[AussieWog93]

>I think modern OS stacks are in a similar boat, at least Windows and macOS.

I come from a background as a EEE mainly writing embedded code before somehow stumbling into frontend code (in win32, Cocoa and Qt) at my old job.

From my experience, OS-Level APIs definitely have more in common with Electron or Qt than they do "bare metal". To make the top left pixel red on a bare metal system or RTOS, you simply write `framebuffer[0] = 0x00ff0000`.

For win32 or Cocoa, you need to create a window, alter its flags to ensure it's borderless, change its size and posistion to 1x1 and [0,0] (or [0, screen_height] on the Mac), strip away the drop shadow, respond to regular paint events and pray like hell that nothing else draws over the top of it.

>True low level control is kind of a pain

It depends on what you're trying to achieve. If you're trying to get something highly responsive that looks exactly like the UI spec, most libraries tend to make this job harder when the abstractions leak and you're forced to rely on bizarre hacks that make no sense and feel genuinely demoralising to implement.

Dear ImGui, which exposes far more of the low-level internals than any other API, is an absolute joy to build GUIs in and significantly easier than something which "holds your hand" at every step.

[simonh]

Making the top left pixel red just isn't something you should be doing in a GUI environment anyway, it doesn't make any sense. For something like that you should probably be dropping to a full-screen mode like most graphics heavy games anyway, in which case it's pretty easy on modern OSes.

The desktop GUI is just one subsystem in a modern OS, and you don't have to use it if you don't want to. If you do use it then there are tradeoffs, of course, but that's always true of anything you use.

[Al-Khwarizmi]

> Making the top left pixel red just isn't something you should be doing in a GUI environment anyway, it doesn't make any sense.

Never cheated in Minesweeper, I presume?

[edoceo]

One of the versions had the high scores saved in ini file (3.1? 95?). My dad was amazed I solved large one in 15s. Then he found it. Then I learned about the read-only attribute.

[nyanpasu64]

Dear ImGui does not support Arabic (right-to-left, glyph shaping) and will not support Arabic (https://github.com/ocornut/imgui/issues/1343). I don't think it supports accessibility either.

As much as I struggle with Qt's APIs (aging janky Widgets, half-baked QML on the desktop, the item models are an impenetrable byzantine enterprisey API that's simultaneously too open-ended, not flexible enough since it imposes its add/remove/move schema on your model, and too buggy), building a GUI from the ground up is not going to give you internationalization or accessibility, and Qt is.

[AussieWog93]

>Dear ImGui does not support Arabic (right-to-left, glyph shaping) and will not support Arabic (https://github.com/ocornut/imgui/issues/1343).

Vanilla ImGui doesn't, but I both wrapped my head around and then rewrote the text renderer in all of 2 days as a junior dev.

This version could support arbitrarily many UTF-8 codepoints with kerning and all and had a negligible performance hit on the machines I tested on. I never upstreamed it (left the company before the product that was using it shipped, actually), but it wouldn't be too hard to reproduce.

That's what I love about exposed, lower-level frameworks like Dear ImGui.

We didn't aim for accessibility, but I'm sure that would have also been semi-trivial for a dedicated dev who understands what's required.

[lavabiopsy]

Maybe you want to help this person who is trying to integrate harfbuzz: https://github.com/ocornut/imgui/issues/4227

The other major thing missing in relation to that is input method support.

The problem with those type of APIs and accessibility is that implementing screen reader support basically means making it retained mode in some capacity, because accessibility APIs expect you to export a tree of objects and push state updates.

[AussieWog93]

>Maybe you want to help this person who is trying to integrate harfbuzz: https://github.com/ocornut/imgui/issues/4227

Looks like theirs is far more advanced than mine (mine would just generate a texture per string and cache it, the main problem it solved was being able to display non-ASCII filenames). I don't think there's much I could contribute to them at all.

>accessibility APIs expect you to export a tree of objects and push state updates

Is this an inherent limitation with the tech itself, or just an arbitrary API limitation?

