Briefly I want to track mouse coordinate over a QGraphicsView.
This answer works well for a QLabel object, but not works as expected when I switch to QGraphicsView as follows:
from PyQt4 import QtGui, QtCore
class Window(QtGui.QWidget):
def __init__(self):
QtGui.QWidget.__init__(self)
self.graphicsView = QtGui.QGraphicsView(self)
self.graphicsView.setMouseTracking(True)
self.graphicsView.installEventFilter(self)
layout = QtGui.QVBoxLayout(self)
layout.addWidget(self.graphicsView)
def eventFilter(self, source, event):
if (event.type() == QtCore.QEvent.MouseMove and
source is self.graphicsView):
pos = event.pos()
print('mouse move: (%d, %d)' % (pos.x(), pos.y()))
return QtGui.QWidget.eventFilter(self, source, event)
if __name__ == '__main__':
import sys
app = QtGui.QApplication(sys.argv)
window = Window()
window.show()
window.resize(200, 100)
sys.exit(app.exec_())
Specifically, it seems like that the event is caught only when my cursor moves accross the border of the QGraphicsView (the black lines).
Could anyone tell me why and is there any better solutions?
For certain widgets, you need to use its viewport instead:
self.graphicsView.viewport().installEventFilter(self)
...
def eventFilter(self, source, event):
if (event.type() == QtCore.QEvent.MouseMove and
source is self.graphicsView.viewport()):
...
An alternative is to override mouseMoveEvent(event) of QGraphicsView directly.
Example:
from PySide import QtGui
class MyGraphicsView(QtGui.QGraphicsView):
def __init__(self, parent):
QtGui.QGraphicsView.__init__(self, parent)
self.setMouseTracking(True)
def mouseMoveEvent(self, event):
print('mouseMoveEvent: pos {}'.format(event.pos()))
class Window(QtGui.QWidget):
def __init__(self):
QtGui.QWidget.__init__(self)
self.graphicsView = MyGraphicsView(self)
layout = QtGui.QVBoxLayout(self)
layout.addWidget(self.graphicsView)
app = QtGui.QApplication([])
window = Window()
window.show()
window.resize(200, 100)
app.exec_()
Related
I want to get the position of mouse while it's hovering over a label. I read this but my problem is different. I need to grab the mouse position as it hovers over my label without clicking so, mouseMoveEvent doesn't help
here's my code:
class MyWindow(QMainWindow):
def __init__(self):
super().__init__()
self.WindowGUI()
self.level = "Image Not Loaded Yet"
self.mouseIsClicked = False
self.top = 90
self.left = 90
self.height = 1800
self.width = 1800
self.setGeometry(self.top, self.left, self.height, self.width)
self.setWindowTitle("Manual Contact Andgle")
self.setMouseTracking(True)
mainWidget = QWidget(self)
self.setCentralWidget(mainWidget)
mainWidget.setLayout(self.finalVbox)
self.show()
def WindowGUI(self):
self.finalVbox = QVBoxLayout() # Final Layout
self.mainHBox = QHBoxLayout() # Hbox for picLable and Buttons
self.mainVBox = QVBoxLayout() # VBox for two Groupboxes
self.lineVBox = QVBoxLayout() # VBox For Line Drawing Buttons
self.fileVBox = QVBoxLayout() # VBox for file Loading and Saving Buttons
self.lineGroupbox = QGroupBox("Drawing") # GroupBox For Line Drawing Buttons
self.fileGroupbox = QGroupBox("File") # GroupBox for File Loading and Saving Buttons
self.picLable = Label(self) # Lable For showing the Image
self.piclable_pixmap = QPixmap("loadImage.png") # Setting Pixmap
self.picLable.setPixmap(self.piclable_pixmap) # setting pixmap to piclable
def mouseMoveEvent(self, QMouseEvent):
print(QMouseEvent.pos())
If you want to detect the mouse position without pressing on the widget then you must enable mouseTracking that will make the mouseMoveEvent invoked when the mouse is pressed or not, if you want to verify that it is not pressed you must use the buttons() method:
import sys
from PyQt5 import QtWidgets
class Label(QtWidgets.QLabel):
def __init__(self, parent=None):
super().__init__(parent)
self.setMouseTracking(True)
def mouseMoveEvent(self, event):
if not event.buttons():
print(event.pos())
super().mouseMoveEvent(event)
if __name__ == "__main__":
app = QtWidgets.QApplication(sys.argv)
w = Label()
w.resize(640, 480)
w.show()
sys.exit(app.exec_())
UPDATE:
Mouse events are propagated from children to parents if the children do not consume it, that is, if the child consumes it then the parent cannot consume it. So the QLabel is consuming that event so the window will not be notified, so in this case an eventFilter should be used:
import sys
from PyQt5.QtCore import pyqtSignal, pyqtSlot, QEvent, QObject, QPoint
from PyQt5.QtGui import QPixmap
from PyQt5.QtWidgets import QApplication, QLabel, QMainWindow
class HoverTracker(QObject):
positionChanged = pyqtSignal(QPoint)
def __init__(self, widget):
super().__init__(widget)
self._widget = widget
self.widget.setMouseTracking(True)
self.widget.installEventFilter(self)
#property
def widget(self):
return self._widget
def eventFilter(self, obj, event):
if obj is self.widget and event.type() == QEvent.MouseMove:
self.positionChanged.emit(event.pos())
return super().eventFilter(obj, event)
class MyWindow(QMainWindow):
def __init__(self):
super().__init__()
self.setWindowTitle("Manual Contact Andgle")
self.picLable = QLabel(self)
self.picLable.setPixmap(QPixmap("loadImage.png"))
hover_tracker = HoverTracker(self.picLable)
hover_tracker.positionChanged.connect(self.on_position_changed)
#pyqtSlot(QPoint)
def on_position_changed(self, p):
print(p)
if __name__ == "__main__":
app = QApplication(sys.argv)
w = MyWindow()
w.resize(640, 480)
w.show()
sys.exit(app.exec_())
You can use enterEvent.
