createRose.py

"""
/***************************************************************************
 *                                                                         *
 *   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.                                   *
 *                                                                         *
 ***************************************************************************/
"""
import os
import math
from geographiclib.geodesic import Geodesic

from qgis.core import (
    QgsPointXY, QgsGeometry, QgsField,
    QgsProject, QgsWkbTypes, QgsCoordinateTransform)

from qgis.core import (
    QgsProcessing,
    QgsProcessingFeatureBasedAlgorithm,
    QgsProcessingParameterBoolean,
    QgsProcessingParameterNumber,
    QgsProcessingParameterEnum)

from qgis.PyQt.QtGui import QIcon
from qgis.PyQt.QtCore import QVariant, QUrl

from .settings import settings, epsg4326, geod
from .utils import tr, conversionToMeters, makeIdlCrossingsPositive, DISTANCE_LABELS
import traceback

SHAPE_TYPE = [tr("Polygon"), tr("Line")]


class CreateRoseAlgorithm(QgsProcessingFeatureBasedAlgorithm):
    """
    Algorithm to create a donut shape.
    """

    PrmShapeType = 'ShapeType'
    PrmPetals = 'Petals'
    PrmRadius = 'Radius'
    PrmStartingAngle = 'StartingAngle'
    PrmUnitsOfMeasure = 'UnitsOfMeasure'
    PrmExportInputGeometry = 'ExportInputGeometry'

    def createInstance(self):
        return CreateRoseAlgorithm()

    def name(self):
        return 'createrose'

    def icon(self):
        return QIcon(os.path.join(os.path.dirname(__file__), 'images/rose.png'))

    def displayName(self):
        return tr('Create ellipse rose')

    def group(self):
        return tr('Geodesic shapes')

    def groupId(self):
        return 'vectorcreation'

    def outputName(self):
        return tr('Output layer')

    def helpUrl(self):
        file = os.path.dirname(__file__) + '/index.html'
        if not os.path.exists(file):
            return ''
        return QUrl.fromLocalFile(file).toString(QUrl.FullyEncoded)

    def inputLayerTypes(self):
        return [QgsProcessing.TypeVectorPoint]

    def outputWkbType(self, input_wkb_type):
        if self.shape_type == 0:
            return (QgsWkbTypes.Polygon)
        return (QgsWkbTypes.LineString)

    def outputFields(self, input_fields):
        if self.export_geom:
            name_x, name_y = settings.getGeomNames(input_fields.names())
            input_fields.append(QgsField(name_x, QVariant.Double))
            input_fields.append(QgsField(name_y, QVariant.Double))
        return(input_fields)

    def  supportInPlaceEdit(self, layer):
        return False

    def initParameters(self, config=None):
        self.shape_type = 0
        self.export_geom = False
        self.addParameter(
            QgsProcessingParameterEnum(
                self.PrmShapeType,
                tr('Shape type'),
                options=SHAPE_TYPE,
                defaultValue=0,
                optional=False)
        )
        self.addParameter(
            QgsProcessingParameterNumber(
                self.PrmPetals,
                tr('Number of petals'),
                QgsProcessingParameterNumber.Integer,
                defaultValue=8,
                minValue=1,
                optional=False)
        )
        self.addParameter(
            QgsProcessingParameterNumber(
                self.PrmStartingAngle,
                tr('Starting angle'),
                QgsProcessingParameterNumber.Double,
                defaultValue=0,
                optional=False)
        )
        self.addParameter(
            QgsProcessingParameterNumber(
                self.PrmRadius,
                tr('Radius'),
                QgsProcessingParameterNumber.Double,
                defaultValue=40.0,
                minValue=0,
                optional=False)
        )
        self.addParameter(
            QgsProcessingParameterEnum(
                self.PrmUnitsOfMeasure,
                tr('Radius units of measure'),
                options=DISTANCE_LABELS,
                defaultValue=0,
                optional=False)
        )
        self.addParameter(
            QgsProcessingParameterBoolean(
                self.PrmExportInputGeometry,
                tr('Add input geometry fields to output table'),
                False,
                optional=True)
        )

    def prepareAlgorithm(self, parameters, context, feedback):
        self.shape_type = self.parameterAsInt(parameters, self.PrmShapeType, context)
        self.radius = self.parameterAsDouble(parameters, self.PrmRadius, context)
        self.startAngle = self.parameterAsDouble(parameters, self.PrmStartingAngle, context)
        self.petals = self.parameterAsInt(parameters, self.PrmPetals, context)
        units = self.parameterAsInt(parameters, self.PrmUnitsOfMeasure, context)
        self.export_geom = self.parameterAsBool(parameters, self.PrmExportInputGeometry, context)

        measureFactor = conversionToMeters(units)
        self.radius *= measureFactor

        # Calculate distances one time.
        self.dist = []
        if self.petals == 1:
            self.dist.append(0.0)
        step = 1
        angle = -90.0 + step
        while angle < 90.0:
            a = math.radians(angle)
            r = math.cos(a)
            self.dist.append(r)
            angle += step
        self.dist_cnt = len(self.dist)

        source = self.parameterAsSource(parameters, 'INPUT', context)
        srcCRS = source.sourceCrs()
        self.total_features = source.featureCount()

        if srcCRS != epsg4326:
            self.geomTo4326 = QgsCoordinateTransform(srcCRS, epsg4326, QgsProject.instance())
            self.toSinkCrs = QgsCoordinateTransform(epsg4326, srcCRS, QgsProject.instance())
        else:
            self.geomTo4326 = None
            self.toSinkCrs = None
        self.num_bad = 0
        return True

    def processFeature(self, feature, context, feedback):
        try:
            pts = []
            pt = feature.geometry().asPoint()
            pt_orig_x = pt.x()
            pt_orig_y = pt.y()
            # make sure the coordinates are in EPSG:4326
            if self.geomTo4326:
                pt = self.geomTo4326.transform(pt.x(), pt.y())
            arange = 360.0 / self.petals
            angle = -arange / 2.0
            astep = arange / self.dist_cnt
            for i in range(self.petals):
                aoffset = arange * (self.petals - 1)
                index = 0
                while index < self.dist_cnt:
                    r = self.dist[index] * self.radius
                    g = geod.Direct(pt.y(), pt.x(), angle + aoffset + self.startAngle, r, Geodesic.LATITUDE | Geodesic.LONGITUDE)
                    pts.append(QgsPointXY(g['lon2'], g['lat2']))
                    angle += astep
                    index += 1
            # repeat the very first point to close the polygon
            pts.append(pts[0])

            makeIdlCrossingsPositive(pts)
            # If the Output crs is not 4326 transform the points to the proper crs
            if self.toSinkCrs:
                for x, ptout in enumerate(pts):
                    pts[x] = self.toSinkCrs.transform(ptout)

            if self.shape_type == 0:
                feature.setGeometry(QgsGeometry.fromPolygonXY([pts]))
            else:
                feature.setGeometry(QgsGeometry.fromPolylineXY(pts))
            if self.export_geom:
                attr = feature.attributes()
                attr.append(pt_orig_x)
                attr.append(pt_orig_y)
                feature.setAttributes(attr)
        except Exception:
            s = traceback.format_exc()
            feedback.pushInfo(s)
            self.num_bad += 1
            return []
        return [feature]

    def postProcessAlgorithm(self, context, feedback):
        if self.num_bad:
            feedback.pushInfo(tr("{} out of {} features had invalid parameters and were ignored.".format(self.num_bad, self.total_features)))
        return {}