QGIS/python/plugins/processing/algs/qgis/Relief.py

# -*- coding: utf-8 -*-

"""
***************************************************************************
    Relief.py
    ---------------------
    Date                 : December 2016
    Copyright            : (C) 2016 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.                                   *
*                                                                         *
***************************************************************************
"""

__author__ = 'Alexander Bruy'
__date__ = 'December 2016'
__copyright__ = '(C) 2016, Alexander Bruy'

# 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, QColor

from qgis.analysis import QgsRelief
from qgis.core import (QgsProcessingParameterDefinition,
                       QgsProcessingParameterRasterLayer,
                       QgsProcessingParameterNumber,
                       QgsProcessingParameterBoolean,
                       QgsProcessingParameterRasterDestination,
                       QgsProcessingParameterFileDestination,
                       QgsRasterFileWriter,
                       QgsProcessingException)
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
from processing.tools.dataobjects import exportRasterLayer

pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]


class ParameterReliefColors(QgsProcessingParameterDefinition):

    def __init__(self, name='', description='', parent=None, optional=True):
        super().__init__(name, description, None, optional)
        self.parent = parent
        self.setMetadata({'widget_wrapper': 'processing.algs.qgis.ui.ReliefColorsWidget.ReliefColorsWidgetWrapper'})

    def type(self):
        return 'relief_colors'

    def clone(self):
        return ParameterReliefColors(self.name(), self.description(), self.parent,
                                     self.flags() & QgsProcessingParameterDefinition.FlagOptional)

    @staticmethod
    def valueToColors(value):
        if value is None:
            return None

        if value == '':
            return None

        if isinstance(value, str):
            return value.split(';')
        else:
            return ParameterReliefColors.colorsToString(value)

    @staticmethod
    def colorsToString(colors):
        s = ''
        for c in colors:
            s += '{:f}, {:f}, {:d}, {:d}, {:d};'.format(c[0],
                                                        c[1],
                                                        c[2],
                                                        c[3],
                                                        c[4])
        return s[:-1]


class Relief(QgisAlgorithm):

    INPUT = 'INPUT'
    Z_FACTOR = 'Z_FACTOR'
    AUTO_COLORS = 'AUTO_COLORS'
    COLORS = 'COLORS'
    OUTPUT = 'OUTPUT'
    FREQUENCY_DISTRIBUTION = 'FREQUENCY_DISTRIBUTION'

    def icon(self):
        return QIcon(os.path.join(pluginPath, 'images', 'dem.png'))

    def group(self):
        return self.tr('Raster terrain analysis')

    def __init__(self):
        super().__init__()

    def initAlgorithm(self, config=None):
        self.addParameter(QgsProcessingParameterRasterLayer(self.INPUT,
                                                            self.tr('Elevation layer')))
        self.addParameter(QgsProcessingParameterNumber(self.Z_FACTOR,
                                                       self.tr('Z factor'), type=QgsProcessingParameterNumber.Double,
                                                       minValue=0.00, maxValue=999999.99, defaultValue=1.0))
        self.addParameter(QgsProcessingParameterBoolean(self.AUTO_COLORS,
                                                        self.tr('Generate relief classes automatically'),
                                                        defaultValue=False))
        self.addParameter(ParameterReliefColors(self.COLORS,
                                                self.tr('Relief colors'),
                                                self.INPUT,
                                                True))
        self.addParameter(QgsProcessingParameterRasterDestination(self.OUTPUT,
                                                                  self.tr('Relief')))
        self.addParameter(QgsProcessingParameterFileDestination(self.FREQUENCY_DISTRIBUTION,
                                                                self.tr('Frequency distribution'), 'CSV files (*.csv)', optional=True))

    def name(self):
        return 'relief'

    def displayName(self):
        return self.tr('Relief')

    def processAlgorithm(self, parameters, context, feedback):
        inputFile = exportRasterLayer(self.parameterAsRasterLayer(parameters, self.INPUT, context))
        zFactor = self.parameterAsDouble(parameters, self.Z_FACTOR, context)
        automaticColors = self.parameterAsBool(parameters, self.AUTO_COLORS, context)
        outputFile = self.parameterAsOutputLayer(parameters, self.OUTPUT, context)
        frequencyDistribution = self.parameterAsFileOutput(parameters, self.FREQUENCY_DISTRIBUTION, context)

        outputFormat = QgsRasterFileWriter.driverForExtension(os.path.splitext(outputFile)[1])

        relief = QgsRelief(inputFile, outputFile, outputFormat)

        if automaticColors:
            reliefColors = relief.calculateOptimizedReliefClasses()
        else:
            colors = ParameterReliefColors.valueToColors(parameters[self.COLORS])
            if colors is None or len(colors) == 0:
                raise QgsProcessingException(
                    self.tr('Specify relief colors or activate "Generate relief classes automatically" option.'))

            reliefColors = []
            for c in colors:
                v = c.split(',')
                color = QgsRelief.ReliefColor(QColor(int(v[2]), int(v[3]), int(v[4])),
                                              float(v[0]),
                                              float(v[1]))
                reliefColors.append(color)

        relief.setReliefColors(reliefColors)
        relief.setZFactor(zFactor)
        if frequencyDistribution:
            relief.exportFrequencyDistributionToCsv(frequencyDistribution)
        relief.processRaster(feedback)

        return {self.OUTPUT: outputFile, self.FREQUENCY_DISTRIBUTION: frequencyDistribution}