Merge two pieces of code

[john_hobbyist]

@JonB: Hi, as I posted previously:

Traceback (most recent call last):
  File "code_2.py", line 333, in <module>
    screen_pixmap = QtGui.QPixmap.grabWidget(app.desktop()) 
NameError: name 'QtGui' is not defined
Segmentation fault (core dumped)

I have also tried this....

[SGaist]

You did not import the module.

[john_hobbyist]

@SGaist: Something else than these?

import os
import sys
import cv2
from matplotlib.figure import Figure
import numpy as np
from PyQt5.QtGui import QIcon
from PyQt5.QtWidgets import (QMainWindow, QApplication, QWidget,QAction, QFileDialog, QMenu, 
                             QToolBar, QHBoxLayout, QTreeView, QFileSystemModel, QSizePolicy, 
                             QMessageBox)
from PyQt5.QtCore import Qt, QDir, QStandardPaths, QFileInfo
import matplotlib.backends.backend_qt5agg as mpl_qt
from PyQt5 import QtWidgets, QtCore
from PyQt5.QtGui import QPixmap

[SGaist]

You import QPixmap directly so use it directly as well.

[john_hobbyist]

@SGaist: I used this:

screen_pixmap = QPixmap.grabWidget(app.desktop())

I get this:

Traceback (most recent call last):
  File "code_2.py", line 335, in <module>
    screen_pixmap = QPixmap.grabWidget(app.desktop()) 
AttributeError: type object 'QPixmap' has no attribute 'grabWidget'
Segmentation fault (core dumped)

I followed this: https://stackoverflow.com/questions/29260686/qpixmap-has-no-attribute-grabwindow

and I changed to this:

screen_pixmap = QScreen.grabWidget(app.desktop())

and I get this:

Traceback (most recent call last):
  File "code_2.py", line 336, in <module>
    screen_pixmap = QScreen.grabWidget(app.desktop()) 
AttributeError: type object 'QScreen' has no attribute 'grabWidget'
Segmentation fault (core dumped)

When I changed to this:

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

I get this:

Must construct a QApplication first.
Traceback (most recent call last):
  File "code_2.py", line 337, in <module>
    screen_pixmap = QScreen.grabWindow(app.desktop().winId()) 
AttributeError: 'NoneType' object has no attribute 'winId'
Segmentation fault (core dumped)

When I changed to this:

screen_pixmap = QScreen.grabWindow(app.desktop())

I get this:

Must construct a QApplication first.
Traceback (most recent call last):
  File "code_2.py", line 338, in <module>
    screen_pixmap = QScreen.grabWindow(app.desktop())#.winId()) 
TypeError: grabWindow(self, PyQt5.sip.voidptr, x: int = 0, y: int = 0, width: int = -1, height: int = -1): first argument of unbound method must have type 'QScreen'
Segmentation fault (core dumped)

I didn't find something about this...

[JonB]

@john_hobbyist
The last answer in the stackoverflow link you quoted claims to have "Full example for PyQt5". Did you at least try that? Not your own version of it, just exactly the example given there.

[john_hobbyist]

@JonB Yes, it works, but I try different rubberband code...please look at my first posts up...

[john_hobbyist]

This post is deleted!

[john_hobbyist]

What modifications should I do in the command?

[john_hobbyist]

I am trying to modify/incorporate from the correct running code from the stackoverflow that @JonB suggested. With this:

screen_pixmap = QScreen.grabWindow(app.primaryScreen(),QApplication.desktop().winId()).save(filename, 'png')

I get this:

Must construct a QApplication first.
Traceback (most recent call last):
  File "code_2.py", line 340, in <module>
    screen_pixmap = QScreen.grabWindow(app.primaryScreen(),QApplication.desktop().winId()).save(filename, 'png')
AttributeError: 'NoneType' object has no attribute 'winId'
Segmentation fault (core dumped)

And with this

screen_pixmap = QScreen.grabWindow(app.primaryScreen(),QApplication.desktop()).save(filename, 'png')

I get again this:

 construct a QApplication first.
Traceback (most recent call last):
  File "code_2.py", line 341, in <module>
    screen_pixmap = QScreen.grabWindow(app.primaryScreen(),QApplication.desktop()).save(filename, 'png')
TypeError: grabWindow(self, PyQt5.sip.voidptr, x: int = 0, y: int = 0, width: int = -1, height: int = -1): first argument of unbound method must have type 'QScreen'
Segmentation fault (core dumped)

in which I cannot find a reliable solution from google/stackoverflow...

