magic_wand.py

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

from qgis.PyQt.QtCore import QSettings, QTranslator, QCoreApplication, Qt, QSize
from qgis.PyQt.QtGui import QIcon, QImage, QPainter
from qgis.PyQt.QtWidgets import QAction, QMessageBox
from qgis.core import QgsProject, QgsMapLayer, QgsRectangle, QgsPoint, QgsMultiBandColorRenderer, QgsRaster, QgsMapSettings, QgsMapRendererCustomPainterJob
# Initialize Qt resources from file resources.py
from .resources import *

# Import the code for the DockWidget
from .magic_wand_dockwidget import MagicwandDockWidget
import os.path

from .Utils import ClickTool
from .image_analyzer import ImageAnalyzer
from .polygon_maker import PolygonMaker


class Magicwand:
    """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

        self.canvas = iface.mapCanvas()

        # 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',
            'Magicwand_{}.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 = self.tr(u'&Magic Wand')
        # TODO: We are going to let the user set this up in a future iteration
        self.toolbar = self.iface.addToolBar(u'Magicwand')
        self.toolbar.setObjectName(u'Magicwand')

        #print "** INITIALIZING Magicwand"

        self.pluginIsActive = False
        self.dockwidget = None

        self.output_layer = 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('Magicwand', 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)
        text = "Magic Wand"
        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.addPluginToVectorMenu(
                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/magic_wand/icon.png'
        self.add_action(
            icon_path,
            text=self.tr(u''),
            callback=self.run,
            parent=self.iface.mainWindow())

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

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

        #print "** CLOSING Magicwand"

        # 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 crashe
        # when closing the docked window:
        # self.dockwidget = None

        self.pluginIsActive = False


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

        #print "** UNLOAD Magicwand"

        for action in self.actions:
            self.iface.removePluginVectorMenu(
                self.tr(u'&Magic Wand'),
                action)
            self.iface.removeToolBarIcon(action)
        # remove the toolbar
        del self.toolbar

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

    #actions on mapcanvas clicked
    def click_action(self, point):
        mapSettings = self.iface.mapCanvas().mapSettings()
        image = self.make_image(mapSettings)
        image_analyzer = ImageAnalyzer(image)
        #get slider value
        resize_multiply = self.dockwidget.accuracy_slider.value() / 100
        threshold = 100 - self.dockwidget.threshold_slider.value()
        bin_index = image_analyzer.to_binary(point, resize_multiply, threshold)

        polygon_maker = PolygonMaker(self.iface.mapCanvas(), bin_index)
        project_crs = QgsProject.instance().crs()
        single_mode = self.dockwidget.single_mode.isChecked()
        selected_layer_id = self.dockwidget.layerComboBox.currentData()

        polygon_maker.make_polygons(point, crs=project_crs, single_mode=single_mode, layer_id=selected_layer_id)

        selected_index = self.dockwidget.layerComboBox.currentIndex()
        self.reload_combo_box()
        self.dockwidget.layerComboBox.setCurrentIndex(selected_index)
        self.canvas.refreshAllLayers()
        
        return

    #make and return QImage from MapCanvas
    def make_image(self, mapSettings):
        image = QImage(mapSettings.outputSize(), QImage.Format_RGB32)
        p = QPainter()
        p.begin(image)
        mapRenderer = QgsMapRendererCustomPainterJob(mapSettings, p)
        mapRenderer.start()
        mapRenderer.waitForFinished()
        p.end()
        return image

    def enable_magicwand(self):
        ct = ClickTool(self.iface,  self.click_action)
        self.previous_map_tool = self.iface.mapCanvas().mapTool()
        self.iface.mapCanvas().setMapTool(ct)

    def init_sliders(self):
        self.dockwidget.accuracy_slider.setMinimum(20)
        self.dockwidget.accuracy_slider.setMaximum(100)
        self.dockwidget.accuracy_slider.setSingleStep(20)
        self.dockwidget.accuracy_slider.setValue(60)
        
        self.dockwidget.threshold_slider.setMinimum(10)
        self.dockwidget.threshold_slider.setMaximum(90)
        self.dockwidget.threshold_slider.setSingleStep(10)
        self.dockwidget.threshold_slider.setValue(50)

    def reload_combo_box(self):
        self.dockwidget.layerComboBox.clear()
        self.dockwidget.layerComboBox.addItem('===New Layer===',0)
        layers = QgsProject.instance().mapLayers()
        for key, layer in layers.items():
            if layer.type() == QgsMapLayer.VectorLayer:
                #key is ID of each layers
                self.dockwidget.layerComboBox.addItem(layer.name(),key)

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

        if not self.pluginIsActive:
            self.pluginIsActive = True

            #print "** STARTING Magicwand"

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

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

            # show the dockwidget
            self.iface.addDockWidget(Qt.TopDockWidgetArea, self.dockwidget)
            self.dockwidget.show()

            ct = ClickTool(self.iface,  self.click_action)
            self.previous_map_tool = self.iface.mapCanvas().mapTool()
            self.iface.mapCanvas().setMapTool(ct)

            self.dockwidget.enable_button.clicked.connect(self.enable_magicwand)

            QgsProject.instance().layersAdded.connect(self.reload_combo_box)
            QgsProject.instance().layersRemoved.connect(self.reload_combo_box)
            self.reload_combo_box()
            self.init_sliders()