QT6 and matplotlib

GaryN

I am now adding a matplotlib graph to my system.

From my understanding, I need to drag and drop on a QWidget; which will contain my plot.

I have then followed a series of instructions on producing matplotlib graphs; all of which have worked fine.

However, these all use the idea of building the form items (a QWidget) and then setting this as the central widget (self.setCentralWidget(sc))

Obviously, I have dropped a QWidget onto my form and want the plot to appear within that object.

Using the working examples I have, I get to the following point:

sc = MplCanvas(self, width=5, height=4, dpi=100)
sc.axes.plot([0, 1, 2, 3, 4], [10, 1, 20, 3, 40])
widget = self.window.findChild(QWidget, 'plotWidget')

The form runs without issue or warnings but, obviously, the QWidget (named plotWidget on the form) does not appear and nothing appears inside: I haven't assigned sc to it yet.

How do I do this assignment?
Or am I on the wrong track?

JonB

@GaryN
I have never used Matplotlib. If I understand you right. You want to put an MplCanvas()-runtime-generated object, which is a QWidget, onto a form you have designed.

So you can do any of:

Just addWidget(sc) somewhere in the desired place. You don't need a QWidget placeholder on the form at design-time.
Replace the design-time added QWidget with your sc (you may have to removeWidget(yourWidget)).
Retain your design-time added QWidget. At runtime add e.g. a QHBoxLayout onto that widget, and then addWidget(sc) onto that layout.

GaryN

@JonB

I really appreciate your help on all of this. :)

From your three suggestions, I get the sense that building the form as I have been is possibly the wrong way?

Anyway, just sticking to this situation at present. I did have the addWidget(sc) aspect, but how do I define it's (x, y) position on the existing form?

I have a QTabWidget with (currently) 2 tabs. How do I direct the addWidget to ensure it goes within the right tab?

GaryN

@JonB

Ah, I just re-read your third bulletpoint and initially got it wrong!

Yes, that might work; since all the examples I have make the sc widget be the central widget; and that QWidget would then sit exactly where I wanted it, with the matplotlib object residing inside exactly as my example copies have it in the single window!

Am I coorect in my interpretation there?

JonB

@GaryN
Well it puts it wherever you tell it to put it. If you put it in the centre of something that's where it will appear. Give it a try and see.