[lavabiopsy]

This is the way these platform APIs are designed, you could theoretically make a screen reader that doesn't need that and just asks the app to recompute its state every time, but they don't currently work that way.

[lavabiopsy]

IMO, Dear ImGui is great for its original purpose (debugging GUIs, simple demos), but once you start adding complexity, custom layouts and custom widgets on top of it the state tracking gets to be just as bad as retained mode if not worse. Unless there was some best practice that I missed, one has to take great pains to avoid re-running the layout multiple times per frame, whereas a retained mode GUI would be able to handle that easily.

[AussieWog93]

Maybe it's just a personal experience thing? I came across both ways of thinking as a junior dev, so to me retained mode was just a footgun rich environment.

I could imagine if you had decades of experience using retained-mode, though, then you'd find that way of thinking more natural.

[lavabiopsy]

This affects all GUIs, if you have a lot of elements then you have to be careful not to propagate complex updates through the whole tree because it kills your performance. There are various tools to deal with this, one of them is making it retained mode, but I would say basically all of those tools come with more footguns in that the GUI can easily end up in an inconsistent state. That's what you trade for performance.

[AussieWog93]

I've heard that argument before, yet for almost all apps I've used in real life the opposite is true.

Game UIs are (from what I understand) written almost exclusively ImGui-style, with every single widget being fed updated state data every single frame as part of the game loop.

Yet, for whatever reason, even crazy-complex UIs like SupCom's seem to have no issue rendering in realtime with an entire 3D game running in the background, while simply resizing the window I'm typing into right now (a single textedit on a static HTML page) creates visible lag and chews up full CPU on a 2015 Macbook.

That's not to say retained-mode GUIs can't be performant (embedded systems rely on retained-mode to have reasonable performance), but on a modern system it seems like the loss in performance caused by inefficiently synchronising state in retained-mode GUIs is several orders of magnitude higher than the losses caused by pushing a couple of hundred textures every frame in an ImGui context.

[lavabiopsy]

The thing is those are likely to be simple GUIs. Those are a great use case for immediate mode. But try it with something that has a lot of:

- Wrapping text labels

- Widgets that are similar to CSS flexbox where the size of elements depends on other elements

- List/tree widgets or text editor widgets with large datasets in them

And then you will notice performance tanks. Think of trying to build a text editor that way, if you opened a 5MB text file, you would have to rescan the whole 5MB and compute reflow for it every time.

[PaulDavisThe1st]

Game UIs do not generally involve user interaction based on the position of a pointer within the 2D screen geometry. They generally have a very limited event/input system that only takes effect via an overlay. Objects do not come and go from the "model" as a matter of course. They certainly do a LOT of drawing, and they do it very fast, but the challenges of UI design (particularly toolkit design) don't really reside in "how do we draw this stuff really fast".

I do often reflect on how fast game UIs draw, and compare that to the headaches we have in the UI of a digital audio workstation. It generally seems almost inconceivable how we could be so slow in comparison. But then I think about all the ways the user has to interact with the actual UI (not the backend data model), and it starts to seem like a different sort of programming model entirely.

[maxxk]

I play games very infrequently, but my anecdata is the opposite: games usually have laggy UI with an inconsistent reaction to input events, noticeable latency, frequent breakage and generally worse user experience (and of course mostly without the ability to resize anything, to compare with browser), even when compared to browsers and Electron apps.

[kaba0]

And would you want your laptop taking as much power writing a word document as it takes to run a AAA game?

[dkersten]

I love the immediate mode style of developing, but ImGUI specifically, at least without third party patches and extensions, has very awkward and limited layout (for example, I'm still waiting for this to get merged[1], which would make it easier), its styling support is relatively minimal (but it can be made look pretty nice) and its accessibility support is non-existent. I also find the API slightly clunky, although its not bad once you get used to it.

