Do you think it is worth attempting to try and get QOpenGLWidget to work with PlotCurveItem or do you think that's a lost cause until there is some upstream fix?

Looking at the Qt Bucktracker, I have found

• QTBUG-86962
• QTBUG-82181
• QTBUG-73040 (this one is interesting, talks about background style-sheets, can apparently avoid when running w/o stylesheets)

I didn't notice any workarounds in those issues unfortunately.

On PyQt6, after removing the enableExperimental check in PlotCurveItem.paint, examples/MouseSelection.py works for me (with adding pg.setConfigOptions(useOpenGL=True) at the top of the file).

How was PlotCurveItem broken for you?

EDIT: wait, I messed something up, investigating further...

EDIT2: Got it working with a ridiculous if-check in PlotCurveItem.paint

        if HAVE_OPENGL and \
            (
                (
                    getConfigOption('enableExperimental') and \
                    hasattr(QtOpenGL, 'QGLWidget') and \
                    isinstance(widget, QtOpenGL.QGLWidget)
                ) or \
                (
                    hasattr(QtWidgets, 'QOpenGLWidget') and \
                    isinstance(widget, QtWidgets.QOpenGLWidget)
                )
            ):
            self.paintGL(p, opt, widget)
            return

with PyQt6 on macOS, this block of code is run (enableExperimental has to be set to False).

Given this is the only place that enableExperimental is used, should we just get rid of that option (and if we get rid of that option, should we ditch every reference of QGLWidget instead of QOpenGLWidget?)

EDIT3:

I also had to add this to my PyQt6 block:

    try:
        from PyQt6 import QtOpenGL
    except ImportError as err:
        QtOpenGL = FailedImport(err)

I'm about to try with PySide6

EDIT4: Got it working with PySide6 with the same changes as I made for PyQt6.

I get the following on Windows 10 when using QOpenGLWidget on either Qt5 and Qt6. So maybe it is OS dependent.

I didn't import QtOpenGL in Qt.py for Qt6 because it is not used. So, in the previous code, Qt6 users would get a QtOpenGL import failure and thus have HAVE_OPENGL = False.

I have modified the code to allow Qt6 users to turn on enableExperimental. After all, it is an opt-in.

I just tried it on Linux and it seems to work.

Given this is the only place that enableExperimental is used, should we just get rid of that option (and if we get rid of that option, should we ditch every reference of QGLWidget instead of QOpenGLWidget?)

As a user, I could want to enable useOpenGL without enabling enableExperimental. I would like to ditch QGLWidget even if that breaks Windows. Users affected are those who had opted in to enableExperimental.

I get the same problem on windows with PyQt5 5.15 and PyQt6.

This PR LGTM, code is much cleaner, no more ambiguity between QGLWidget vs. QOpenGLWidget... Thanks so much for doing this @pijyoi !

Maybe the following code might give a clue to someone knowledgeable with Windows OpenGL.
The data gets drawn if the x and y coords lie between [-1, 1]. It's not drawn within the axes either.

import numpy as np
import pyqtgraph as pg
pg.setConfigOption('useOpenGL', True)
pg.setConfigOption('enableExperimental', True)

app = pg.mkQApp()
win = pg.plot()

xxx = np.linspace(-1, 1, 1000)
yyy = np.sin(2*np.pi*3*xxx)
curve = pg.PlotCurveItem(x=xxx, y=yyy, pen='g', clickable=True)
win.addItem(curve)
              
app.exec_()

@pijyoi do you happen to have a hidpi display or use fractional scaling (150% or 175%?) by chance?