classificationscheme.py

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

"""
***************************************************************************
    classificationscheme.py

    Methods and Objects to describe raster classifications
    ---------------------
    Date                 : Juli 2017
    Copyright            : (C) 2017 by Benjamin Jakimow
    Email                : benjamin.jakimow@geo.hu-berlin.de
***************************************************************************
*                                                                         *
*   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, json, pickle, warnings, csv, re, sys
from qgis.core import *
from qgis.gui import *
from qgis.PyQt.QtCore import *
from qgis.PyQt.QtGui import *
from qgis.PyQt.QtWidgets import *
import numpy as np
from osgeo import gdal
from qps.utils import gdalDataset, nextColor, loadUIFormClass, findMapLayer, registeredMapLayers


loadClassificationUI = lambda name: loadUIFormClass(os.path.join(os.path.dirname(__file__), name))

DEFAULT_UNCLASSIFIEDCOLOR = QColor('black')
DEFAULT_FIRST_COLOR = QColor('#a6cee3')

MIMEDATA_KEY = 'hub-classscheme'
MIMEDATA_KEY_TEXT = 'text/plain'
MIMEDATA_INTERNAL_IDs = 'classinfo_ids'


def findMapLayersWithClassInfo()->list:
    """
    Returns QgsMapLayers from which a ClassificationScheme can be derived.
    Searches in all QgsMapLayerStores known to classification.MAP_LAYER_STORES
    :return: [list-of-QgsMapLayer]
    """

    results = []
    for lyr in registeredMapLayers():
        if isinstance(lyr, QgsVectorLayer) and isinstance(lyr.renderer(), QgsCategorizedSymbolRenderer):
            results.append(lyr)
        elif isinstance(lyr, QgsRasterLayer) and isinstance(lyr.renderer(), QgsPalettedRasterRenderer):
            results.append(lyr)
    return results




def hasClassification(pathOrDataset):
    """
    This function tests if a gdal-readable raster data set contains
    categorical information that can be used to retrieve a ClassificationScheme
    :param pathOrDataset: string | gdal.Dataset
    :return: True | False
    """
    ds = None
    try:
        if isinstance(pathOrDataset, gdal.Dataset):
            ds = pathOrDataset
        elif isinstance(pathOrDataset, str):
            ds = gdal.Open(pathOrDataset)
        elif isinstance(ds, QgsRasterLayer):
            ds = gdal.Open(ds.source())
    except Exception as ex:
        pass

    if not isinstance(ds, gdal.Dataset):
        return False

    for b in range(ds.RasterCount):
        band = ds.GetRasterBand(b + 1)
        assert isinstance(band, gdal.Band)
        if band.GetCategoryNames() or band.GetColorTable():
            return True
    return False


def getTextColorWithContrast(c:QColor)->QColor:
    """
    Returns a QColor with good contrast to c
    :param c: QColor
    :return: QColor
    """
    assert isinstance(c, QColor)
    if c.lightness() < 0.5:
        return QColor('white')
    else:
        return QColor('black')



class ClassInfo(QObject):
    sigSettingsChanged = pyqtSignal()

    def __init__(self, label=0, name=None, color=None, parent=None):
        super(ClassInfo, self).__init__(parent)

        if name is None:
            name = 'Unclassified' if label == 0 else 'Class {}'.format(label)

        if color is None:
            if label == 0:
                color = DEFAULT_UNCLASSIFIEDCOLOR
            else:
                color = DEFAULT_FIRST_COLOR


        self.mName = name
        self.mLabel = label
        self.mColor = color
        if color:
            self.setColor(color)


    def setLabel(self, label:int):
        """
        Sets the label value.
        :param label: int, must be >= 0
        """
        assert isinstance(label, int)
        assert label >= 0
        self.mLabel = label
        self.sigSettingsChanged.emit()

    def label(self)->int:
        """
        Returns the class label values
        :return: int
        """
        return self.mLabel

    def color(self)->QColor:
        """
        Returns the class color.
        :return: QColor
        """
        return QColor(self.mColor)

    def name(self)->str:
        """
        Returns the class name
        :return: str
        """
        return self.mName

    def setColor(self, color:QColor):
        """
        Sets the class color.
        :param color: QColor
        """
        assert isinstance(color, QColor)
        self.mColor = color
        self.sigSettingsChanged.emit()

    def setName(self, name:str):
        """
        Sets thes class name
        :param name: str
        """
        assert isinstance(name, str)
        self.mName = name
        self.sigSettingsChanged.emit()


    def pixmap(self, *args)->QPixmap:
        """
        Returns a QPixmap. Default size is 20x20px
        :param args: QPixmap arguments.
        :return: QPixmap
        """
        if len(args) == 0:
            args = (QSize(20, 20),)

        pm = QPixmap(*args)
        pm.fill(self.mColor)
        return pm

    def icon(self, *args)->QIcon:
        """
        Returns the class color as QIcon
        :param args: QPixmap arguments
        :return: QIcon
        """
        return QIcon(self.pixmap(*args))

    def clone(self):
        """
        Create a copy of this ClassInfo