Enter event gets called everytime the mouse is over the widget. With the event.pos() you can get the mouse coordinates.
self.label.enterEvent = lambda event: print(event.pos())
How can I get the value returned from mousePressEvent of a widget and apply it to another widget?
Here's the widget with the mousePressEvent:
class Text(QTextEdit):
...
def mousePressEvent(self, event):
if event.button()==Qt.LeftButton:
return "test"
Now I want to use the string returned from the event and apply it to another widget:
class OtherWidget(QWidget):
...
self.label=QLabel()
self.label.setText(???) # <=== How to put the string here?
...
How can I do that? I have tried the following but it does not work.
self.label.setText(Text().mousePressEvent())
The events do not return anything for what you point out is impossible, Qt to send information asynchronously uses the signals, in the next part I show an example:
from PyQt5 import QtCore, QtWidgets
class Text(QtWidgets.QTextEdit):
mousePressSignal = QtCore.pyqtSignal(str)
def mousePressEvent(self, event):
if event.button() == QtCore.Qt.LeftButton:
text = "test: {}-{}".format(event.pos().x(), event.pos().y())
self.mousePressSignal.emit(text)
class OtherWidget(QtWidgets.QWidget):
def __init__(self, parent=None):
super(OtherWidget, self).__init__(parent)
self.label = QtWidgets.QLabel()
lay = QtWidgets.QVBoxLayout(self)
lay.addWidget(self.label, alignment=QtCore.Qt.AlignCenter)
#QtCore.pyqtSlot(str)
def setText(self, text):
self.label.setText(text)
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
t = Text()
o = OtherWidget()
o.resize(640, 480)
t.mousePressSignal.connect(o.setText)
t.show()
o.show()
sys.exit(app.exec_())
class widget(QWidget):
...
self.edit=QTextEdit()
def mousePressEvent(self, event):
if event.button()==Qt.LeftButton:
print('test')
self.edit.mousePressEvent(event)
I have tried that but it does not work. It works for the parent widget. Is there anyway I can do it without subclassing the QTextEdit?
In this case you must use an eventFilter in addition to the classes that inherit from QAbstractScrollArea as QTextEdit you must use the viewport():
from PyQt5 import QtCore, QtWidgets
class Widget(QtWidgets.QWidget):
def __init__(self, parent=None):
super(Widget, self).__init__(parent)
self.edit = QtWidgets.QTextEdit()
btn = QtWidgets.QPushButton()
le = QtWidgets.QLineEdit()
lay = QtWidgets.QVBoxLayout(self)
for w in (self.edit, btn, le):
lay.addWidget(w)
self.edit.viewport().installEventFilter(self)
def eventFilter(self, obj, event):
if obj is self.edit.viewport() and event.type() == QtCore.QEvent.MouseButtonPress:
if event.button() == QtCore.Qt.LeftButton:
print('test')
return super(Widget, self).eventFilter(obj, event)
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
w = Widget()
w.show()
sys.exit(app.exec_())
My actual application is much more complicated than this, but the example below sums up the majority of my problem. I have multiple QLabels that I've subclassed to make them clickable. The labels display 16x16 images which requires a process of loading the images via Pillow, converting them to ImageQt objects, and then setting the pixmap of the label. In the example, I have 3 clickable QLabels that run the print_something function each time I click on them. My goal is to be able to hold the mouse down, and for each label I hover over, the function gets called. Any pointers would be great.
