I also think Qt/QML is a very underrated technology. I have been developing a handwritten notes for Linux/Windows using Qt Quick for quite some time [0]. The experience has been a mixed bag though.
I've encountered tons of bugs (many of them still unfixed) that I had to find very ugly workarounds for.
Also, while a declarative style UI language can have a lot of benefits, it does also have a lot of limitations. For example, in my application I required a (infinite) canvas to rendering the ink strokes, which would be a perfect job for QGraphicsView, but there is no equivalent in Qt Quick. So I had to roll out my own component (which uses Skia under the hood), but that was quite painful. Since Qt 6, the Qt Quick scenegraph is rendered with a custom RHI backend (abstracting over Vulkan, Metal, OpenGL and DirectX) which I had a lot of trouble integrating with third party engines (I really wish they had a WebGPU backend).
Great write-up! It would be useful if various PKMs would settle on a similar format for recording (nested) tasks, dates and metadata, as it seems to have become the standard way to store kanban boards and similar 'enhanced' views. Currently there exist various strategies ranging from embedding JSON as comments to esoteric (non-markdown) formats, often trailing at the end of each task. This makes the source look cluttered and difficult to edit/navigate.
IMO, metadata (such as date ranges) could instead be stored as empty links leading each task (or by showing a custom placeholder symbol such as '@'), paving the way for a 'linked' data format while resulting in a same-width list for easy lookups and editing:
For instance, the above tasks would link to the virtual '30..31.md' and '29..30.md' files which collect all backlinked tasks for the provided daterange (akin to Obisidan/Logseq/etc).
In an ideal world, the task marker could hold a custom symbol and linked metadata itself, but would result in non-standard (GFM) markdown:
I've worked with Qt about 15 years writing several applications both for work and for fun and overall I think it's a really powerful platform. Not without it's idiosyncrasies and quirks of course.
That being said I find that QML is complete trash. It's fine for simple UIs with minimal logic and prototypes but for anything beyond that you'll always need to implement the logic in C++ and this is where the pain enters the picture. A lot of effort will be spent maintaining the glue code that lets the two worlds comminicate. The tooling is poor and QMLs poor typing makes it hard to ever change anything from types to available methods..
Generally speaking QML has terrible shortcomings in its lack of good typing, debugging abilities, error reporting or general maintainability of the code. It's your typical "write once" platform where the cost comes later if/when you need to maintain and evolve the software later on.
I think the fact that Qt went with Javascript as the scripting language for QML wasn't a smart decision - especially resulting in poor type safety. That said, they have improved the situation by a lot with required properties, Q_ENUM where you can now share enums between C++ and QML etc etc.
I don't agree that QML is just for simple UIs, that's exactly what I tried to demystify - my block editor is a very complex project spanning around 20,000+ lines of code - and still managed to be the most performant block editor in all my tests.
Contrary to you, I love the separation between the logic being written in C++ and UI in QML I think it's absolutely a great combo - QML is such a great language to write UIs in and C++ is a performant compiled language that (I, personally) love writing logic in. Also, communicating between C++ and QML components is straightforward with Q_PROPERTYs and signal and slots.
Yes sure I've heard that Qt6 improves the integration and type safety but I haven't tried that yet myself.
Communicatingn with signals and slots and using Qt Property system is straightforward yes but even more straightforward is to when you don't have to use it. The real problem is when you change your properties or your underlying types or the methods, their names or signatures and NOTHING tells you which part of your QML code will be affected. You just have to.. kinda know. In practice you'll of course miss something and then it'll just blow up at runtime with some "bla bla is undefined" error.
That being said if you're comfortable to use it and find it works for you more power to you. I'll just stick to my widgets. :)
I think the QML linter detects that but may require maintaining some extra files that tell which methods and properties are available. Not sure if they can be generated if using C++ and more native tools since I've been using QML with Rust.
This is brilliant work and I love the Qt ecosystem.
Can’t help but imagine the things we could’ve had if Apple wasn’t pushing the horror of Swift down everyone’s throat by blocking alternatives in so many tiny ways.
If you mean due to lack of C++ for doing GUIs, Google and Microsoft have also long left C++ to the dust, in what concerns GUI frameworks.
Even Microsoft, for all its C++ use, has never produced anything better than MFC to this day, and only Windows team cares about XAML C++, others rather use React Native or Webview2 alongside C++.
It is up to third parties to use frameworks like Qt.
I mean specific APIs and targets are required to be written in Swift (e.g. widgets) + iOS/macOS dev tooling is hostile to any attempt at bringing in your own preferred language stack. I wouldn't be surprised if Apple's "glasses" or other tiny devices make it even harder to stray from the "one true path".
Calling ObjC via your language of choice is like the easiest thing possible, solved multiple times over. Signing and notarizing outside of Xcode is also a solved problem.
