def __init__(self, parent=None, iface=None):
        """Constructor for import dialog.

        :param parent: Optional widget to use as parent
        :type parent: QWidget

        :param iface: An instance of QGisInterface
        :type iface: QGisInterface
        """
        QDialog.__init__(self, parent)
        self.parent = parent
        self.setupUi(self)

        self.setWindowTitle(self.tr('InaSAFE OpenStreetMap Downloader'))

        self.iface = iface
        self.buildings_url = 'http://osm.linfiniti.com/buildings-shp'
        self.building_points_url = \
            'http://osm.linfiniti.com/building-points-shp'
        self.roads_url = 'http://osm.linfiniti.com/roads-shp'

        self.help_context = 'openstreetmap_downloader'
        # creating progress dialog for download
        self.progress_dialog = QProgressDialog(self)
        self.progress_dialog.setAutoClose(False)
        title = self.tr('InaSAFE OpenStreetMap Downloader')
        self.progress_dialog.setWindowTitle(title)
        # Set up context help
        help_button = self.button_box.button(QtGui.QDialogButtonBox.Help)
        help_button.clicked.connect(self.show_help)

        self.show_info()

        # set up the validator for the file name prefix
        expression = QRegExp('^[A-Za-z0-9-_]*$')
        validator = QRegExpValidator(expression, self.filename_prefix)
        self.filename_prefix.setValidator(validator)

        # Set Proxy in webpage
        proxy = get_proxy()
        self.network_manager = QNetworkAccessManager(self)
        if proxy is not None:
            self.network_manager.setProxy(proxy)
        self.restore_state()

        # Setup the rectangle map tool
        self.canvas = iface.mapCanvas()
        self.rectangle_map_tool = \
            RectangleMapTool(self.canvas)
        self.rectangle_map_tool.rectangle_created.connect(
            self.update_extent_from_rectangle)
        self.button_extent_rectangle.clicked.connect(
            self.drag_rectangle_on_map_canvas)

        # Setup pan tool
        self.pan_tool = QgsMapToolPan(self.canvas)
        self.canvas.setMapTool(self.pan_tool)
        self.update_extent_from_map_canvas()

    def __init__(self, iface, parent=None, extent=None, crs=None):
        """Constructor for the dialog.

        :param iface: A Quantum GIS QGisAppInterface instance.
        :type iface: QGisAppInterface

        :param parent: Parent widget of this dialog
        :type parent: QWidget

        :param extent: Extent of the user's preferred analysis area.
        :type extent: QgsRectangle

        :param crs: Coordinate reference system for user defined analysis
            extent.
        :type crs: QgsCoordinateReferenceSystem
        """
        QDialog.__init__(self, parent)
        self.setupUi(self)

        self.iface = iface
        self.parent = parent
        self.canvas = iface.mapCanvas()
        self.previous_map_tool = None
        # Prepare the map tool
        self.tool = RectangleMapTool(self.canvas)
        self.previous_map_tool = self.canvas.mapTool()

        if extent is None and crs is None:
            # Use the current map canvas extents as a starting point
            self.tool.set_rectangle(self.canvas.extent())
        else:
            # Ensure supplied extent is in current canvas crs
            transform = QgsCoordinateTransform(
                crs,
                self.canvas.mapRenderer().destinationCrs())
            transformed_extent = transform.transformBoundingBox(extent)
            self.tool.set_rectangle(transformed_extent)

        self._populate_coordinates()

        # Observe inputs for changes
        self.x_minimum.valueChanged.connect(self._coordinates_changed)
        self.y_minimum.valueChanged.connect(self._coordinates_changed)
        self.x_maximum.valueChanged.connect(self._coordinates_changed)
        self.y_maximum.valueChanged.connect(self._coordinates_changed)