Overall, I really like Dear ImGUI and I love how easy it is to expose data to a UI through it. Its much more pleasant to use than a traditional retained mode widgets API. But Dear ImGUI isn't a good general purpose UI (nor was it designed to be one), although I could see the immediate mode API work well for one. I started making a complex editor for a toy engine in it and while it worked ok, the reasons above made me cut it back to just some basic in-engine stuff and the rest is exposed over an optional embedded web server module and a react app as the editor. Its only a toy, but you would use the in-engine ImGUI editor to see the scene rendered in-engine, move objects around etc, but you would use the react app to edit object properties, add assets and behaviours and whatnot. It made it much easier to create rich editors for things like behavior trees, node graphs, etc. Although since its just a toy, I didn't implement a lot of this stuff yet and haven't had time lately to get back to it.

[1] https://github.com/ocornut/imgui/pull/846

[Certhas]

Isn't this obvious? I mean if you need that kind of control of the screen then you shouldn't be working inside a WM by definition, and the Toolkits are built for building interfaces in the context of WMs. Right? I definitely don't want your random application to be able to draw on arbitrary parts of the screen and then prevent anyone else from drawing over it. Your use-case might sound simple at first glance, but it's truly odd if you think about how I interact with applications, and how I expect to be able to manage them.

[AussieWog93]

Of course. I'm not saying that using Win32 or Cocoa are wrong (at least for a Desktop OS where you don't want to hand over full control to an app), just that they're closer on the spectrum to Qt than bare metal.

[cmrdporcupine]

Arguably win32 GUI or Cocoa are not "OS level" APIs; yes some aspects of them are invoked through syscall type interfaces (esp win32) but not consistently and the operating system itself is entirely usable without them. Especially Cocoa. You can boot a Mac into a BSD shell without ever running Finder and the GUI.

Writing into a framebuffer is arguably as much of an abstraction these days as many of these toolkits. In the modern world of GPUs and display controllers a framebuffer itself is already N levels away from the "physical" display hardware. We're not in VGA land anymore. Some aspects of the OS or the OS's interaction with the display driver may present something like a linear framebuffer to you, but underneath that is a world of GPU textures and buffers and display controller abstractions.

When I think of OS-level APIs I think of ioctl, mmap, file descriptors and sockets. I guess that's my Linux bias showing?

[overgard]

Well, that's kind of what I'm driving at with things like the win32 api being a bit too high level and still kind of sucking. An example would be the GDI (the way you draw simple graphics). Like, it's in the worst of both worlds in that it's both slow and annoying to use. Or you can use DirectX and draw things fast, but you need to know a lot more. I think my point is mainly that OS's might be better off just giving you things like DirectX (and mmap and ioctl, etc.) and leaving off things like the GDI.

I know right now Microsoft keeps making like 50000 new UI frameworks and part of me is like, just knock it the fuck off, give me some style guidelines and some super-efficient very low level no-frills API's and let me just build apps off a library like Qt that abstracts it.

[pjmlp]

Unless you plan to write an OS personality yourself, there is no way to use Windows without Win32.

[nine_k]

But most of the time you don't want to make individual pixels red. You want to blit bitmaps and fill rectangles, preferably without pegging the CPU. Here the simple memory-mapped framebuffer is less helpful, especially if you have specialized hardware to do such work.

Of course this does not apply if all you have is a screen connected via SPI to an MCU's GPIO pins. But you won't expect much graphical sophistication from such a device anyway.

[raxxorrax]

Just start to implement the ~300-400 functions listed here and the underlying systems supporting them. How long could that take, a whole weekend?

https://github.com/torvalds/linux/blob/master/arch/x86/entry...

[dkersten]

> To make the top left pixel red on a bare metal system or RTOS, you simply write `framebuffer[0] = 0x00ff0000`.

Really? In my brief experience it was more like sending a bunch of commands over SPI/I2C/UART to some LCD module. Which isn't thaaaat different from how an OS driver communicates with a GPU, only the commands are far, far more complex, so using an OS-level API avoids having to do it by hand.