citydb_explorer.py

#####################################################################################
# Copyright (C) 2021
# Chair of Geoinformatics
# Technical University of Munich, Germany
# https://www.gis.bgu.tum.de/
#
# This source 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.
#
# This code is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
# The 3D City Database is jointly developed with the following cooperation partners:
#
# virtualcitySYSTEMS GmbH, Berlin <http://www.virtualcitysystems.de/>
# M.O.S.S. Computer Grafik Systeme GmbH, Taufkirchen <http://www.moss.de/>
#
#####################################################################################

import os.path

from qgis.PyQt.QtCore import QCoreApplication, QSettings, Qt, QTranslator
from qgis.PyQt.QtGui import QIcon
from qgis.PyQt.QtWidgets import QAction

from .citydb_explorer_dockwidget import CityDbExplorerDockWidget
from .resources import *  # noqa F403


class CityDbExplorer:
    """QGIS Plugin Implementation."""

    def __init__(self, iface):
        """Constructor.

        :param iface: An interface instance that will be passed to this class
            which provides the hook by which you can manipulate the QGIS
            application at run time.
        :type iface: QgsInterface
        """
        # Save reference to the QGIS interface
        self.iface = iface

        # initialize plugin directory
        self.plugin_dir = os.path.dirname(__file__)

        # initialize locale
        locale = QSettings().value("locale/userLocale")[0:2]
        locale_path = os.path.join(
            self.plugin_dir, "i18n", "CityDbExplorer_{}.qm".format(locale)
        )

        if os.path.exists(locale_path):
            self.translator = QTranslator()
            self.translator.load(locale_path)
            QCoreApplication.installTranslator(self.translator)

        # Declare instance attributes
        self.actions = []
        self.menu = "3DCityDB Explorer"
        self.toolbar = self.iface.addToolBar(u"CityDbExplorer")
        self.toolbar.setObjectName(u"CityDbExplorer")

        self.pluginIsActive = False
        self.dockwidget = None

    # noinspection PyMethodMayBeStatic
    def tr(self, message):
        """Get the translation for a string using Qt translation API.

        We implement this ourselves since we do not inherit QObject.

        :param message: String for translation.
        :type message: str, QString

        :returns: Translated version of message.
        :rtype: QString
        """
        # noinspection PyTypeChecker,PyArgumentList,PyCallByClass
        return QCoreApplication.translate("CityDbExplorer", message)

    def add_action(
        self,
        icon_path,
        text,
        callback,
        enabled_flag=True,
        add_to_menu=True,
        add_to_toolbar=True,
        status_tip=None,
        whats_this=None,
        parent=None,
    ):
        """Add a toolbar icon to the toolbar.

        :param icon_path: Path to the icon for this action. Can be a resource
            path (e.g. ':/plugins/foo/bar.png') or a normal file system path.
        :type icon_path: str

        :param text: Text that should be shown in menu items for this action.
        :type text: str

        :param callback: Function to be called when the action is triggered.
        :type callback: function

        :param enabled_flag: A flag indicating if the action should be enabled
            by default. Defaults to True.
        :type enabled_flag: bool

        :param add_to_menu: Flag indicating whether the action should also
            be added to the menu. Defaults to True.
        :type add_to_menu: bool

        :param add_to_toolbar: Flag indicating whether the action should also
            be added to the toolbar. Defaults to True.
        :type add_to_toolbar: bool

        :param status_tip: Optional text to show in a popup when mouse pointer
            hovers over the action.
        :type status_tip: str

        :param parent: Parent widget for the new action. Defaults None.
        :type parent: QWidget

        :param whats_this: Optional text to show in the status bar when the
            mouse pointer hovers over the action.

        :returns: The action that was created. Note that the action is also
            added to self.actions list.
        :rtype: QAction
        """

        icon = QIcon(icon_path)
        action = QAction(icon, text, parent)
        action.triggered.connect(callback)
        action.setEnabled(enabled_flag)

        if status_tip is not None:
            action.setStatusTip(status_tip)

        if whats_this is not None:
            action.setWhatsThis(whats_this)

        if add_to_toolbar:
            self.toolbar.addAction(action)

        if add_to_menu:
            self.iface.addPluginToDatabaseMenu(self.menu, action)

        self.actions.append(action)

        return action

    def initGui(self):
        """Create the menu entries and toolbar icons inside the QGIS GUI."""

        icon_path = ":/plugins/citydb_explorer/icon.png"
        self.add_action(
            icon_path,
            text=self.tr(u"Open Widget"),
            callback=self.run,
            parent=self.iface.mainWindow(),
        )

    # --------------------------------------------------------------------------

    def onClosePlugin(self):
        """Cleanup necessary items here when plugin dockwidget is closed"""

        # disconnects
        self.dockwidget.closingPlugin.disconnect(self.onClosePlugin)

        # remove this statement if dockwidget is to remain
        # for reuse if plugin is reopened
        # Commented next statement since it causes QGIS crashes
        # when closing the docked window:
        # self.dockwidget = None

        self.pluginIsActive = False

    def unload(self):
        """Removes the plugin menu item and icon from QGIS GUI."""

        for action in self.actions:
            self.iface.removePluginDatabaseMenu(self.tr(u"&3DCityDB Explorer"), action)
            self.iface.removeToolBarIcon(action)
        # remove the toolbar
        del self.toolbar

    # --------------------------------------------------------------------------

    def run(self):
        """Run method that loads and starts the plugin"""

        if not self.pluginIsActive:
            self.pluginIsActive = True

            # print "** STARTING CityDbExplorer"

            # dockwidget may not exist if:
            #    first run of plugin
            #    removed on close (see self.onClosePlugin method)
            if self.dockwidget is None:
                # Create the dockwidget (after translation) and keep reference
                self.dockwidget = CityDbExplorerDockWidget(self.iface)

            # connect to provide cleanup on closing of dockwidget
            self.dockwidget.closingPlugin.connect(self.onClosePlugin)

            # show the dockwidget
            # TODO: fix to allow choice of dock location
            self.iface.addDockWidget(Qt.LeftDockWidgetArea, self.dockwidget)
            self.dockwidget.show()