        # Draw the rubberband
        self._coordinates_changed()

        # Wire up button events
        self.capture_button.clicked.connect(self.start_capture)
        # Handle cancel
        cancel_button = self.button_box.button(QtGui.QDialogButtonBox.Cancel)
        cancel_button.clicked.connect(self.reject)
        # Make sure to reshow this dialog when rectangle is captured
        self.tool.rectangle_created.connect(self.stop_capture)
        # Setup ok button
        self.ok_button = self.button_box.button(QtGui.QDialogButtonBox.Ok)
        self.ok_button.clicked.connect(self.accept)
        # Set up context help
        self.help_button = self.button_box.button(QtGui.QDialogButtonBox.Help)
        # Allow toggling the help button
        self.help_button.setCheckable(True)
        self.help_button.toggled.connect(self.help_toggled)
        self.main_stacked_widget.setCurrentIndex(1)
        # Reset / Clear button
        clear_button = self.button_box.button(QtGui.QDialogButtonBox.Reset)
        clear_button.setText(self.tr('Clear'))
        clear_button.clicked.connect(self.clear)

        # Populate the bookmarks list and connect the combobox
        self._populate_bookmarks_list()
        self.bookmarks_list.currentIndexChanged.connect(
            self.bookmarks_index_changed)

        # Reinstate the last used radio button
        settings = QSettings()
        mode = settings.value(
            'inasafe/analysis_extents_mode',
            'HazardExposureView')
        if mode == 'HazardExposureView':
            self.hazard_exposure_view_extent.setChecked(True)
        elif mode == 'HazardExposure':
            self.hazard_exposure_only.setChecked(True)
        elif mode == 'HazardExposureBookmark':
            self.hazard_exposure_bookmark.setChecked(True)
        elif mode == 'HazardExposureBoundingBox':
            self.hazard_exposure_user_extent.setChecked(True)

        show_warnings = settings.value(
            'inasafe/show_extent_warnings',
            True,
            type=bool)
        if show_warnings:
            self.show_warnings.setChecked(True)
        else:
            self.show_warnings.setChecked(False)

        show_confirmations = settings.value(
            'inasafe/show_extent_confirmations',
#.........这里部分代码省略.........

class ExtentSelectorDialog(QDialog, FORM_CLASS):
    """Dialog for letting user determine analysis extents.
    """

    extent_defined = pyqtSignal(QgsRectangle, QgsCoordinateReferenceSystem)
    clear_extent = pyqtSignal()
    extent_selector_closed = pyqtSignal()

    def __init__(self, iface, parent=None, extent=None, crs=None):
        """Constructor for the dialog.

        :param iface: A Quantum GIS QGisAppInterface instance.
        :type iface: QGisAppInterface

        :param parent: Parent widget of this dialog
        :type parent: QWidget

        :param extent: Extent of the user's preferred analysis area.
        :type extent: QgsRectangle

        :param crs: Coordinate reference system for user defined analysis
            extent.
        :type crs: QgsCoordinateReferenceSystem
        """
        QDialog.__init__(self, parent)
        self.setupUi(self)

        self.iface = iface
        self.parent = parent
        self.canvas = iface.mapCanvas()
        self.previous_map_tool = None
        # Prepare the map tool
        self.tool = RectangleMapTool(self.canvas)
        self.previous_map_tool = self.canvas.mapTool()

        if extent is None and crs is None:
            # Use the current map canvas extents as a starting point
            self.tool.set_rectangle(self.canvas.extent())
        else:
            # Ensure supplied extent is in current canvas crs
            transform = QgsCoordinateTransform(
                crs,
                self.canvas.mapRenderer().destinationCrs())
            transformed_extent = transform.transformBoundingBox(extent)
            self.tool.set_rectangle(transformed_extent)

        self._populate_coordinates()

        # Observe inputs for changes
        self.x_minimum.valueChanged.connect(self._coordinates_changed)
        self.y_minimum.valueChanged.connect(self._coordinates_changed)
        self.x_maximum.valueChanged.connect(self._coordinates_changed)
        self.y_maximum.valueChanged.connect(self._coordinates_changed)

        # Draw the rubberband
        self._coordinates_changed()

        # Wire up button events
        self.capture_button.clicked.connect(self.start_capture)
        # Handle cancel
        cancel_button = self.button_box.button(QtGui.QDialogButtonBox.Cancel)
        cancel_button.clicked.connect(self.reject)
        # Make sure to reshow this dialog when rectangle is captured
        self.tool.rectangle_created.connect(self.stop_capture)
        # Setup ok button
        self.ok_button = self.button_box.button(QtGui.QDialogButtonBox.Ok)
        self.ok_button.clicked.connect(self.accept)
        # Set up context help
        self.help_button = self.button_box.button(QtGui.QDialogButtonBox.Help)
        # Allow toggling the help button
        self.help_button.setCheckable(True)
        self.help_button.toggled.connect(self.help_toggled)
        self.main_stacked_widget.setCurrentIndex(1)
        # Reset / Clear button
        clear_button = self.button_box.button(QtGui.QDialogButtonBox.Reset)
        clear_button.setText(self.tr('Clear'))
        clear_button.clicked.connect(self.clear)

