@mrjj Thank you very much! Problem solved.

@nekitamtip what I would do is not rely on the call stack as @Kent-Dorfman points out its unreliable at best and not available due to threading issues (now that does not mean it cannot be just means it would take a lot of work and time to figure it out if it is even possible). So with that said and a much easier methodology for handling this in code regardless of the coding language you use here is what I do.

Any place you plan to "raise" an error or handle an exception include enough information so that you can easily determine where that error occurred along with what that error was. In your example I would change the raise to read:

raise Exception('MyTreadWorker.job_with_exception_raised :' + error_message)

This basically (at a glance) tells you where the error occurred in detail and if the error was dynamic what that error was -- note if the error is static then simply replace [ ' + error_message ] with [ Description of Error ' ] again do this any place you raise an error and/or use a try except -- further I would actually call an error_handler routine in case I want to switch from live debugging to production debugging and want those errors posted to an error-log of some sort.

Basically it is considered quality programming that when you raise an error or handle an exception that you report enough information back so that with that error message you (1) Know exactly where the error occurred (2) Know exactly what the error was (3) and include any extra information that might be available that would make fixing that error much easier

If you do this as a standard within all your code you will soon find out that tracking done bugs becomes a trivial task.

It appears they are using the following version of the overloaded QImage call

QtGui.QImage(uchar *data, int width, int height, int bytesPerLine, QImage::Format format, QImageCleanupFunction cleanupFunction = nullptr, void *cleanupInfo = nullptr)

Thus the h*np.nbytes[np.uint8] would be the bytesPerLine

That being said here is an augmented bit of documentation (https://doc.qt.io/qt-5/qimage.html#QImage-5) covering this function that I think will answer the basic question, cannot guarantee it will not raise additional questions though

This constructs an image with the given width, height and format, that uses an existing memory buffer, data. The width and height must be specified in pixels. The bytesPerLine specifies the number of bytes per line (stride). For information on Stride see: (https://medium.com/@oleg.shipitko/what-does-stride-mean-in-image-processing-bba158a72bcd)

The buffer must remain valid throughout the life of the QImage and all copies that have not been modified or otherwise detached from the original buffer. The image does not delete the buffer at destruction. You can provide a function pointer cleanupFunction along with an extra pointer cleanupInfo that will be called when the last copy is destroyed.

If format is an indexed color format, the image color table is initially empty and must be sufficiently expanded with setColorCount() or setColorTable() before the image is used.

So I solved my problem.
It turns out QImage needs the image to be a flat numpy array.
Here is how it's done:

qrgb_dict = {'r': lambda x: QtGui.qRgb(x, 0, 0), 'g': lambda x: QtGui.qRgb(0, x, 0), 'b': lambda x: QtGui.qRgb(0, 0, x)} colortable = [qrgb_dict[color](i) for i in range(256)] img = QtGui.QImage(arr, w, h, w, QtGui.QImage.Format_Indexed8) img.setColorTable(colortable)

Where arr is an array of shape (h,w) and with uint8 values in 0-255

I was able to solve this by switching to pycharm, for some reason spyder did not want to cooperate, kept getting DLL not found errors, "application failed could not find or load qt plugin could not be initialized", and importing QCharts would not work. everything seems to be working now thorough pycharm.

OK, so the issue turned out to be something different. We are using QtPy and it needs the environment variable QT_API set to pyside2 for our Windows setup. For some reason the environment passed to QProcess isn't inheriting that variable and it was defaulting to pyside. Setting it manually to pyside2 by calling setProcessEnvironment on our QProcess before the start call gets everything working.

Not sure if this is a PySide2 bug or not. The QProcess.execute documentation says:
"The environment and working directory are inherited from the calling process."
but it doesn't say this explicitly for start.

@krzysieklfc said in Gamma correction for display:

Shouldn't Qt somehow handle the color correction when I'm 'telling it' to view the image?

no! why should it?

I don't quite understand why you are dividing by 256?
Also whats the returning type of GetR()/GetG()/GetB()?

