Matching 2 .tiff images pixel-by-pixel

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!!!

jsulm

@john_hobbyist said in Matching 2 .tiff images pixel-by-pixel:

NameError: name 'rubberBand' is not defined

So, did you define rubberBand?