        # Populate the bookmarks list and connect the combobox
        self._populate_bookmarks_list()
        self.bookmarks_list.currentIndexChanged.connect(
            self.bookmarks_index_changed)

        # Reinstate the last used radio button
        settings = QSettings()
        mode = settings.value(
            'inasafe/analysis_extents_mode',
            'HazardExposureView')
        if mode == 'HazardExposureView':
            self.hazard_exposure_view_extent.setChecked(True)
        elif mode == 'HazardExposure':
            self.hazard_exposure_only.setChecked(True)
        elif mode == 'HazardExposureBookmark':
            self.hazard_exposure_bookmark.setChecked(True)
        elif mode == 'HazardExposureBoundingBox':
            self.hazard_exposure_user_extent.setChecked(True)

        show_warnings = settings.value(
            'inasafe/show_extent_warnings',
            True,
#.........这里部分代码省略.........

    def __init__(self, parent=None, iface=None):
        """Constructor for import dialog.

        :param parent: Optional widget to use as parent
        :type parent: QWidget

        :param iface: An instance of QGisInterface
        :type iface: QGisInterface
        """
        QDialog.__init__(self, parent)
        self.parent = parent
        self.setupUi(self)

        self.setWindowTitle(self.tr('InaSAFE OpenStreetMap Downloader'))

        self.iface = iface

        self.help_context = 'openstreetmap_downloader'
        # creating progress dialog for download
        self.progress_dialog = QProgressDialog(self)
        self.progress_dialog.setAutoClose(False)
        title = self.tr('InaSAFE OpenStreetMap Downloader')
        self.progress_dialog.setWindowTitle(title)
        # Set up context help
        self.help_button = self.button_box.button(QtGui.QDialogButtonBox.Help)
        # Allow toggling the help button
        self.help_button.setCheckable(True)
        self.help_button.toggled.connect(self.help_toggled)
        self.stacked_widget.setCurrentIndex(1)
        # Disable boundaries group box until boundary checkbox is ticked
        self.boundary_group.setEnabled(False)

        # set up the validator for the file name prefix
        expression = QRegExp('^[A-Za-z0-9-_]*$')
        validator = QRegExpValidator(expression, self.filename_prefix)
        self.filename_prefix.setValidator(validator)

        self.restore_state()

        # Setup the rectangle map tool
        self.canvas = iface.mapCanvas()
        self.rectangle_map_tool = \
            RectangleMapTool(self.canvas)
        self.rectangle_map_tool.rectangle_created.connect(
            self.update_extent_from_rectangle)
        self.capture_button.clicked.connect(
            self.drag_rectangle_on_map_canvas)

        # Setup pan tool
        self.pan_tool = QgsMapToolPan(self.canvas)
        self.canvas.setMapTool(self.pan_tool)

        # Setup helper for admin_level
        json_file_path = resources_path('osm', 'admin_level_per_country.json')
        if os.path.isfile(json_file_path):
            self.countries = json.load(open(json_file_path))
            self.bbox_countries = None
            self.populate_countries()
            # connect
            self.country_comboBox.currentIndexChanged.connect(
                self.update_helper_political_level)
            self.admin_level_comboBox.currentIndexChanged.connect(
                self.update_helper_political_level)

        self.update_extent_from_map_canvas()

class OsmDownloaderDialog(QDialog, FORM_CLASS):
    """Downloader for OSM data."""

    def __init__(self, parent=None, iface=None):
        """Constructor for import dialog.

