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Comment by tenaciousDaniel | Hacker News Reader

As someone who is completely ignorant about QT, what are the arguments for using it? I looked at their product page and it seems incredibly expensive. Why pay to develop for a particular platform?

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It's LGPL, you don't need to pay. Also...

> Why pay to develop for a particular platform?

Because Qt is not a particular platform but one of few cross-platform GUI framework.

I would definitely call Qt a platform, just like Java is a platform (it actually has a lot of similarities to Java). The platform happens to run on multiple other, lower-level platforms.

I would definitely call Qt a toolkit, because, you know, honesty. Java is a language you know.

It simplifies developing cross-platform native apps. Imagine electron apps, except it uses less resources, and has a consistent look and feel with the rest of the OS. You also don't have to pay if you don't want, but Qt is licensed under the LGPL so you have to be aware of what you can and can't do under that license.

Spoiler alert: you can do anything with LGPL as long as you don't modify Qt.

And IIRC no static linking unless you make your source available.

Is that just actual static linking, or is bundling everything in a directory okay?

Bundling a directory is fine if you're still dynamically linking.

Correct. As long a linking is dynamic, Qt doesn't care how/where the Qt libs are distributed. They typically recommend bundling for Windows and using system packages for Linux.

No, you only have to make your proprietary compiled object files available. what lgpl requires is for the user to be able to update the LGPL parts - so Qt in this case and this does not need your code.

Source: https://www.gnu.org/licenses/gpl-faq.en.html#LGPLStaticVsDyn...

Every Qt application I've ever used has been ... off.

Granted, it's closer than Swing. That's a pretty low bar. We need to either start qualifying this ("it's a good GUI toolkit for a cross-platform one"), or accepting that this is a scale (10 is "actually native", 0 is "just looks like Motif everywhere"). I'd give Qt 8/10 -- it's pretty good, and the screenshots look great but after a moment using it I'll say "wait, I think I know why everything feels just a little bit off".

As a counter to that, you've only got one set of data points, the ones you noticed. Potentially there are dozens or hundreds of well-made Qt apps that you haven't noticed, and so they by definition wouldn't be a part of your dataset.

> Every Qt application I've ever used has been ... off.

even Microsoft OneDrive ? even battle.net ? even your AMD drivers ? even Telegram ?

Those programs definitely do not use the same UI conventions as the rest of the platform.

Yeah but if you use Qml you can do whatever you want. That's the magic.

If you want to develop to responsive cross-platform application, it's the best choice. It's basically industry standard in embedded platforms at this point.

It's not expensive is you have a business that makes any money. It's free if you don't modify qt source itself and follow LGPL.

> Why pay to develop for a particular platform?

Qt runs on Windows, Linux, macOS, iOS, Android, WinRT, VxWorks, QNX and others. [0]

You don't get one platform, you get just about all of them.

[0] https://doc.qt.io/qt-5/supported-platforms.html

I tried porting some Qt code to iOS and Android a couple of years ago — I found the experience to be extremely lacking.

I’m not a fan of Qt or C++, but I will admit it is at least a very pragmatic and efficient choice for Linux GUIs. It’s much less than that on mobile.

and now the web too!

It's expensive because it doesn't really have any competition. Your car's infotainment center was probably written using Qt.

Electron is eating a bit of their lunch but it lacks a few features yet, uses a lot of resources comparatively, and doesn't support the same targets or developer communities that Qt does.

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