@blossomsg
Hi
That is fine, please marked as solved then :)

By writing a small demo to complete my post, I found the issue. As it might be helpful to somebody else, here it is:

demo.scxml:

<?xml version="1.0" encoding="UTF-8"?> <scxml xmlns="http://www.w3.org/2005/07/scxml" version="1.0" binding="early" xmlns:qt="http://www.qt.io/2015/02/scxml-ext" name="plop.scxml" qt:editorversion="4.7.1"> <state id="State_1"> <qt:editorinfo scenegeometry="144.50;162.05;84.50;112.05;120;100" geometry="144.50;162.05;-60;-50;120;100"/> </state> </scxml>

demo.py:

#!/usr/bin/env python import sys from PySide2.QtCore import QObject, QCoreApplication, SLOT, Slot from PySide2.QtScxml import QScxmlStateMachine class Backend_1(QObject): def __init__(self, machine): super(Backend_1, self).__init__() self.machine = machine self.machine.connectToState("State_1", self, SLOT("s1_active(bool)")) @Slot(bool) def s1_active(self, active): if active: print('Backend_1::State_1: enter') self.submachine = QScxmlStateMachine.fromFile('demo.scxml') b = Backend_2(self.submachine) self.submachine.start() else: print('Backend_1::State_1: exit') class Backend_2(QObject): def __init__(self, machine): super(Backend_2, self).__init__() self.machine = machine self.machine.connectToState("State_1", self, SLOT("s1_active(bool)")) @Slot(bool) def s1_active(self, active): if active: print('Backend_2::State_1: enter') else: print('Backend_2::State_1: exit') if __name__ == '__main__': app = QCoreApplication(sys.argv) machine = QScxmlStateMachine.fromFile('demo.scxml') b = Backend_1(machine) machine.start() sys.exit(app.exec_())

If you run this, you expect to see:
Backend_1::State_1: enter
Backend_2::State_1: enter

But, the second statemachine does not seem to start. To fix it, you need to store the instance of Backend_2 (eg: self.b = Backend_2(self.submachine)). I guess it was garbage collected, so all the states/events connections were broken.

Meanwhile, if you think my design patter is bad, I'm willing to learn :)

Hi,

Looks like there's some problem with the PySide 2 implementation. You should check the bug report system to see if it's something known. If not, please consider opening a new report providing your example and as much details as possible about your current setup.

Figured out my issue. I just needed to instantiate a QQmlDebuggingEnabler object. Calling QtQml.QQmlDebuggingEnabler() before instantiating my QApplication was enough.

I figured it out finally, some things around OOP are still very confusing for me, I guess I need time and more experience to settle all down. Below is a functional example of simple window with two QToolButtons - a regular one and modified one.

@JonB: I think that there is no difference between using PyQt and PySide, except for import statements, and loading ui, I think that PyQt cannot load ui file directly, it must be converted to py, maybe I'm wrong.

Now there are four things that bother me:

how to use regular QtToolButton as a classic button with drop-down menu (see my example), it seems that triggered signal is always called. Is it designed to work that way? If I don't add signal in code than button does nothing? are there any major flaws in my example that should be corrected/fixed? how to "inject" my custom made object into ui at wanted location? In my example I just inserted it inside grid_layout. Can I make a placeholder somehow? Let's say I have a more complicated window with many widgets, for example:

and I want to replace that Add Something button with custom one. What would be the best procedure to do this?

is calling GUI directly from a ui XML file smart thing to do or it would be better to convert it to py first?

My example, program.py, and form.ui:

