How to scroll a QChart as realtime data come in

[d_stranz]

To be honest I can't remember having much related discussions with you. But as you have written similar statements several times it would be fair to elaborate what exactly you have problems with ?

It was a long time ago, back in the Qwt listserver days when you were first implementing Qwt 6.0, and it involved how arguments were being passed. In certain cases, the argument was a const pointer, but the instance on the receiving end took over control of the pointer's lifetime. The const-ness was what bothered me. You argued that this was simply telling the caller that the receiver would not change the state of the object's content, but my feeling was that if the receiver was eventually going to destroy the object you couldn't get more non-const than that. In the rest of Qt when an instance takes control of another's lifetime, such as the QObject hierarchy, the pointer is passed as non-const. It was a religious argument, mostly, and sort of silly as I look back on it but at the time it really bothered me. I am sorry for bringing it up.

I had many more problems with the big architectural changes that took place between Qwt5 and Qwt6, which would have involved rewriting major parts of my code to accommodate them. If I were starting fresh with new code, I would probably use Qwt6 now. In a way, since I am considering QCustomPlot and others you could say I am starting fresh, so I'll look at Qwt6 too. But none of what I can see does what I really want, which is a single library that will produce 2D and 3D plots of all sorts.

[Uwe]

It was a religious argument, mostly, and sort of silly as I look back on it ...

Try to step in my shoes for a moment:

someone starts a discussion about some detail - in your case about removing a const keyword - that has zero effect on application or library code. As the maintainer I have to respond - even if I don't even have much of an opinion about it. Finally the user does not like my answer, is frustrated and starts posting negative recommendations for the complete library.

I had many more problems with the big architectural changes that took place between Qwt5 and Qwt6, which would have involved rewriting major parts of my code to accommodate them.

But this is a totally different story, one about stable APIs.

Look at Qt: it has been heavily criticized because of all the changes that happened between Qt3/4. As a consequence it has very strict compatibility policies since those days.
But is this much better: we now have 2 different graphic stacks without any migration path. The old one has fallen into maintenance mode and the new one suffers from design problems, that can't be fixed before Qt6. We even saw Quick Controls 2 being started instead of solving the problems of Quick Controls 1.

I don't expect all users being happy when APIs are changing, but for Qwt there have only been only 2-3 substantial API changes in ~20 years. And having one with Qwt6 was unavoidable - I couldn't support Qt3 forever.

But none of what I can see does what I really want, which is a single library that will produce 2D and 3D plots of all sorts.

There once was Michas QwtPlot3D ( http://qwtplot3d.sourceforge.net/ ) library. When he lost his interest nobody had been found, who had enough interest and/or skills to keep it alive.
The code is still there - if you are unhappy with what others are doing: make things better.

Uwe

[d_stranz]

Try to step in my shoes for a moment

Like I said, I'm sorry for bringing it up and I apologize for doing so. Qwt5 was great and I was enthusiastic about using it. Moving to Qwt6 would have required me to make big code changes as well as swallow coding conventions that disturbed me at the time, so I chose not to do it. I should have kept my opinions to myself and let others form their own.

So I am sorry and will not mention it again. You have done a great service to the Qt community by adopting Qwt, continuing to improve upon it, and by participating actively in supporting those who want to use it on this forum and elsewhere. You've released it under license terms that allow its use anywhere, and haven't asked for fees for commercial use. It is admirable of you for doing it and your company for allowing you.

But this is a totally different story, one about stable APIs.

It goes beyond stable APIs. Somewhere between Qt 5.4 and later versions, disabled menu items stopped responding to hover events. I was relying on these events to enable / disable menu items based on my application state. When I switched to 5.5 or 5.6 (don't remember) users started to complain that they could no longer do things because the menus were always disabled. So I got stuck on 5.4.1 for a while until I decided to just enable everything and deal with it in other parts of the code.

Probably the Qt organization has had just too many ownership and management changes over the past few years and they have lost some focus in the process. Software is coming out under the Qt banner that isn't well thought-out.

QwtPlot3D

Yes, and it produces nice plots, but it is based on such an old version of OpenGL that it would require nearly a complete rewrite to bring it up to current standards. I don't know if I have tried building it with Qt5, so it might need more than just an OpenGL update.

Anyway, we've hijacked this thread, so maybe we can bury it and move on?

[mustermann.klaus@gmx.de]

Well, harmony is not a save haven. But it is the ocean.
Thanks to both of you for greatly contributing to my knowledge.

[Uwe]

...and your company for allowing you.

Not really important, but for the record: there has never been any company involved. All work being done for Qwt is/was done in free time.

Uwe

[d_stranz]

there has never been any company involved. All work being done for Qwt is/was done in free time.

Some companies in the US, particularly near here in the Silicon Valley, consider anything you do in your free time as their property if it uses the same skills you use on the job. Luckily for you and us that doesn't seem to be the case with Qwt.

Qwt3d - I don't know if I have tried building it with Qt5, so it might need more than just an OpenGL update.

After some effort, it does build and the examples run with Qt5 (64-bit Qt 5.9.0 MSVC on Windows to be precise). The last update was over 10 years ago. If I can find the free time, I might adopt it and bring it into the modern age.

[Uwe]

After some effort, it does build and the examples run with Qt5 (64-bit Qt 5.9.0 MSVC on Windows to be precise). If I can find the free time, ...

That would be cool - let me know if you need some support from the Qwt related part.

By the way: Guðjón finished his work on the Qwt python wrapper ( https://github.com/GauiStori/PyQt-Qwt ) and with an updated version of QwtPlot3d he might be interested to do the same for QwtPlot3D. Then we would have everything back, that existed for Qt4/Qwt5.

Uwe