        :param parent: Optional widget to use as parent
        :type parent: QWidget

        :param iface: An instance of QGisInterface
        :type iface: QGisInterface
        """
        QDialog.__init__(self, parent)
        self.parent = parent
        self.setupUi(self)

        self.setWindowTitle(self.tr('InaSAFE OpenStreetMap Downloader'))

        self.iface = iface

        self.help_context = 'openstreetmap_downloader'
        # creating progress dialog for download
        self.progress_dialog = QProgressDialog(self)
        self.progress_dialog.setAutoClose(False)
        title = self.tr('InaSAFE OpenStreetMap Downloader')
        self.progress_dialog.setWindowTitle(title)
        # Set up context help
        self.help_button = self.button_box.button(QtGui.QDialogButtonBox.Help)
        # Allow toggling the help button
        self.help_button.setCheckable(True)
        self.help_button.toggled.connect(self.help_toggled)
        self.stacked_widget.setCurrentIndex(1)
        # Disable boundaries group box until boundary checkbox is ticked
        self.boundary_group.setEnabled(False)

        # set up the validator for the file name prefix
        expression = QRegExp('^[A-Za-z0-9-_]*$')
        validator = QRegExpValidator(expression, self.filename_prefix)
        self.filename_prefix.setValidator(validator)

        self.restore_state()

        # Setup the rectangle map tool
        self.canvas = iface.mapCanvas()
        self.rectangle_map_tool = \
            RectangleMapTool(self.canvas)
        self.rectangle_map_tool.rectangle_created.connect(
            self.update_extent_from_rectangle)
        self.capture_button.clicked.connect(
            self.drag_rectangle_on_map_canvas)

        # Setup pan tool
        self.pan_tool = QgsMapToolPan(self.canvas)
        self.canvas.setMapTool(self.pan_tool)

        # Setup helper for admin_level
        json_file_path = resources_path('osm', 'admin_level_per_country.json')
        if os.path.isfile(json_file_path):
            self.countries = json.load(open(json_file_path))
            self.bbox_countries = None
            self.populate_countries()
            # connect
            self.country_comboBox.currentIndexChanged.connect(
                self.update_helper_political_level)
            self.admin_level_comboBox.currentIndexChanged.connect(
                self.update_helper_political_level)

        self.update_extent_from_map_canvas()

    def update_helper_political_level(self):
        """To update the helper about the country and the admin_level."""
        current_country = self.country_comboBox.currentText()
        index = self.admin_level_comboBox.currentIndex()
        current_level = self.admin_level_comboBox.itemData(index)
        content = None
        try:
            content = \
                self.countries[current_country]['levels'][str(current_level)]
            if content == 'N/A' or content == 'fixme' or content == '':
                raise KeyError
        except KeyError:
            content = self.tr('undefined')
        finally:
            text = self.tr('which represents %s in') % (content)
            self.boundary_helper.setText(text)

    def populate_countries(self):
        """Populate the combobox about countries and levels."""
        for i in range(1, 12):
            self.admin_level_comboBox.addItem(self.tr("Level %s" % i), i)

        # Set current index to admin_level 8, the most common one
        self.admin_level_comboBox.setCurrentIndex(7)

        list_countries = self.countries.keys()
        list_countries.sort()
        for country in list_countries:
            self.country_comboBox.addItem(country)

        self.bbox_countries = {}
#.........这里部分代码省略.........

class OsmDownloaderDialog(QDialog, FORM_CLASS):
    """Downloader for OSM data."""

    def __init__(self, parent=None, iface=None):
        """Constructor for import dialog.

        :param parent: Optional widget to use as parent
        :type parent: QWidget

        :param iface: An instance of QGisInterface
        :type iface: QGisInterface
        """
        QDialog.__init__(self, parent)
        self.parent = parent
        self.setupUi(self)

        self.setWindowTitle(self.tr('InaSAFE OpenStreetMap Downloader'))

        self.iface = iface
        self.buildings_url = 'http://osm.linfiniti.com/buildings-shp'
        self.building_points_url = \
            'http://osm.linfiniti.com/building-points-shp'
        self.roads_url = 'http://osm.linfiniti.com/roads-shp'

        self.help_context = 'openstreetmap_downloader'
        # creating progress dialog for download
        self.progress_dialog = QProgressDialog(self)
        self.progress_dialog.setAutoClose(False)
        title = self.tr('InaSAFE OpenStreetMap Downloader')
        self.progress_dialog.setWindowTitle(title)
        # Set up context help
        help_button = self.button_box.button(QtGui.QDialogButtonBox.Help)
        help_button.clicked.connect(self.show_help)

        self.show_info()

