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PyQt mouse events for QGraphicsView

I am trying to get the coordinates of various mouse events from QGraphicsView, but I cannot figure out how to fire them. In the end, I want to add an image to the GUI and then draw on top of it.

Ideally, I would like the coordinates to have a beginning in the upper left corner

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test.py

 import sys from PyQt4 import QtCore, QtGui, uic class test(QtGui.QMainWindow): def __init__(self): QtGui.QMainWindow.__init__(self) self.ui = uic.loadUi('test.ui', self) self.connect(self.ui.graphicsView, QtCore.SIGNAL("mousePressEvent()"), self.mouse_pressed) self.connect(self.ui.graphicsView, QtCore.SIGNAL("mouseMoveEvent()"), self.mouse_moved) self.connect(self.ui.graphicsView, QtCore.SIGNAL("mouseReleaseEvent()"), self.mouse_released) self.ui.show() def mouse_pressed(self): p = QtGui.QCursor.pos() print "pressed here: " + px() + ", " + py() def mouse_moved(self): p = QtGui.QCursor.pos() print "moved here: " + px() + ", " + py() def mouse_released(self): p = QtGui.QCursor.pos() print "released here: " + px() + ", " + py() def main(): app = QtGui.QApplication(sys.argv) ui = test() sys.exit(app.exec_()) if __name__ == '__main__': main()

test.ui

 <?xml version="1.0" encoding="UTF-8"?> <ui version="4.0"> <class>MainWindow</class> <widget class="QMainWindow" name="MainWindow"> <property name="geometry"> <rect> <x>0</x> <y>0</y> <width>800</width> <height>600</height> </rect> </property> <property name="windowTitle"> <string>MainWindow</string> </property> <widget class="QWidget" name="centralwidget"> <layout class="QVBoxLayout" name="verticalLayout"> <item> <widget class="QGraphicsView" name="graphicsView"/> </item> </layout> </widget> <widget class="QMenuBar" name="menubar"> <property name="geometry"> <rect> <x>0</x> <y>0</y> <width>800</width> <height>22</height> </rect> </property> </widget> <widget class="QStatusBar" name="statusbar"/> </widget> <resources/> <connections/> </ui>

EDIT:

It looks like it works. the ellipse no longer moves as the click event seems to be capturing. any ideas?

 import sys from PyQt4 import QtCore, QtGui, uic class graphicsScene(QtGui.QGraphicsScene): def __init__ (self, parent=None): super(graphicsScene, self).__init__ (parent) def mousePressEvent(self, event): position = QtCore.QPointF(event.scenePos()) print "pressed here: " + str(position.x()) + ", " + str(position.y()) self.update() def mouseMoveEvent(self, event): position = QtCore.QPointF(event.scenePos()) print "moved here: " + str(position.x()) + ", " + str(position.y()) self.update() def mouseReleaseEvent(self, event): position = QtCore.QPointF(event.scenePos()) print "released here: " + str(position.x()) + ", " + str(position.y()) self.update() class test(QtGui.QMainWindow): def __init__(self): QtGui.QMainWindow.__init__(self) self.ui = uic.loadUi('test.ui', self) self.scene = graphicsScene() self.ui.graphicsView.setScene(self.scene) pen = QtGui.QPen(QtCore.Qt.red) brush = QtGui.QBrush(QtCore.Qt.blue) e = self.scene.addEllipse(10,10,100,100, pen, brush) e.setFlag(QtGui.QGraphicsItem.ItemIsMovable, True) self.ui.show() def main(): app = QtGui.QApplication(sys.argv) ui = test() sys.exit(app.exec_()) if __name__ == '__main__': main()
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2 answers

mousePressEvent and other methods are not slots. You cannot use connect for these methods. You need to set the event filter in your viewport() view and catch the events in your eventFilter widget eventFilter .

See Event Filters .

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To keep the ellipse moving, you need to pass the event to the parent. For example, for mouseMoveEvent, at the end of the method you need to add this line:

 super(graphicsScene, self).mouseMoveEvent(event)
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Source: https://habr.com/ru/post/1493764/

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