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[JonB]

@john_hobbyist
What do you mean by "I use these method calls"? These methods are supposed to be overrides. Qt infrastructure calls them when it detects the mouse event, with the appropriate event parameter.

And anyway @SGaist was asking you put a debugging print() statement inside these override methods to make sure they are getting called.

[john_hobbyist]

I am trying some ready examples in order to understand the rationale. I run the first code from here: https://stackoverflow.com/questions/34220275/how-to-select-a-region-with-qrubberband-on-a-qlabel-like-in-ksnapshot

I have changed PyQt4 ---> PyQt5 and QtGui ----> QtWidgets. I also changed this line:

pixmap = QPixmap.grabWindow(app.desktop().winId())

with this:

pixmap = QScreen.grabWindow(app.desktop().winId())

but I get this error:

File "QRubberBandonaQLabelKSnapshot.py", line 47, in initUI
    pixmap = QScreen.grabWindow(app.desktop().winId())
TypeError: grabWindow(self, sip.voidptr, x: int = 0, y: int = 0, width: int = -1, height: int = -1): first argument of unbound method must have type 'QScreen'

Any idea what to do here?

[SGaist]

You're using it as if it were a static method which it's not. You need an instance of QScreen.

You can get one from your QApplication.

[john_hobbyist]

@SGaist Sorry I do not understand...how I get an instance from QApplication in QScreen?

[SGaist]

It's the other way around.

In any case, you should rather get the screen from your widget.

Take a look at the screenshot example.

[john_hobbyist]

@SGaist

I just try to see how to run the QRubberBand in PyQt5....

[SGaist]

Did you check the example from the class documentation ?

[john_hobbyist]

I added them to the main class. I am trying to call the methods, like this:

self.mousePressEvent(event)
self.mouseMoveEvent(event)

etc.

But what do I put inside/instead of "event"?

[mrjj]

@john_hobbyist

The code you showed higher up to drive the rubber band.
Or the docs @SGaist points to. they explain in detail what is needed.

def mousePressEvent(self, event):   ///// this set the start location of the band
    self.origin = event.pos()
    self.rubberband.setGeometry(
        QtCore.QRect(self.origin, QtCore.QSize()))
    self.rubberband.show()
    QtGui.QWidget.mousePressEvent(self, event)

def mouseMoveEvent(self, event): // this makes the band follow the mouse to adjust the size
    if self.rubberband.isVisible():
        self.rubberband.setGeometry(
            QtCore.QRect(self.origin, event.pos()).normalized())
    QtGui.QWidget.mouseMoveEvent(self, event)

def mouseReleaseEvent(self, event): // this is the end of the operation and you use the rectange defined by the band
    if self.rubberband.isVisible():
        self.rubberband.hide()
   rect = self.rubberband.geometry()

 ... then use rect for whatever you need

[john_hobbyist]

@mrjj: Thanks for your help! I am searching all morning. Here https://doc.qt.io/qtforpython/PySide6/QtWidgets/QRubberBand.html#more I don't see something about what to put inside the "event". The only I can understand is to use this inside events: https://doc.qt.io/qtforpython-5/PySide2/QtGui/QMouseEvent.html

[mrjj]

@john_hobbyist

Im not sure what you refer too ?

def mouseReleaseEvent(self, event): <<< this event ? the paramter ?

To use the rubberband, we use 3 functions as shown.

[john_hobbyist]

@mrjj
Yes, I try this:

self.mousePressEvent(event)

and the code requires to put something instead of "event". This is the error:

File "code.py", line 310, in __init__
  self.mousePressEvent(event)
NameError: name 'event' is not defined

[SGaist]

Where are you calling these methods from ?

[john_hobbyist]

@SGaist : Inside this method:

def __init__(self, parent=None):
   . . . 
   (code)
   . . . 
   self.mousePressEvent(event)
   self.mouseMoveEvent(event)
   self.mouseReleaseEvent(event)

. . . 

(other methods + code per method)

. . . 

def mousePressEvent(self, event):
   (code)

def mouseMoveEvent(self, event):
   (code)

def mouseReleaseEvent(self,event):
   (code)
   

which the first method of the class. Any idea?

[SGaist]

That's not how it works. These methods are automatically called when appropriate.

[john_hobbyist]

@SGaist : So I remove these lines?

self.mousePressEvent(event)
self.mouseMoveEvent(event)
self.mouseReleaseEvent(event)

What should I change?

[SGaist]

Implement the methods like shown in the QRubberBand class documentation.

[john_hobbyist]

@SGaist: Ok, I followed this: https://doc.qt.io/qtforpython/PySide6/QtWidgets/QRubberBand.html#qrubberband I put them into the Class. And that's it?

[SGaist]

That's the base yes.

[john_hobbyist]

@SGaist: It seems to get response, although I do not see the red rectangle... But the mouse events seem to recognize when I press or when I release the mouse. But I need to install rubberband because I get this error:

File "code.py", line 174, in mouseMoveEvent
  rubberBand.setGeometry(QRect(origin, event.pos()).normalized())
NameError: name 'rubberBand' is not defined

I am trying to fix it though! THANX!!!