class PointTool(QgsMapTool):

def __init__(self, canvas):
    QgsMapTool.__init__(self, canvas)
    self.canvas = canvas

def canvasReleaseEvent(self, event):
    """ Checks which click was used : if left, triggers the pan action, else, adds point. """

    if event.button() == QtCore.Qt.RightButton:
        # The right click triggers the point selection
        x = event.pos().x()
        y = event.pos().y()
        self.clickedPoint = self.canvas.getCoordinateTransform().toMapCoordinates(x, y)
        self.showPoint(self.clickedPoint)
        self.canvas.refresh()

    elif event.button() == QtCore.Qt.LeftButton:
        print("release clicked left")
        # The left click triggers the pan action
        iface.actionPan().trigger()

def showPoint(self, point):
    """ Adds point in qgis main window """

    # Using a vertex marker to show the selected point as a red cross
    m = QgsVertexMarker(self.canvas)
    m.setCenter(point)
    m.setColor(QColor(255,0,0))
    m.setIconSize(10)
    m.setIconType(QgsVertexMarker.ICON_X)

    self.canvas.refresh()