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

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

"""
***************************************************************************
    RasterLayerCalculator.py
    ---------------------
    Date                 : November 2016
    Copyright            : (C) 2016 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.                                   *
*                                                                         *
***************************************************************************
"""
from processing.modeler.ModelerAlgorithm import ValueFromInput, ValueFromOutput
import os

__author__ = 'Victor Olaya'
__date__ = 'November 2016'
__copyright__ = '(C) 2016, Victor Olaya'

# This will get replaced with a git SHA1 when you do a git archive

__revision__ = '$Format:%H$'

import math
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
from processing.core.parameters import ParameterMultipleInput, ParameterExtent, ParameterString, ParameterRaster, ParameterNumber
from processing.core.outputs import OutputRaster
from processing.tools import dataobjects
from processing.algs.gdal.GdalUtils import GdalUtils
from qgis.core import (QgsApplication,
                       QgsRectangle,
                       QgsProcessingUtils,
                       QgsProject)
from qgis.analysis import QgsRasterCalculator, QgsRasterCalculatorEntry
from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
from processing.algs.qgis.ui.RasterCalculatorWidgets import LayersListWidgetWrapper, ExpressionWidgetWrapper


class RasterCalculator(QgisAlgorithm):

    LAYERS = 'LAYERS'
    EXTENT = 'EXTENT'
    CELLSIZE = 'CELLSIZE'
    EXPRESSION = 'EXPRESSION'
    OUTPUT = 'OUTPUT'

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

    def __init__(self):
        super().__init__()
        self.addParameter(ParameterMultipleInput(self.LAYERS,
                                                 self.tr('Input layers'),
                                                 datatype=dataobjects.TYPE_RASTER,
                                                 optional=True,
                                                 metadata={'widget_wrapper': LayersListWidgetWrapper}))

        class ParameterRasterCalculatorExpression(ParameterString):

            def evaluateForModeler(self, value, model):
                for i in list(model.inputs.values()):
                    param = i.param
                    if isinstance(param, ParameterRaster):
                        new = "{}@".format(os.path.basename(param.value))
                        old = "{}@".format(param.name())
                        value = value.replace(old, new)

                    for alg in list(model.algs.values()):
                        for out in alg.algorithm.outputs:
                            if isinstance(out, OutputRaster):
                                if out.value:
                                    new = "{}@".format(os.path.basename(out.value))
                                    old = "{}:{}@".format(alg.modeler_name, out.name)
                                    value = value.replace(old, new)
                return value

        self.addParameter(ParameterRasterCalculatorExpression(self.EXPRESSION, self.tr('Expression'),
                                                              multiline=True,
                                                              metadata={'widget_wrapper': ExpressionWidgetWrapper}))
        self.addParameter(ParameterNumber(self.CELLSIZE,
                                          self.tr('Cell size (use 0 or empty to set it automatically)'),
                                          minValue=0.0, default=0.0, optional=True))
        self.addParameter(ParameterExtent(self.EXTENT,
                                          self.tr('Output extent'),
                                          optional=True))
        self.addOutput(OutputRaster(self.OUTPUT, self.tr('Output')))

    def name(self):
        return 'rastercalculator'

    def displayName(self):
        return self.tr('Raster calculator')

    def processAlgorithm(self, parameters, context, feedback):
        expression = self.getParameterValue(self.EXPRESSION)
        layersValue = self.getParameterValue(self.LAYERS)
        layersDict = {}
        if layersValue:
            layers = [QgsProcessingUtils.mapLayerFromString(f, context) for f in layersValue.split(";")]
            layersDict = {os.path.basename(lyr.source().split(".")[0]): lyr for lyr in layers}

        for lyr in QgsProcessingUtils.compatibleRasterLayers(QgsProject.instance()):
            name = lyr.name()
            if (name + "@") in expression:
                layersDict[name] = lyr

        entries = []
        for name, lyr in layersDict.items():
            for n in range(lyr.bandCount()):
                entry = QgsRasterCalculatorEntry()
                entry.ref = '{:s}@{:d}'.format(name, n + 1)
                entry.raster = lyr
                entry.bandNumber = n + 1
                entries.append(entry)

        output = self.getOutputValue(self.OUTPUT)
        extentValue = self.getParameterValue(self.EXTENT)
        if not extentValue:
            extentValue = QgsProcessingUtils.combineLayerExtents(layersValue)

        if extentValue:
            extent = extentValue.split(',')
            bbox = QgsRectangle(float(extent[0]), float(extent[2]),
                                float(extent[1]), float(extent[3]))
        else:
            if layersDict:
                bbox = list(layersDict.values())[0].extent()
                for lyr in layersDict.values():
                    bbox.combineExtentWith(lyr.extent())
            else:
                raise GeoAlgorithmExecutionException(self.tr("No layers selected"))

        def _cellsize(layer):
            return (layer.extent().xMaximum() - layer.extent().xMinimum()) / layer.width()
        cellsize = self.getParameterValue(self.CELLSIZE) or min([_cellsize(lyr) for lyr in layersDict.values()])
        width = math.floor((bbox.xMaximum() - bbox.xMinimum()) / cellsize)
        height = math.floor((bbox.yMaximum() - bbox.yMinimum()) / cellsize)
        driverName = GdalUtils.getFormatShortNameFromFilename(output)
        calc = QgsRasterCalculator(expression,
                                   output,
                                   driverName,
                                   bbox,
                                   width,
                                   height,
                                   entries)

        res = calc.processCalculation()
        if res == QgsRasterCalculator.ParserError:
            raise GeoAlgorithmExecutionException(self.tr("Error parsing formula"))

    def processBeforeAddingToModeler(self, algorithm, model):
        values = []
        expression = algorithm.params[self.EXPRESSION]
        for i in list(model.inputs.values()):
            param = i.param
            if isinstance(param, ParameterRaster) and "{}@".format(param.name) in expression:
                values.append(ValueFromInput(param.name()))

        if algorithm.name:
            dependent = model.getDependentAlgorithms(algorithm.name)
        else:
            dependent = []
        for alg in list(model.algs.values()):
            if alg.modeler_name not in dependent:
                for out in alg.algorithm.outputs:
                    if (isinstance(out, OutputRaster) and
                            "{}:{}@".format(alg.modeler_name, out.name) in expression):
                        values.append(ValueFromOutput(alg.modeler_name, out.name))

        algorithm.params[self.LAYERS] = values