[SGaist]

@john_hobbyist said in Merge two pieces of code:

grabWindow

This is not a class method, you need an instance of QScreen.

In what way is that related to your original QRubberBand question ?

[john_hobbyist]

@SGaist Yes, I try to use stackoverflow code that has an approach for what I am trying so many days to do. Please look previous posts. And these are errors...

[SGaist]

I already answered to the errors you are getting.

@SGaist said in Merge two pieces of code:

This is not a class method, you need an instance of QScreen.

You really should read the documentation of the classes you are using rather than just blindingly copy paste.

[john_hobbyist]

I have been making many changes all day. The rest of the application runs, but nowhere I can see a rubberband rectangle in order to select/printscreen an area. I get these warnings though...I am searching it, but any idea would help...

QWidget::paintEngine: Should no longer be called
QPainter::begin: Paint device returned engine == 0, type: 1
QPainter::end: Painter not active, aborted

[SGaist]

Where exactly are you doing custom painting ?

[john_hobbyist]

I don't know! This is the modified last part of my code:

if __name__ == "__main__":
    app = QApplication(sys.argv)
    icon = QIcon(os.path.join(selfDir, '_static', 'orthoview.ico'))

    app.setWindowIcon(icon)
    from PyQt5.QtWidgets import *
    data = take_screenshot()
    window = QWidget()
    layout = QtWidgets.QVBoxLayout(window) 

    pixmap = QPixmap()
    pixmap.loadFromData(data)
    label = QtWidgets.QLabel()
    label.setPixmap(pixmap)
    
    layout.addWidget(label)         
    geometry = app.desktop().availableGeometry()        
    window.setFixedSize(geometry.width(), geometry.height())        

    window = OrthoView()
    window.show()
    sys.exit(app.exec_())

I used/modified this:

import sys

from PySide2 import QtCore, QtGui, QtWidgets


def take_screenshot():
    from PyQt5 import QtCore as pyqt5c
    from PyQt5 import QtWidgets as pyqt5w

    screen = pyqt5w.QApplication.primaryScreen()
    winid = pyqt5w.QApplication.desktop().winId()
    pixmap = screen.grabWindow(winid)

    ba = pyqt5c.QByteArray()
    buff = pyqt5c.QBuffer(ba)
    pixmap.save(buff, "PNG")
    return ba.data()


if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)

    data = take_screenshot()

    pixmap = QtGui.QPixmap()
    pixmap.loadFromData(data)

    label = QtWidgets.QLabel()
    label.setPixmap(pixmap)
    label.show()

    sys.exit(app.exec_())

(source: https://stackoverflow.com/questions/59118938/type-error-when-calling-qscreen-grabwindow)

[JonB]

@john_hobbyist
Maybe I misunderstand, but you call take_screenshot()as the very first thing you do, before you have created or shown anything at all? What would you expect from that, logically?

EDIT
OK, you're trying to screenshot what's already on the screen? Sorry, I misunderstood. Still seems very early but may be correct. Ignore this post if it is :)

I'm not sure I see anything here to do with custom painting. Do you use a debugger? Do you step through your code to find out where your problems come from? We need you to (learn to) do that, people here don't know where the errors come in your code.

[john_hobbyist]

@JonB Yes, I am trying to find the errors!

[JonB]

@john_hobbyist
So, nicely, do you use some Python debugger to execute your code?

[john_hobbyist]

@JonB I write the code on a simple text editor and run it on Ubuntu's command line..