class MoveLandmarkTool(QgsMapTool):
def __init__(self, canvas):
super().__init__(canvas)
self.lm_layer = None
self.lm_point = None
self.clicked_on_landmark = False
self.band = None
def set_landmark_layer(self, layer):
"""Sets current land mark layer"""
self.lm_layer = layer
def canvasPressEvent(self, event):
"""
If pressEvent point is near the layer point, enable dragging. Else show msg box
"""
if event.button() == Qt.LeftButton:
click_point = self.toLayerCoordinates(self.lm_layer, event.pos())
if self.lm_layer.featureCount() == 1:
feature_list = self.lm_layer.dataProvider().getFeatures(
) #Returns iterator to a list of one feature
self.lm_feature = next(
feature_list) #get first and only element in the list
self.lm_point = self.lm_feature.geometry().asPoint()
dist = QgsPointXY.distance(click_point, self.lm_point)
tolerance = (QgsTolerance.toleranceInMapUnits(
15, self.lm_layer,
self.canvas().mapSettings(), QgsTolerance.Pixels))
if dist < tolerance:
#Clicked on a landmark
self.clicked_on_landmark = True
self.create_ghost_point()
else:
#Not clicked on a landmark
confirmation_msg = "Do you want to move {} here? \n\n".format(
self.lm_layer.name())
reply = QMessageBox.question(self.parent(),
'Movement Confirmation',
confirmation_msg,
QMessageBox.Yes,
QMessageBox.No)
if reply == QMessageBox.Yes:
self.move_position(click_point)
def canvasReleaseEvent(self, event):
"""
If dragging, stop and move landmark position to the release event point
Also destroy rubberband (ghost point)
"""
if (event.button() == Qt.LeftButton and self.lm_layer
and self.clicked_on_landmark):
release_point = self.toLayerCoordinates(self.lm_layer, event.pos())
self.move_position(release_point)
self.clicked_on_landmark = False
if self.band:
self.band.hide()
self.band = None
def move_position(self, end_point):
"""
Translates landmark layer to end_point
:param end_point: Where to move the landmark point
"""
# If layer is not stored in memory, change its datasource to memory
if self.lm_layer.source()[0] == "/":
temp_feature = next(self.lm_layer.dataProvider().getFeatures()
) # iterator with only 1 feature in list
options = QgsDataProvider.ProviderOptions()
self.lm_layer.setDataSource("Point?crs=epsg:4326",
self.lm_layer.name(), "memory",
options)
self.lm_layer.dataProvider().addFeatures([temp_feature])
self.lm_feature = next(self.lm_layer.dataProvider().getFeatures())
dx = end_point.x() - self.lm_point.x()
dy = end_point.y() - self.lm_point.y()
self.lm_layer.startEditing()
self.lm_layer.translateFeature(self.lm_feature.id(), dx, dy)
self.lm_layer.commitChanges()
def create_ghost_point(self):
"""
Creates rubber band as a ghost image of the landmark point
"""
if self.band is not None:
self.band.hide()
self.band = None
self.band = QgsRubberBand(self.canvas())
self.band.setColor(QColor("green"))
self.band.setToGeometry(self.lm_feature.geometry(), self.lm_layer)
self.band.show()
def canvasMoveEvent(self, event):
"""
If dragging, move ghost point
"""
if self.clicked_on_landmark:
point = self.toLayerCoordinates(self.lm_layer, event.pos())
self.move_ghost_point(point)
def move_ghost_point(self, point):
"""
Translates ghost point to point
:param point: where the rubber band is going to be translated
"""
if self.band:
offset_x = point.x() - self.lm_point.x()
offset_y = point.y() - self.lm_point.y()
self.band.setTranslationOffset(offset_x, offset_y)
self.band.updatePosition()
self.band.update()
