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

"""
***************************************************************************
    EquivalentNumField.py
    ---------------------
    Date                 : January 2013
    Copyright            : (C) 2013 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.                                   *
*                                                                         *
***************************************************************************
"""

__author__ = 'Victor Olaya'
__date__ = 'January 2013'
__copyright__ = '(C) 2013, Victor Olaya'

import warnings
from qgis.core import (QgsProcessingException,
                       QgsProcessingParameterFeatureSource,
                       QgsProcessingParameterField,
                       QgsProcessingParameterFileDestination,
                       QgsProcessingParameterString,
                       QgsProcessingParameterBoolean)

from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
from processing.tools import vector

from qgis.PyQt.QtCore import QCoreApplication


class VectorLayerScatterplot(QgisAlgorithm):
    INPUT = 'INPUT'
    OUTPUT = 'OUTPUT'
    XFIELD = 'XFIELD'
    YFIELD = 'YFIELD'
    TITLE = 'TITLE'
    XAXIS_TITLE = "XAXIS_TITLE"
    YAXIS_TITLE = "YAXIS_TITLE"
    XAXIS_LOG = "XAXIS_LOG"
    YAXIS_LOG = "YAXIS_LOG"

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

    def groupId(self):
        return 'plots'

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

    def initAlgorithm(self, config=None):
        self.addParameter(QgsProcessingParameterFeatureSource(self.INPUT,
                                                              self.tr('Input layer')))
        self.addParameter(QgsProcessingParameterField(self.XFIELD,
                                                      self.tr('X attribute'),
                                                      parentLayerParameterName=self.INPUT,
                                                      type=QgsProcessingParameterField.DataType.Numeric))
        self.addParameter(QgsProcessingParameterField(self.YFIELD,
                                                      self.tr('Y attribute'),
                                                      parentLayerParameterName=self.INPUT,
                                                      type=QgsProcessingParameterField.DataType.Numeric))

        self.addParameter(QgsProcessingParameterString(
            self.TITLE,
            self.tr('Title'),
            optional=True))

        self.addParameter(QgsProcessingParameterString(
            self.XAXIS_TITLE,
            self.tr('Xaxis Title'),
            optional=True))

        self.addParameter(QgsProcessingParameterString(
            self.YAXIS_TITLE,
            self.tr('Yaxis Title'),
            optional=True))

        self.addParameter(QgsProcessingParameterBoolean(
            self.XAXIS_LOG,
            self.tr('Xaxis logarithmic'),
            defaultValue=False,
            optional=True))

        self.addParameter(QgsProcessingParameterBoolean(
            self.YAXIS_LOG,
            self.tr('Yaxis logarithmic'),
            defaultValue=False,
            optional=True))

        self.addParameter(QgsProcessingParameterFileDestination(self.OUTPUT, self.tr('Scatterplot'), self.tr('HTML files (*.html)')))

    def name(self):
        return 'vectorlayerscatterplot'

    def displayName(self):
        return self.tr('Vector layer scatterplot')

    def processAlgorithm(self, parameters, context, feedback):
        try:
            # importing plotly throws Python warnings from within the library - filter these out
            with warnings.catch_warnings():
                warnings.filterwarnings("ignore", category=ResourceWarning)
                warnings.filterwarnings("ignore", category=ImportWarning)
                import plotly as plt
                import plotly.graph_objs as go
        except ImportError:
            raise QgsProcessingException(QCoreApplication.translate('VectorLayerScatterplot', 'This algorithm requires the Python “plotly” library. Please install this library and try again.'))

        source = self.parameterAsSource(parameters, self.INPUT, context)
        if source is None:
            raise QgsProcessingException(self.invalidSourceError(parameters, self.INPUT))

        xfieldname = self.parameterAsString(parameters, self.XFIELD, context)
        yfieldname = self.parameterAsString(parameters, self.YFIELD, context)

        title = self.parameterAsString(parameters, self.TITLE, context)
        xaxis_title = self.parameterAsString(parameters, self.XAXIS_TITLE, context)
        yaxis_title = self.parameterAsString(parameters, self.YAXIS_TITLE, context)
        xaxis_log = self.parameterAsBool(parameters, self.XAXIS_LOG, context)
        yaxis_log = self.parameterAsBool(parameters, self.YAXIS_LOG, context)

        if title.strip() == "":
            title = None
        if xaxis_title == "":
            xaxis_title = xfieldname
        elif xaxis_title == " ":
            xaxis_title = None
        if yaxis_title == "":
            yaxis_title = yfieldname
        elif yaxis_title == " ":
            yaxis_title = None

        output = self.parameterAsFileOutput(parameters, self.OUTPUT, context)

        values = vector.values(source, xfieldname, yfieldname)
        data = [go.Scatter(x=values[xfieldname],
                           y=values[yfieldname],
                           mode='markers')]
        fig = go.Figure(
            data=data,
            layout_title_text=title,
            layout_xaxis_title=xaxis_title,
            layout_yaxis_title=yaxis_title)

        if xaxis_log:
            fig.update_xaxes(type="log")

        if yaxis_log:
            fig.update_yaxes(type="log")

        fig.write_html(output)

        return {self.OUTPUT: output}