#!/usr/bin/env python3 # -*- coding: utf-8 -*- """ Docs """ import os, sys from PySide2 import QtWidgets, QtUiTools class CustomToolButton(QtWidgets.QToolButton): ''' CustomToolButton description ''' def __init__(self, parent=None): ''' Constructor ''' super(CustomToolButton, self).__init__(parent) self.setPopupMode(self.MenuButtonPopup) self.triggered.connect(self.setDefaultAction) return None class Program(QtWidgets.QWidget): ''' Program description ''' def __init__(self, parent=None): ''' Constructor ''' super(Program, self).__init__(parent) self.program_path = os.path.dirname(os.path.realpath(__file__)) self.loader = QtUiTools.QUiLoader() ui_file_path = os.path.join(self.program_path, 'form.ui') self.window = self.loader.load(ui_file_path, parent) self.setup_ui(self.window) return None def setup_ui(self, window): self.grid_layout = window.gridLayout # tool button created in Qt Designer self.tool_btn = window.toolButton ### THIS RUNS EVERY TIME BUTTON IS CLICKED NO MATTER ### WHAT ACTION YOU CHOOSE FROM DROP-DOWN MENU ### IT SEEMS THAT IN THIS CASE YOU CANNOT USE BUTTON LIKE ### CLASSIC BUTTON, ### THEREFORE IT SEEMS THAT "setDefaultAction" MAKES NO SENSE self.tool_btn.triggered.connect(self.clicked_tool_btn) # custom tool button self.custom_tool_btn = CustomToolButton() self.custom_tool_btn.setText('Custom button') self.custom_tool_btn.setMinimumSize(150,50) self.custom_tool_btn.setMaximumSize(150,50) self.grid_layout.addWidget(self.custom_tool_btn) self.define_ui_elements() def define_ui_elements(self): # tool button created in Qt Designer tool_btn_menu = QtWidgets.QMenu(self) tool_btn_menu.addAction('Action 1', self.action1_activated) tool_btn_menu.addAction('Action 2', self.action2_activated) tool_btn_menu.addAction('Action 3', self.action3_activated) tool_btn_default_action = QtWidgets.QAction('Action 1',self) self.tool_btn.setMenu(tool_btn_menu) self.tool_btn.setDefaultAction(tool_btn_default_action) # custom tool button ''' 1) creating actions ''' action1 = QtWidgets.QAction('Action 1', self) action2 = QtWidgets.QAction('Action 2', self) action3 = QtWidgets.QAction('Action 3', self) ''' 2) creating connections ''' action1.triggered.connect(self.action1_activated) action2.triggered.connect(self.action2_activated) action3.triggered.connect(self.action3_activated) ''' 3) creating btn menu ''' custom_tool_btn_menu = QtWidgets.QMenu(self) custom_tool_btn_menu.addAction(action1) custom_tool_btn_menu.addAction(action2) custom_tool_btn_menu.addAction(action3) ''' 4) setting up menu and default action ''' self.custom_tool_btn.setMenu(custom_tool_btn_menu) self.custom_tool_btn.setDefaultAction(action1) ### THIS RUNS EVERY TIME BUTTON IS CLICKED NO MATTER WHAT ACTION YOU CHOOSE FROM DROP-DOWN MENU def clicked_tool_btn(self): # calling action1_activated() because it is default option self.action1_activated() print('Qt Designer button is clicked.') def action1_activated(self): print('Action 1 activated.') def action2_activated(self): print('Action 2 activated.') def action3_activated(self): print('Action 3 activated.') if __name__ == '__main__': program = QtWidgets.QApplication(sys.argv) main_window = Program() main_window.window.show() sys.exit(program.exec_()) <?xml version="1.0" encoding="UTF-8"?> <ui version="4.0"> <class>Form</class> <widget class="QWidget" name="Form"> <property name="geometry"> <rect> <x>0</x> <y>0</y> <width>400</width> <height>300</height> </rect> </property> <property name="sizePolicy"> <sizepolicy hsizetype="Fixed" vsizetype="Fixed"> <horstretch>0</horstretch> <verstretch>0</verstretch> </sizepolicy> </property> <property name="minimumSize"> <size> <width>400</width> <height>300</height> </size> </property> <property name="maximumSize"> <size> <width>400</width> <height>300</height> </size> </property> <property name="windowTitle"> <string>Form</string> </property> <layout class="QGridLayout" name="gridLayout"> <item row="1" column="0"> <widget class="QToolButton" name="toolButton"> <property name="minimumSize"> <size> <width>150</width> <height>50</height> </size> </property> <property name="maximumSize"> <size> <width>150</width> <height>50</height> </size> </property> <property name="text"> <string>QtDsgnrBtn</string> </property> <property name="popupMode"> <enum>QToolButton::MenuButtonPopup</enum> </property> </widget> </item> </layout> </widget> <resources/> <connections/> </ui>