IME people bitch about this but when push comes to shove just don’t want to do the required work, typically on flimsy grounds. It’s just not that hard.
The increase in Swift-only frameworks will eventually be a problem but it’s typically not a blocker right now.
Swift and SwiftUI on macOS are the most complete UI framework that is native, fast, performant and works very well.
Basically no other platform comes even close in terms of ease of use and performance. The best would be to extend that kind of framework on Windows (and/or Linux) and make it work same / similar.
I've always lamented that QML and QtWidgets are separate rather than integrated. It would be awesome if there was a declarative way to specify much of the same information that you have to specify programmatically with QtWidgets (e.g., the cumbersome process of defining nested sizers), and then you could write code to handle the actual "business logic". But instead we have two totally separate UI frameworks where you can either use the nice native QtWidgets or you can have a nice declarative UI definiton, but not both.
Looks great, and it has some features and polish that I would love Logseq to have natively, but overall I prefer the customisation potential of logseq with tags, templates, block refs etc.
> and Microsoft tends to abandon each new UI framework every five years
So use the old one? Your first link literally mentions two ancient frameworks that are not abandoned (win32 and MFC)
But you're right
> So, it's more useful to ask: what do we expect from good native apps?
The challenge, though, is there isn't really a good comprehensive list of those things the would allow you to compare the framework you use to native. And you can't patch everything if you don't even know where the holes are
So that why this is correct...
> Qt apps typically don't look or behave exactly like native apps,
... but this is theoretical
> I'm going to argue that they can.
Yes, of course they can, but to do in reality requires too much effort, so you end up with with the state mentioned in the first part of the quote. (that's the whole point of the framework - to handle that complexity for you, and if the whole huge QT can't do that even though "they can" why do you think a single dev can?)
> At the same time, I've grown fond of Markdown. The idea that all my notes are formatted in a syntax that will essentially last as long as computers exist—plain text—is very reassuring
That's a very common mistake as well. It's true only for very primitive parts of markdown, which is rather limiting for notes, but if you venture into the more complicated extensions/HTML area, then it's not different from any other format - as long as the format codecs work, it's usable. Like, even word doc is plain ugly XML text, so will exist forever?
> rendering the underlying Markdown when the cursor is inside a Markdown-formatted text—was quite challenging.
Indeed, because it's not fit for purpose.
> For example, if the cursor is inside this bold and italicized text it will show as *bold and italicized text*.
So you now have constant layout shifts when you simply move your caret around.
I've worked with QtWidgets and I have mixed feelings about the extensive (1) documentation about integrating C++ with QML and QtQuick.
Here's a quick history lesson (as I understand it):
- QtWidgets the original C++ QT graphics library.
- Around 2008 or something, they introduced QML and QtQuick. This was basically declarative UI + javascript for logic.
- QtWidgets is considered 'done' and all new features and dev is basically happening in QML / QtQuick.
- ...as described in this post, the current recommended 'best practice' is to avoid writing a pile of javascript spaghetti and bridge between C++ for logic and QML for UI.
So, long story short: We've moved from a robust C++ framework, to a javascript backed framework to 'appeal to the masses', but it's kind of hard to build a whole application that way, and so 'best practice' is to go back and write your logic in C++.
Does that seem weird to anyone else?
> While powerful, Qt Widgets lack some essential modern features, in my opinion, such as declarative UI, bindings, behaviors, anchors, and more. These features enable the creation of beautiful, animated UIs simply and quickly, as seen in QML.
Hum. QML is certainly declarative.
I'd love to see a breakdown of specifically what features you can't do with widgets, and why having a js <-> c++ bridge is better than not having one.
Don't get me wrong; if you want to write a 100% javascript QML application, that's cool. Go for it... but when you're writing a C++ application and choosing, deliberately, to implement you UI in another language and communicate with that UI via a bridge...
...well, let's just say, if you had another option (eg. just use C++), wouldn't that make sense?
Couldn't you do the the same thing with react native components and logic in C++? (You could) Why is this any better than just writing a react native UI? Or a flutter UI?
You could do any kind of UI, even fully native, if you're implementing the application is c++ and then just doing cross language <-> to the ui.
Generally, QtWidgets is better suited for making traditional desktop UIs with dialog boxes, common controls, etc... It is not really in the spirit of QtWidgets to do things like custom behavior, animation, etc... You do whatever the host OS gives you, in fact, you don't even care, that's Qt's job.
QML is better suited for apps that want full control of their UIs, styling, etc... Which is a more modern way (doesn't mean better!).
It is clear that the author wants the latter, so QML it is.