        # set up the validator for the file name prefix
        expression = QRegExp('^[A-Za-z0-9-_]*$')
        validator = QRegExpValidator(expression, self.filename_prefix)
        self.filename_prefix.setValidator(validator)

        # Set Proxy in webpage
        proxy = get_proxy()
        self.network_manager = QNetworkAccessManager(self)
        if proxy is not None:
            self.network_manager.setProxy(proxy)
        self.restore_state()

        # Setup the rectangle map tool
        self.canvas = iface.mapCanvas()
        self.rectangle_map_tool = \
            RectangleMapTool(self.canvas)
        self.rectangle_map_tool.rectangle_created.connect(
            self.update_extent_from_rectangle)
        self.button_extent_rectangle.clicked.connect(
            self.drag_rectangle_on_map_canvas)

        # Setup pan tool
        self.pan_tool = QgsMapToolPan(self.canvas)
        self.canvas.setMapTool(self.pan_tool)
        self.update_extent_from_map_canvas()

    def show_info(self):
        """Show usage info to the user."""
        # Read the header and footer html snippets
        header = html_header()
        footer = html_footer()

        string = header

        heading = m.Heading(self.tr('OSM Downloader'), **INFO_STYLE)
        body = self.tr(
            'This tool will fetch building (\'structure\') or road ('
            '\'highway\') data from the OpenStreetMap project for you. '
            'The downloaded data will have InaSAFE keywords defined and a '
            'default QGIS style applied. To use this tool effectively:'
        )
        tips = m.BulletedList()
        tips.add(self.tr(
            'Your current extent, when opening this window, will be used to '
            'determine the area for which you want data to be retrieved.'
            'You can interactively select the area by using the '
            '\'select on map\' button - which will temporarily hide this '
            'window and allow you to drag a rectangle on the map. After you '
            'have finished dragging the rectangle, this window will '
            'reappear.'))
        tips.add(self.tr(
            'Check the output directory is correct. Note that the saved '
            'dataset will be called either roads.shp or buildings.shp (and '
            'associated files).'
        ))
        tips.add(self.tr(
            'By default simple file names will be used (e.g. roads.shp, '
            'buildings.shp). If you wish you can specify a prefix to '
            'add in front of this default name. For example using a prefix '
            'of \'padang-\' will cause the downloaded files to be saved as '
            '\'padang-roads.shp\' and \'padang-buildings.shp\'. Note that '
            'the only allowed prefix characters are A-Z, a-z, 0-9 and the '
            'characters \'-\' and \'_\'. You can leave this blank if you '
            'prefer.'
#.........这里部分代码省略.........

    def __init__(self, iface, parent=None, extent=None, crs=None):
        """Constructor for the dialog.

        :param iface: A Quantum GIS QGisAppInterface instance.
        :type iface: QGisAppInterface

        :param parent: Parent widget of this dialog
        :type parent: QWidget

        :param extent: Extent of the user's preferred analysis area.
        :type extent: QgsRectangle

        :param crs: Coordinate reference system for user defined analysis
            extent.
        :type crs: QgsCoordinateReferenceSystem
        """
        QDialog.__init__(self, parent)
        self.setupUi(self)

        self.iface = iface
        self.parent = parent
        self.canvas = iface.mapCanvas()
        self.previous_map_tool = None
        self.show_info()
        # Prepare the map tool
        self.tool = RectangleMapTool(self.canvas)
        self.previous_map_tool = self.canvas.mapTool()

        if extent is None and crs is None:
            # Use the current map canvas extents as a starting point
            self.tool.set_rectangle(self.canvas.extent())
        else:
            # Ensure supplied extent is in current canvas crs
            transform = QgsCoordinateTransform(
                crs,
                self.canvas.mapRenderer().destinationCrs())
            transformed_extent = transform.transformBoundingBox(extent)
            self.tool.set_rectangle(transformed_extent)

        self._populate_coordinates()

        # Observe inputs for changes
        self.x_minimum.valueChanged.connect(self._coordinates_changed)
        self.y_minimum.valueChanged.connect(self._coordinates_changed)
        self.x_maximum.valueChanged.connect(self._coordinates_changed)
        self.y_maximum.valueChanged.connect(self._coordinates_changed)

