QGIS/python/plugins/processing/algs/qgis/PointsDisplacement.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

136 lines
5.2 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
PointsDisplacement.py
---------------------
Date : July 2013
Copyright : (C) 2013 by Alexander Bruy
Email : alexander dot bruy 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. *
* *
***************************************************************************
"""
from builtins import next
__author__ = 'Alexander Bruy'
__date__ = 'July 2013'
__copyright__ = '(C) 2013, Alexander Bruy'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
import math
from qgis.core import (QgsApplication,
QgsFeatureRequest,
QgsFeature,
QgsFeatureSink,
QgsGeometry,
QgsPointXY,
QgsProcessingUtils)
from processing.tools import dataobjects
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
from processing.core.parameters import ParameterVector
from processing.core.parameters import ParameterNumber
from processing.core.parameters import ParameterBoolean
from processing.core.outputs import OutputVector
class PointsDisplacement(QgisAlgorithm):
INPUT_LAYER = 'INPUT_LAYER'
DISTANCE = 'DISTANCE'
HORIZONTAL = 'HORIZONTAL'
OUTPUT_LAYER = 'OUTPUT_LAYER'
def group(self):
return self.tr('Vector geometry tools')
def __init__(self):
super().__init__()
def initAlgorithm(self, config=None):
self.addParameter(ParameterVector(self.INPUT_LAYER,
self.tr('Input layer'), [dataobjects.TYPE_VECTOR_POINT]))
self.addParameter(ParameterNumber(self.DISTANCE,
self.tr('Displacement distance'),
0.00001, 999999999.999990, 0.00015))
self.addParameter(ParameterBoolean(self.HORIZONTAL,
self.tr('Horizontal distribution for two point case')))
self.addOutput(OutputVector(self.OUTPUT_LAYER, self.tr('Displaced'), datatype=[dataobjects.TYPE_VECTOR_POINT]))
def name(self):
return 'pointsdisplacement'
def displayName(self):
return self.tr('Points displacement')
def processAlgorithm(self, parameters, context, feedback):
radius = self.getParameterValue(self.DISTANCE)
horizontal = self.getParameterValue(self.HORIZONTAL)
output = self.getOutputFromName(self.OUTPUT_LAYER)
layer = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.INPUT_LAYER), context)
writer = output.getVectorWriter(layer.fields(), layer.wkbType(), layer.crs(), context)
features = QgsProcessingUtils.getFeatures(layer, context)
total = 100.0 / layer.featureCount() if layer.featureCount() else 0
duplicates = dict()
for current, f in enumerate(features):
wkt = f.geometry().exportToWkt()
if wkt not in duplicates:
duplicates[wkt] = [f.id()]
else:
duplicates[wkt].extend([f.id()])
feedback.setProgress(int(current * total))
current = 0
total = 100.0 / len(duplicates) if duplicates else 1
feedback.setProgress(0)
fullPerimeter = 2 * math.pi
for (geom, fids) in list(duplicates.items()):
count = len(fids)
if count == 1:
f = next(layer.getFeatures(QgsFeatureRequest().setFilterFid(fids[0])))
writer.addFeature(f, QgsFeatureSink.FastInsert)
else:
angleStep = fullPerimeter / count
if count == 2 and horizontal:
currentAngle = math.pi / 2
else:
currentAngle = 0
old_point = QgsGeometry.fromWkt(geom).asPoint()
request = QgsFeatureRequest().setFilterFids(fids).setFlags(QgsFeatureRequest.NoGeometry)
for f in layer.getFeatures(request):
sinusCurrentAngle = math.sin(currentAngle)
cosinusCurrentAngle = math.cos(currentAngle)
dx = radius * sinusCurrentAngle
dy = radius * cosinusCurrentAngle
new_point = QgsPointXY(old_point.x() + dx, old_point.y() + dy)
out_feature = QgsFeature()
out_feature.setGeometry(QgsGeometry.fromPoint(new_point))
out_feature.setAttributes(f.attributes())
writer.addFeature(out_feature, QgsFeatureSink.FastInsert)
currentAngle += angleStep
current += 1
feedback.setProgress(int(current * total))
del writer