And yes, it makes sense to use a different language for the UI in this case, with C++ bindings, C++ is not that great for designing UIs. In fact, with QtWidgets, you typically don't use C++ to design your UI. Instead, you use Qt Designer, a graphical tool that works on .ui files (xml), that are then compiled into C++ classes that your derive from, which is a form of binding between two languages: C++ and .ui/xml. You can use C++ directly, sometimes you have to, like when the UI is dynamically generated, but for something like a dialog box, using the graphical tool is much more convenient.
As someone who doesn't do too much GUI programming on Linux, I find QML quite useful, actually.
Small effects and simple state switches ("disable/hide this group of inputs when the user disables the 'advanced' checkbox") can be written in simple code. The advanced plumbing (custom control rendering, window management) is left to native code.
There's a delicate balance there that I can imagine will be difficult to maintain long-term, but many applications just need a handful of buttons and maybe a text field somewhere to do their job, and that's where QML shines.
> Couldn't you do the the same thing with react native components and logic in C++? (You could) Why is this any better than just writing a react native UI? Or a flutter UI?
The tooling, that is why.
Having QtCreator, Qt Design Studio, compiling QML to native code, debugging experience.
React Native has all the gotchas from JavaScript and poor tooling for developers that never left the CLI world.
Flutter depends on Dart, a programming language that was rescued from oblivion thanks to Flutter, and is pretty much useless everywhere else.
I've encountered tons of bugs (many of them still unfixed) that I had to find very ugly workarounds for. Also, while a declarative style UI language can have a lot of benefits, it does also have a lot of limitations. For example, in my application I required a (infinite) canvas to rendering the ink strokes, which would be a perfect job for QGraphicsView, but there is no equivalent in Qt Quick. So I had to roll out my own component (which uses Skia under the hood), but that was quite painful. Since Qt 6, the Qt Quick scenegraph is rendered with a custom RHI backend (abstracting over Vulkan, Metal, OpenGL and DirectX) which I had a lot of trouble integrating with third party engines (I really wish they had a WebGPU backend).
[0] https://scrivanolabs.github.io
IMO, metadata (such as date ranges) could instead be stored as empty links leading each task (or by showing a custom placeholder symbol such as '@'), paving the way for a 'linked' data format while resulting in a same-width list for easy lookups and editing:
For instance, the above tasks would link to the virtual '30..31.md' and '29..30.md' files which collect all backlinked tasks for the provided daterange (akin to Obisidan/Logseq/etc).In an ideal world, the task marker could hold a custom symbol and linked metadata itself, but would result in non-standard (GFM) markdown:
It would be up to the editor to render this metadata accordingly.That being said I find that QML is complete trash. It's fine for simple UIs with minimal logic and prototypes but for anything beyond that you'll always need to implement the logic in C++ and this is where the pain enters the picture. A lot of effort will be spent maintaining the glue code that lets the two worlds comminicate. The tooling is poor and QMLs poor typing makes it hard to ever change anything from types to available methods..
Generally speaking QML has terrible shortcomings in its lack of good typing, debugging abilities, error reporting or general maintainability of the code. It's your typical "write once" platform where the cost comes later if/when you need to maintain and evolve the software later on.
I think the fact that Qt went with Javascript as the scripting language for QML wasn't a smart decision - especially resulting in poor type safety. That said, they have improved the situation by a lot with required properties, Q_ENUM where you can now share enums between C++ and QML etc etc.
I don't agree that QML is just for simple UIs, that's exactly what I tried to demystify - my block editor is a very complex project spanning around 20,000+ lines of code - and still managed to be the most performant block editor in all my tests.
Contrary to you, I love the separation between the logic being written in C++ and UI in QML I think it's absolutely a great combo - QML is such a great language to write UIs in and C++ is a performant compiled language that (I, personally) love writing logic in. Also, communicating between C++ and QML components is straightforward with Q_PROPERTYs and signal and slots.
Yes sure I've heard that Qt6 improves the integration and type safety but I haven't tried that yet myself.
Communicatingn with signals and slots and using Qt Property system is straightforward yes but even more straightforward is to when you don't have to use it. The real problem is when you change your properties or your underlying types or the methods, their names or signatures and NOTHING tells you which part of your QML code will be affected. You just have to.. kinda know. In practice you'll of course miss something and then it'll just blow up at runtime with some "bla bla is undefined" error.
That being said if you're comfortable to use it and find it works for you more power to you. I'll just stick to my widgets. :)
Oh, yes!
Even Microsoft, for all its C++ use, has never produced anything better than MFC to this day, and only Windows team cares about XAML C++, others rather use React Native or Webview2 alongside C++.
It is up to third parties to use frameworks like Qt.
Calling ObjC via your language of choice is like the easiest thing possible, solved multiple times over. Signing and notarizing outside of Xcode is also a solved problem.
IME people bitch about this but when push comes to shove just don’t want to do the required work, typically on flimsy grounds. It’s just not that hard.
The increase in Swift-only frameworks will eventually be a problem but it’s typically not a blocker right now.