        # Draw the rubberband
        self._coordinates_changed()

        # Wire up button events
        self.capture_button.clicked.connect(self.start_capture)
        # Handle cancel
        cancel_button = self.button_box.button(QtGui.QDialogButtonBox.Cancel)
        cancel_button.clicked.connect(self.reject)
        # Make sure to reshow this dialog when rectangle is captured
        self.tool.rectangle_created.connect(self.stop_capture)
        # Setup ok button
        self.ok_button = self.button_box.button(QtGui.QDialogButtonBox.Ok)
        self.ok_button.clicked.connect(self.accept)
        # Set up context help
        self.help_context = 'user_extents'
        help_button = self.button_box.button(QtGui.QDialogButtonBox.Help)
        help_button.clicked.connect(self.show_help)
        # Reset / Clear button
        clear_button = self.button_box.button(QtGui.QDialogButtonBox.Reset)
        clear_button.setText(self.tr('Clear'))
        clear_button.clicked.connect(self.clear)

        # Populate the bookmarks list and connect the combobox
        self._populate_bookmarks_list()
        self.comboBox_bookmarks_list.currentIndexChanged.connect(
            self.bookmarks_index_changed)

class ExtentSelectorDialog(QDialog, FORM_CLASS):
    """Dialog for letting user determine analysis extents.
    """

    extent_defined = pyqtSignal(QgsRectangle, QgsCoordinateReferenceSystem)
    clear_extent = pyqtSignal()
    extent_selector_closed = pyqtSignal()

    def __init__(self, iface, parent=None, extent=None, crs=None):
        """Constructor for the dialog.

        :param iface: A Quantum GIS QGisAppInterface instance.
        :type iface: QGisAppInterface

        :param parent: Parent widget of this dialog
        :type parent: QWidget

        :param extent: Extent of the user's preferred analysis area.
        :type extent: QgsRectangle

        :param crs: Coordinate reference system for user defined analysis
            extent.
        :type crs: QgsCoordinateReferenceSystem
        """
        QDialog.__init__(self, parent)
        self.setupUi(self)

        self.iface = iface
        self.parent = parent
        self.canvas = iface.mapCanvas()
        self.previous_map_tool = None
        self.show_info()
        # Prepare the map tool
        self.tool = RectangleMapTool(self.canvas)
        self.previous_map_tool = self.canvas.mapTool()

        if extent is None and crs is None:
            # Use the current map canvas extents as a starting point
            self.tool.set_rectangle(self.canvas.extent())
        else:
            # Ensure supplied extent is in current canvas crs
            transform = QgsCoordinateTransform(
                crs,
                self.canvas.mapRenderer().destinationCrs())
            transformed_extent = transform.transformBoundingBox(extent)
            self.tool.set_rectangle(transformed_extent)

        self._populate_coordinates()

        # Observe inputs for changes
        self.x_minimum.valueChanged.connect(self._coordinates_changed)
        self.y_minimum.valueChanged.connect(self._coordinates_changed)
        self.x_maximum.valueChanged.connect(self._coordinates_changed)
        self.y_maximum.valueChanged.connect(self._coordinates_changed)

        # Draw the rubberband
        self._coordinates_changed()

        # Wire up button events
        self.capture_button.clicked.connect(self.start_capture)
        # Handle cancel
        cancel_button = self.button_box.button(QtGui.QDialogButtonBox.Cancel)
        cancel_button.clicked.connect(self.reject)
        # Make sure to reshow this dialog when rectangle is captured
        self.tool.rectangle_created.connect(self.stop_capture)
        # Setup ok button
        self.ok_button = self.button_box.button(QtGui.QDialogButtonBox.Ok)
        self.ok_button.clicked.connect(self.accept)
        # Set up context help
        self.help_context = 'user_extents'
        help_button = self.button_box.button(QtGui.QDialogButtonBox.Help)
        help_button.clicked.connect(self.show_help)
        # Reset / Clear button
        clear_button = self.button_box.button(QtGui.QDialogButtonBox.Reset)
        clear_button.setText(self.tr('Clear'))
        clear_button.clicked.connect(self.clear)

