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',
'PolygonSimplifier_{}.qm'.format(locale))
if os.path.exists(locale_path):
self.translator = QTranslator()
self.translator.load(locale_path)
if qVersion() > '4.3.3':
QCoreApplication.installTranslator(self.translator)
# Create the dialog (after translation) and keep reference
self.dlg = PolygonSimplifierDialog(self.iface)
# Declare instance attributes
self.actions = []
self.menu = self.tr(u'&PolygonSimplifier')
# TODO: We are going to let the user set this up in a future iteration
self.toolbar = self.iface.addToolBar(u'PolygonSimplifier')
self.toolbar.setObjectName(u'PolygonSimplifier')
class PolygonSimplifier:
"""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',
'PolygonSimplifier_{}.qm'.format(locale))
if os.path.exists(locale_path):
self.translator = QTranslator()
self.translator.load(locale_path)
if qVersion() > '4.3.3':
QCoreApplication.installTranslator(self.translator)
# Create the dialog (after translation) and keep reference
self.dlg = PolygonSimplifierDialog(self.iface)
# Declare instance attributes
self.actions = []
self.menu = self.tr(u'&PolygonSimplifier')
# TODO: We are going to let the user set this up in a future iteration
self.toolbar = self.iface.addToolBar(u'PolygonSimplifier')
self.toolbar.setObjectName(u'PolygonSimplifier')
# 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('PolygonSimplifier', 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.addPluginToMenu(
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/PolygonSimplifier/icon.png'
self.add_action(
icon_path,
text=self.tr(u'Simplify polygons'),
callback=self.run,
parent=self.iface.mainWindow())
def unload(self):
"""Removes the plugin menu item and icon from QGIS GUI."""
for action in self.actions:
self.iface.removePluginMenu(
self.tr(u'&PolygonSimplifier'),
action)
self.iface.removeToolBarIcon(action)
# remove the toolbar
del self.toolbar
def run(self):
"""PolygonSimplifier entry point"""
layersLoaded = self.dlg.loadLayers(self.iface)
if not layersLoaded:
QMessageBox.warning(self.dlg, 'Warning', 'No polygon type vector layer is available.')
else:
self.dlg.show()
result = self.dlg.exec_()
# See if OK was pressed
if result:
# Read parameters from the dialog.
inputLayer = self.dlg.getSelectedLayer()
epsilon = self.dlg.epsilon.value()
minPolygonSize = self.dlg.minimumPolygonSize.value()
if self.dlg.algorithms.currentText() == "Ramer-Douglas-Peucker":
algorithm = RamerDouglasPeucker(self.dlg.epsilon.value())
elif self.dlg.algorithms.currentText() == "Visvalingam-Whyatt":
algorithm = VisvalingamWhyatt(self.dlg.epsilon.value())
elif self.dlg.algorithms.currentText() == "Whirlpool":
algorithm = Whirlpool(self.dlg.epsilon.value())
preserveTopology = self.dlg.preserveTopology.isChecked()
addResultToCanvas = self.dlg.addResultToCanvas.isChecked()
outputLayerPath = self.dlg.outputPath.text()
errorLayerPath = self.dlg.outputPath.text().replace('.shp', '_errors.shp')
# Run the generalization with the specified parameters.
algorithmRunner = SimplifierAlgorithmRunner(algorithm)
outputLayer, errorLayer = algorithmRunner.run(inputLayer, preserveTopology, minPolygonSize)
QgsVectorFileWriter.writeAsVectorFormat(outputLayer, outputLayerPath, inputLayer.dataProvider().encoding(), None)
if errorLayer.featureCount() > 0:
QgsVectorFileWriter.writeAsVectorFormat(errorLayer, errorLayerPath, inputLayer.dataProvider().encoding(), None)
if addResultToCanvas:
self.iface.addVectorLayer(outputLayerPath, "result", "ogr")
if errorLayer.featureCount() > 0:
self.iface.addVectorLayer(errorLayerPath, "errors", "ogr")