Those that think it shouldn't be, end up yak shaving trying to bring UNIX and C concepts to platforms that no longer care about that.
Basically no other platform comes even close in terms of ease of use and performance. The best would be to extend that kind of framework on Windows (and/or Linux) and make it work same / similar.
> For instance, Apple's SwiftUI is reportedly slow[1][2][3][4],
Wow just noticed my blog post is on the front page! Will try to respond to all comments here soon.
So use the old one? Your first link literally mentions two ancient frameworks that are not abandoned (win32 and MFC)
But you're right
> So, it's more useful to ask: what do we expect from good native apps?
The challenge, though, is there isn't really a good comprehensive list of those things the would allow you to compare the framework you use to native. And you can't patch everything if you don't even know where the holes are
So that why this is correct...
> Qt apps typically don't look or behave exactly like native apps,
... but this is theoretical
> I'm going to argue that they can.
Yes, of course they can, but to do in reality requires too much effort, so you end up with with the state mentioned in the first part of the quote. (that's the whole point of the framework - to handle that complexity for you, and if the whole huge QT can't do that even though "they can" why do you think a single dev can?)
> At the same time, I've grown fond of Markdown. The idea that all my notes are formatted in a syntax that will essentially last as long as computers exist—plain text—is very reassuring
That's a very common mistake as well. It's true only for very primitive parts of markdown, which is rather limiting for notes, but if you venture into the more complicated extensions/HTML area, then it's not different from any other format - as long as the format codecs work, it's usable. Like, even word doc is plain ugly XML text, so will exist forever?
> rendering the underlying Markdown when the cursor is inside a Markdown-formatted text—was quite challenging.
Indeed, because it's not fit for purpose.
> For example, if the cursor is inside this bold and italicized text it will show as *bold and italicized text*.
So you now have constant layout shifts when you simply move your caret around.
Here's a quick history lesson (as I understand it):
- QtWidgets the original C++ QT graphics library.
- Around 2008 or something, they introduced QML and QtQuick. This was basically declarative UI + javascript for logic.
- QtWidgets is considered 'done' and all new features and dev is basically happening in QML / QtQuick.
- ...as described in this post, the current recommended 'best practice' is to avoid writing a pile of javascript spaghetti and bridge between C++ for logic and QML for UI.
So, long story short: We've moved from a robust C++ framework, to a javascript backed framework to 'appeal to the masses', but it's kind of hard to build a whole application that way, and so 'best practice' is to go back and write your logic in C++.
Does that seem weird to anyone else?
> While powerful, Qt Widgets lack some essential modern features, in my opinion, such as declarative UI, bindings, behaviors, anchors, and more. These features enable the creation of beautiful, animated UIs simply and quickly, as seen in QML.
Hum. QML is certainly declarative.
I'd love to see a breakdown of specifically what features you can't do with widgets, and why having a js <-> c++ bridge is better than not having one.
Don't get me wrong; if you want to write a 100% javascript QML application, that's cool. Go for it... but when you're writing a C++ application and choosing, deliberately, to implement you UI in another language and communicate with that UI via a bridge...
...well, let's just say, if you had another option (eg. just use C++), wouldn't that make sense?
Couldn't you do the the same thing with react native components and logic in C++? (You could) Why is this any better than just writing a react native UI? Or a flutter UI?
You could do any kind of UI, even fully native, if you're implementing the application is c++ and then just doing cross language <-> to the ui.
Right?
[1] - https://doc.qt.io/qt-6/qtqml-cppintegration-overview.html
QML is better suited for apps that want full control of their UIs, styling, etc... Which is a more modern way (doesn't mean better!).
It is clear that the author wants the latter, so QML it is.
And yes, it makes sense to use a different language for the UI in this case, with C++ bindings, C++ is not that great for designing UIs. In fact, with QtWidgets, you typically don't use C++ to design your UI. Instead, you use Qt Designer, a graphical tool that works on .ui files (xml), that are then compiled into C++ classes that your derive from, which is a form of binding between two languages: C++ and .ui/xml. You can use C++ directly, sometimes you have to, like when the UI is dynamically generated, but for something like a dialog box, using the graphical tool is much more convenient.
Small effects and simple state switches ("disable/hide this group of inputs when the user disables the 'advanced' checkbox") can be written in simple code. The advanced plumbing (custom control rendering, window management) is left to native code.
There's a delicate balance there that I can imagine will be difficult to maintain long-term, but many applications just need a handful of buttons and maybe a text field somewhere to do their job, and that's where QML shines.
The tooling, that is why.
Having QtCreator, Qt Design Studio, compiling QML to native code, debugging experience.
React Native has all the gotchas from JavaScript and poor tooling for developers that never left the CLI world.
Flutter depends on Dart, a programming language that was rescued from oblivion thanks to Flutter, and is pretty much useless everywhere else.