        # Populate the bookmarks list and connect the combobox
        self._populate_bookmarks_list()
        self.comboBox_bookmarks_list.currentIndexChanged.connect(
            self.bookmarks_index_changed)

    def show_help(self):
        """Load the help text for the dialog."""
        show_context_help(self.help_context)

    def show_info(self):
        """Show usage info to the user."""
        # Read the header and footer html snippets
        header = html_header()
        footer = html_footer()

        string = header

        heading = m.Heading(self.tr('User Extents Tool'), **INFO_STYLE)
        body = self.tr(
            'This tool allows you to specify exactly which geographical '
            'region should be used for your analysis. You can either '
            'enter the coordinates directly into the input boxes below '
            '(using the same CRS as the canvas is currently set to), or '
#.........这里部分代码省略.........

class ExtentSelectorDialog(QDialog, FORM_CLASS):
    """Dialog for letting user determine analysis extents.
    """

    extent_defined = pyqtSignal(QgsRectangle, QgsCoordinateReferenceSystem)
    clear_extent = pyqtSignal()
    extent_selector_closed = pyqtSignal()

    def __init__(self, iface, parent=None, extent=None, crs=None):
        """Constructor for the dialog.

        :param iface: A Quantum GIS QGisAppInterface instance.
        :type iface: QGisAppInterface

        :param parent: Parent widget of this dialog
        :type parent: QWidget

        :param extent: Extent of the user's preferred analysis area.
        :type extent: QgsRectangle

        :param crs: Coordinate reference system for user defined analysis
            extent.
        :type crs: QgsCoordinateReferenceSystem
        """
        QDialog.__init__(self, parent)
        self.setupUi(self)

        self.iface = iface
        self.parent = parent
        self.canvas = iface.mapCanvas()
        self.previous_map_tool = None
        self.show_info()
        # Prepare the map tool
        self.tool = RectangleMapTool(self.canvas)
        self.previous_map_tool = self.canvas.mapTool()

        if extent is None and crs is None:
            # Use the current map canvas extents as a starting point
            self.tool.set_rectangle(self.canvas.extent())
        else:
            # Ensure supplied extent is in current canvas crs
            transform = QgsCoordinateTransform(
                crs,
                self.canvas.mapRenderer().destinationCrs())
            transformed_extent = transform.transformBoundingBox(extent)
            self.tool.set_rectangle(transformed_extent)

        self._populate_coordinates()

        # Observe inputs for changes
        self.x_minimum.valueChanged.connect(self._coordinates_changed)
        self.y_minimum.valueChanged.connect(self._coordinates_changed)
        self.x_maximum.valueChanged.connect(self._coordinates_changed)
        self.y_maximum.valueChanged.connect(self._coordinates_changed)

        # Draw the rubberband
        self._coordinates_changed()

        # Wire up button events
        self.capture_button.clicked.connect(self.start_capture)
        # Handle cancel
        cancel_button = self.button_box.button(QtGui.QDialogButtonBox.Cancel)
        cancel_button.clicked.connect(self.reject)
        # Make sure to reshow this dialog when rectangle is captured
        self.tool.rectangle_created.connect(self.stop_capture)
        # Setup ok button
        ok_button = self.button_box.button(QtGui.QDialogButtonBox.Ok)
        ok_button.clicked.connect(self.accept)
        # Set up context help
        self.help_context = 'user_extents'
        help_button = self.button_box.button(QtGui.QDialogButtonBox.Help)
        help_button.clicked.connect(self.show_help)
        # Reset / Clear button
        clear_button = self.button_box.button(QtGui.QDialogButtonBox.Reset)
        clear_button.setText(self.tr('Clear'))
        clear_button.clicked.connect(self.clear)

    def show_help(self):
        """Load the help text for the dialog."""
        show_context_help(self.help_context)

    def show_info(self):
        """Show usage info to the user."""
        # Read the header and footer html snippets
        header = html_header()
        footer = html_footer()

        string = header

        heading = m.Heading(self.tr('User Extents Tool'), **INFO_STYLE)
        body = self.tr(
            'This tool allows you to specify exactly which geographical '
            'region should be used for your analysis. You can either '
            'enter the coordinates directly into the input boxes below '
            '(using the same CRS as the canvas is currently set to), or '
            'you can interactively select the area by using the \'select '
            'on map\' button - which will temporarily hide this window and '
            'allow you to drag a rectangle on the map. After you have '
            'finished dragging the rectangle, this window will reappear. '
            'If you enable the \'Toggle scenario outlines\' tool on the '
#.........这里部分代码省略.........

    def __init__(self, iface, parent=None, extent=None, crs=None):
        """Constructor for the dialog.

