/outputs in the constructor, it's not
possible to call virtual methods to add additional parameters/
outputs (since you can't call virtual methods from a constructor).

- initAlgorithm takes a variant map argument, allowing the algorithm
to dynamically adjust its declared parameters and outputs according
to this configuration map. This potentially allows model algorithms which
can be configured to have variable numbers of parameters and
outputs at run time. E.g. a "router" algorithm which directs
features to one of any number of output sinks depending on some
user configured criteria.
2017-07-10 16:31:14 +10:00

145 lines
5.9 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
OrientedMinimumBoundingBox.py
---------------------
Date : June 2015
Copyright : (C) 2015, Loïc BARTOLETTI
Email : coder at tuxfamily dot org
***************************************************************************
* *
* 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__ = 'Loïc BARTOLETTI'
__date__ = 'June 2015'
__copyright__ = '(C) 2015, Loïc BARTOLETTI'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
from qgis.PyQt.QtCore import QVariant
from qgis.core import (QgsField,
QgsFields,
QgsFeatureSink,
QgsGeometry,
QgsFeature,
QgsWkbTypes,
QgsFeatureRequest,
QgsApplication,
QgsProcessingUtils)
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
from processing.core.parameters import ParameterVector
from processing.core.parameters import ParameterBoolean
from processing.core.outputs import OutputVector
from processing.tools import dataobjects
class OrientedMinimumBoundingBox(QgisAlgorithm):
INPUT_LAYER = 'INPUT_LAYER'
BY_FEATURE = 'BY_FEATURE'
OUTPUT = 'OUTPUT'
def group(self):
return self.tr('Vector general tools')
def __init__(self):
super().__init__()
def initAlgorithm(self, config=None):
self.addParameter(ParameterVector(self.INPUT_LAYER,
self.tr('Input layer')))
self.addParameter(ParameterBoolean(self.BY_FEATURE,
self.tr('Calculate OMBB for each feature separately'), True))
self.addOutput(OutputVector(self.OUTPUT, self.tr('Oriented_MBBox'), datatype=[dataobjects.TYPE_VECTOR_POLYGON]))
def name(self):
return 'orientedminimumboundingbox'
def displayName(self):
return self.tr('Oriented minimum bounding box')
def processAlgorithm(self, parameters, context, feedback):
layer = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.INPUT_LAYER), context)
byFeature = self.getParameterValue(self.BY_FEATURE)
if byFeature and layer.geometryType() == QgsWkbTypes.PointGeometry and layer.featureCount() <= 2:
raise GeoAlgorithmExecutionException(self.tr("Can't calculate an OMBB for each point, it's a point. The number of points must be greater than 2"))
if byFeature:
fields = layer.fields()
else:
fields = QgsFields()
fields.append(QgsField('area', QVariant.Double))
fields.append(QgsField('perimeter', QVariant.Double))
fields.append(QgsField('angle', QVariant.Double))
fields.append(QgsField('width', QVariant.Double))
fields.append(QgsField('height', QVariant.Double))
writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(fields, QgsWkbTypes.Polygon, layer.crs(), context)
if byFeature:
self.featureOmbb(layer, context, writer, feedback)
else:
self.layerOmmb(layer, context, writer, feedback)
del writer
def layerOmmb(self, layer, context, writer, feedback):
req = QgsFeatureRequest().setSubsetOfAttributes([])
features = QgsProcessingUtils.getFeatures(layer, context, req)
total = 100.0 / layer.featureCount() if layer.featureCount() else 0
newgeometry = QgsGeometry()
first = True
for current, inFeat in enumerate(features):
if first:
newgeometry = inFeat.geometry()
first = False
else:
newgeometry = newgeometry.combine(inFeat.geometry())
feedback.setProgress(int(current * total))
geometry, area, angle, width, height = newgeometry.orientedMinimumBoundingBox()
if geometry:
outFeat = QgsFeature()
outFeat.setGeometry(geometry)
outFeat.setAttributes([area,
width * 2 + height * 2,
angle,
width,
height])
writer.addFeature(outFeat, QgsFeatureSink.FastInsert)
def featureOmbb(self, layer, context, writer, feedback):
features = QgsProcessingUtils.getFeatures(layer, context)
total = 100.0 / layer.featureCount() if layer.featureCount() else 0
outFeat = QgsFeature()
for current, inFeat in enumerate(features):
geometry, area, angle, width, height = inFeat.geometry().orientedMinimumBoundingBox()
if geometry:
outFeat.setGeometry(geometry)
attrs = inFeat.attributes()
attrs.extend([area,
width * 2 + height * 2,
angle,
width,
height])
outFeat.setAttributes(attrs)
writer.addFeature(outFeat, QgsFeatureSink.FastInsert)
else:
feedback.pushInfo(self.tr("Can't calculate an OMBB for feature {0}.").format(inFeat.id()))
feedback.setProgress(int(current * total))