from PyQt5 import QtCore, QtWidgets, QtGui
from PIL import Image
from PIL.ImageQt import ImageQt
import sys
class ClickableLabel(QtWidgets.QLabel):
def __init__(self):
super().__init__()
clicked = QtCore.pyqtSignal()
def mousePressEvent(self, ev):
if app.mouseButtons() & QtCore.Qt.LeftButton:
self.clicked.emit()
class MainWindow(QtWidgets.QMainWindow):
def __init__(self):
super().__init__()
central_widget = QtWidgets.QWidget()
self.setFixedSize(300, 300)
image = Image.open("16x16image.png")
image_imageqt = ImageQt(image)
hbox = QtWidgets.QHBoxLayout()
hbox.setSpacing(0)
hbox.addStretch()
label01 = ClickableLabel()
label01.setPixmap(QtGui.QPixmap.fromImage(image_imageqt))
label01.clicked.connect(self.print_something)
hbox.addWidget(label01)
label02 = ClickableLabel()
label02.setPixmap(QtGui.QPixmap.fromImage(image_imageqt))
label02.clicked.connect(self.print_something)
hbox.addWidget(label02)
label03 = ClickableLabel()
label03.setPixmap(QtGui.QPixmap.fromImage(image_imageqt))
label03.clicked.connect(self.print_something)
hbox.addWidget(label03)
hbox.addStretch()
central_widget.setLayout(hbox)
self.setCentralWidget(central_widget)
def print_something(self):
print("Printing something..")
if __name__ == "__main__":
app = QtWidgets.QApplication(sys.argv)
main_window = MainWindow()
main_window.show()
sys.exit(app.exec_())
The cause of the problem is stated in the docs for QMouseEvent:
Qt automatically grabs the mouse when a mouse button is pressed inside
a widget; the widget will continue to receive mouse events until the
last mouse button is released.
It does not look like there is a simple way around this, so something hackish will be required. One idea is to initiate a fake drag and then use dragEnterEvent instead of enterEvent. Something like this should probably work:
class ClickableLabel(QtWidgets.QLabel):
clicked = QtCore.pyqtSignal()
def __init__(self):
super().__init__()
self.setAcceptDrops(True)
self.dragstart = None
def mousePressEvent(self, event):
if event.buttons() & QtCore.Qt.LeftButton:
self.dragstart = event.pos()
self.clicked.emit()
def mouseReleaseEvent(self, event):
self.dragstart = None
def mouseMoveEvent(self, event):
if (self.dragstart is not None and
event.buttons() & QtCore.Qt.LeftButton and
(event.pos() - self.dragstart).manhattanLength() >
QtWidgets.qApp.startDragDistance()):
self.dragstart = None
drag = QtGui.QDrag(self)
drag.setMimeData(QtCore.QMimeData())
drag.exec_(QtCore.Qt.LinkAction)
def dragEnterEvent(self, event):
event.acceptProposedAction()
if event.source() is not self:
self.clicked.emit()
I'm trying to catch a closeEvent for several dockWidgets that get added dynamically to a QMainWindow. It is unclear to me how I can figure out which widget has been closed.. Here's an simplified example:
class Example(QtGui.QMainWindow):
def __init__(self):
super(Example, self).__init__()
self.leftDockWidget = QtGui.QDockWidget('pick tool', self)
self.leftDockWidget.setWidget( QtGui.QLabel('a dock widget') )
self.addDockWidget( QtCore.Qt.LeftDockWidgetArea, self.leftDockWidget )
self.leftDockWidget.closeEvent = self.dockWidgetCloseEvent
self.show()
def dockWidgetCloseEvent(self, event):
print event
# how to get sender widget ?
event.sender() doesn't seem to exist..
any ideas ?
thanks
One way to achieve what you want would be to use an event filter:
from PyQt4 import QtGui, QtCore
class Example(QtGui.QMainWindow):
def __init__(self):
super(Example, self).__init__()
self.leftDockWidget = QtGui.QDockWidget('pick tool', self)
self.leftDockWidget.setWidget(QtGui.QLabel('a dock widget'))
self.addDockWidget(QtCore.Qt.LeftDockWidgetArea, self.leftDockWidget)
self.leftDockWidget.installEventFilter(self)
def eventFilter(self, source, event):
if (event.type() == QtCore.QEvent.Close and
isinstance(source, QtGui.QDockWidget)):
print source.windowTitle()
return super(Example, self).eventFilter(source, event)
if __name__ == '__main__':
import sys
app = QtGui.QApplication(sys.argv)
window = Example()
window.show()
sys.exit(app.exec_())
def dockWidgetCloseEvent(self, event):
self.sender()