        :param iface: A Quantum GIS QgisAppInterface instance.
        :type iface: QgisAppInterface

        :param parent: Parent widget of this dialog.
        :type parent: QWidget

        :param extent: Extent of the user's preferred analysis area.
        :type extent: QgsRectangle

        :param crs: CRS for user defined analysis extent.
        :type crs: QgsCoordinateReferenceSystem
        """
        QDialog.__init__(self, parent)
        self.setupUi(self)

        icon = resources_path('img', 'icons', 'set-extents-tool.svg')
        self.setWindowIcon(QIcon(icon))

        self.iface = iface
        self.parent = parent
        self.canvas = iface.mapCanvas()
        self.previous_map_tool = None
        # Prepare the map tool
        self.tool = RectangleMapTool(self.canvas)
        self.previous_map_tool = self.canvas.mapTool()

        if extent is None:
            # Use the current map canvas extents as a starting point
            self.tool.set_rectangle(self.canvas.extent())
        else:

            if isinstance(extent, QgsGeometry):
                # In InaSAFE V4, the extent is a QgsGeometry.
                # This like a hack to transform a geometry to a rectangle.
                extent = wkt_to_rectangle(extent.asWkt())

            # Ensure supplied extent is in current canvas crs
            transform = QgsCoordinateTransform(
                crs,
                self.canvas.mapSettings().destinationCrs(),
                QgsProject.instance()
            )
            transformed_extent = transform.transformBoundingBox(extent)
            self.tool.set_rectangle(transformed_extent)

        self._populate_coordinates()

        # Observe inputs for changes
        self.x_minimum.valueChanged.connect(self._coordinates_changed)
        self.y_minimum.valueChanged.connect(self._coordinates_changed)
        self.x_maximum.valueChanged.connect(self._coordinates_changed)
        self.y_maximum.valueChanged.connect(self._coordinates_changed)

        # Draw the rubberband
        self._coordinates_changed()

        # Wire up button events
        self.capture_button.clicked.connect(self.start_capture)
        # Handle cancel
        cancel_button = self.button_box.button(
            QtWidgets.QDialogButtonBox.Cancel)
        cancel_button.clicked.connect(self.reject)
        # Make sure to reshow this dialog when rectangle is captured
        self.tool.rectangle_created.connect(self.stop_capture)
        # Setup ok button
        self.ok_button = self.button_box.button(QtWidgets.QDialogButtonBox.Ok)
        self.ok_button.clicked.connect(self.accept)
        # Set up context help
        self.help_button = self.button_box.button(
            QtWidgets.QDialogButtonBox.Help)
        # Allow toggling the help button
        self.help_button.setCheckable(True)
        self.help_button.toggled.connect(self.help_toggled)
        self.main_stacked_widget.setCurrentIndex(1)
        # Reset / Clear button
        clear_button = self.button_box.button(QtWidgets.QDialogButtonBox.Reset)
        clear_button.setText(self.tr('Clear'))
        clear_button.clicked.connect(self.clear)

        # Populate the bookmarks list and connect the combobox
        self._populate_bookmarks_list()
        self.bookmarks_list.currentIndexChanged.connect(
            self.bookmarks_index_changed)

        # Reinstate the last used radio button
        mode = setting('analysis_extents_mode', HAZARD_EXPOSURE_VIEW)

        if mode == HAZARD_EXPOSURE_VIEW:
            self.hazard_exposure_view_extent.setChecked(True)
        elif mode == EXPOSURE:
            self.exposure_only.setChecked(True)
        elif mode == HAZARD_EXPOSURE:
            self.hazard_exposure_only.setChecked(True)
        elif mode == HAZARD_EXPOSURE_BOOKMARK:
            self.hazard_exposure_bookmark.setChecked(True)
        elif mode == HAZARD_EXPOSURE_BOUNDINGBOX:
            self.hazard_exposure_user_extent.setChecked(True)
#.........这里部分代码省略.........