Qt 6.3 - Hackdot

Re:Qt 6.3 by dkersten on Tuesday April 12, 2022 @10:55AM (#31003569)

I built an editor for creating visualisations for an LED grid hardware project. The editor was built in QML (but with lots of C++). It had a grid visualising the LEDs as squares (I believe that was drawn, iirc, not using QML rectangles) And a timeline track editor where you could place effects (four tracks), drag them around, drag their length, select effects to edit their properties in a properties label etc.

Whole thing was built in about 3 days and I would say it was a huge success (visualisation crested with it was used at a gig of about 1.2k attendees and creating the editor meant being able to iterate quickly to create a visualisation the musicians were happy with, LEDs were attached to clothing). I certainly enjoyed the experience.

Doing it in Qt meant that I could write C++ code to “run” the visualisation, but with a different display implementation (editor version drew to the editor, hardware version outputted to the LED hardware, but the track runtime was the same code). QML made building the UI easy.

Nowadays I mainly do React-based web UI’s, but I still much prefer QML to html/react/css. I especially miss QML’d anchors for layouts.

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Re:Qt 6.3 by ravenstine on Tuesday April 12, 2022 @11:49AM (#31004282)

Thanks for providing an opposite opinion! I don't suppose there's video, photos, or code of your project? No worries if you don't. Just sounds really cool!

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Re:Qt 6.3 by HDevo on Tuesday April 12, 2022 @01:59PM (#31006160)

I'm not the parent, but I did something similar. It's an editor for fractal flames where the UI is done in QML and rendering and generation is done in C++ and OpenGL. https://github.com/chaoskit/chaoskit

I liked that QML allowed me to iterate quickly on the UI. It was really quick to just compose a bunch of components together and have something working. I also enjoyed the integration with the C++ side. Overall I found QML pretty solid. If I'd build a desktop app again, I'd definitely consider it.

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Re:Qt 6.3 by dkersten on Tuesday April 12, 2022 @03:07PM (#31006981)

I have the code on GitHub but I haven’t built the code in 4 years so don’t have a screenshot. Like I said, the code was written in about 3 days and QML allowed me to iterate quickly, but the resulting code quality isn’t great (since it was a once off project, built and used in the same week and then never used again, I didn’t clean it up or anything).

The editor simulated the LED strip using the same code to generate the effects as the on device version (which just ran without the UI and a different “driver” class implementation). It ran on a Raspberry Pi so the device wasn’t a microcontroller or anything, which made it easy to run the C++ code. In theory I could have made it run in a microcontroller but it wasn’t necessary for the project and time was limited.

Anyway, the code is here: https://github.com/danielytics/ledstudio

And the QML specifically is here: https://github.com/danielytics/ledstudio/blob/master/main.qm...

If I were to clean it up, I would at least split the different labels into their own QML files but hey, shortcuts were taken over those few days :)

Visually, it didn’t look all that great, but I’m not a UI person either and it was rushed. Functionally it could have been improved too, but it did what it was supposed to and it worked well. It allowed us to create various LED effect sequences quickly and play them back later.

I personally quite like QML. It’s not perfect, by any means, but I like using it more than React (which is what I’ve been using on projects since due to needing to be web based).

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