The Windows Boot Spinner Is a Font, Not an Animation

Description

This meme is a screenshot of a tweet from the user Xeno (@XenoPanther) that reveals a piece of technical trivia. The tweet reads, "Did you know that the spinner seen in modern Windows boot screens is stored as a font?" Below this text is a screenshot of the Windows Character Map utility. The application window shows the font "Segoe Boot Semilight" is selected. The character grid displays a series of glyphs that are actually the individual frames of the familiar dotted circle loading animation from the Windows boot screen. The bottom of the window indicates these are in a private use area of the font. The humor comes from the surprising and clever engineering hack of implementing a loading animation not as a video, GIF, or drawn graphic, but as a sequence of characters in a font. For senior developers, this is an amusing insight into the creative, low-level solutions required for processes like OS booting, where full graphics capabilities may not yet be available. It highlights how engineers use unconventional methods to solve problems under strict constraints

Common Tags

Windows OperatingSystems UXDesign UnicodeSupport CharacterEncoding Bootloader UXIrony

Comments

123

Anonymous ★ Top Pick Implementing a loading spinner as a font is peak 'we need this to work before the graphics driver loads' energy

Anonymous ★ Top Pick

Implementing a loading spinner as a font is peak 'we need this to work before the graphics driver loads' energy
Anonymous

Of course the Windows boot spinner lives in Segoe Boot - when the graphics stack isn’t up yet, you do what any seasoned dev would: hijack the Private-Use Unicode range and let DrawText() handle your 60 FPS animation
Anonymous

This is peak 'it's not a bug, it's a feature' energy - Microsoft engineers storing boot animations in a font file because when you're rendering graphics before the graphics subsystem loads, you work with what you've got. Next they'll tell us BSOD error codes are actually just really aggressive emoji
Anonymous

Ah yes, the classic Microsoft engineering approach: 'We need a boot spinner.' 'Just make it a font.' 'But shouldn't we use SVG or - ' 'FONT. IT. NOW.' Turns out when you're Microsoft, every problem looks like a TrueType nail. Though I'll admit, storing animation frames as glyphs in a Private Use Area is actually brilliant - zero dependencies, hardware-accelerated rendering via the font engine, and it ships with the OS. It's the kind of elegant hack that makes you simultaneously respect and question the Windows team's architectural decisions. Next you'll tell me the BSOD is just a really aggressive CSS theme
Anonymous

Peak OS engineering: the Windows boot spinner is a font - use the one rendering path guaranteed pre-driver, animate Private Use Area glyphs, and ship “progress” as typography
Anonymous

Boot spinners as fonts: Because bootloader devs knew trig for arcs wastes cycles when font engines are preloaded and GPU-ready
Anonymous

Of course the Windows boot spinner is a font - vector glyphs render before the graphics stack is up, so the first thing your machine boots is a kerning demo
D Y 2y

Spritemap
1. @SamsonovAnton 2y
  
  Too easy and much less resource-consuming. 🤓
  
  D Y 2y
  
  Don't sure need to measure. Font is vector, usually. Spritemap is rastr. So it can take more place.
  
  @SamsonovAnton 2y
  
  1 bpp bitmap of fixed resolution vs multiple vectors with floating-point parameters? I doubt it. However, I was referring to CPU consumption when rendering curves vs painting bitmaps.
  
  @ZgGPuo8dZef58K6hxxGVj3Z2 2y
  
  Bitmaps don’t scale
  
  @SamsonovAnton 2y
  
  Who cares? Are Windows icons scalable, or still pre-rendered raster images?
  
  @ZgGPuo8dZef58K6hxxGVj3Z2 2y
  
  It depends which ones. But the later ones are fonts too. Check MDL2 assets or fluent icons on google
  
  @SamsonovAnton 2y
  
  I mean the icons what are used for application shortcuts and document type identification in Explorer. Aren't they still essentially the same ICO they used to be since 1990-s? And boot-screen animation is many times less critical for UI scalability than desktop images.
  
  @ZgGPuo8dZef58K6hxxGVj3Z2 2y
  
  Yes those are but thats legacy component. Nowdays packages should have icons not plain exe files
  
  @ZgGPuo8dZef58K6hxxGVj3Z2 2y
  
  And the boot screen is kinda important it does have a lot of places where it van show you progress of something. Like rollback or disk check or install status or automatic repair
  
  @MadDelBastard 2y
  
  1bpp bitmap looks worse than ttf, because bitmap not uses AA, also Windows usually shows other text on same screen like "Welcome" and uses ttf anyway. So there is no point to use bitmaps in this case I think.
  
  @CcxCZ 2y
  
  In context of text legibility hard disagree there. Especially on lower resolution the difference is massive IME. (I had many angry rants on this topic in the context of early Android devices with 320x240 screens and such - and no way to select or even install bitmap font which would make the text at such resolution actually legible) However this is just pretty animation effect and I believe they do have scalable text on the screen already, so *shrug*. The font shaper will most likely prerender the glyphs to set resolution anyway.
  
  @MadDelBastard 2y
  
  in this case charset for loading icon will be prerendered too, because both outputs just textout ¯\_(ツ)_/¯
  
  @CcxCZ 2y
  
  Yup. it doesn't really matter here. Also I'm the kind of person that really wants to see the kernel/init/rc logs by default.
  
  @ZgGPuo8dZef58K6hxxGVj3Z2 2y
  
  Fonts are efficient af
2. @ZgGPuo8dZef58K6hxxGVj3Z2 2y
  
  Nope its vector
@ZgGPuo8dZef58K6hxxGVj3Z2 2y

At least on windows
@ZgGPuo8dZef58K6hxxGVj3Z2 2y

Ms has a lot of patents on improving it
@ZgGPuo8dZef58K6hxxGVj3Z2 2y

And rendering resolution independently
@ZgGPuo8dZef58K6hxxGVj3Z2 2y

Since windows 8 scaling is pretty much a key point
@ZgGPuo8dZef58K6hxxGVj3Z2 2y

And fonts have a lot of enginering to make them look good on weird scaling factors or fontsizes
@ZgGPuo8dZef58K6hxxGVj3Z2 2y

As they contain optional metadata for grid snapping
@ZgGPuo8dZef58K6hxxGVj3Z2 2y

This is a hint where to round the floats in case it doesn’t align with the pixel grid of your screen. Then fonts dont look like they used different strength for different lines in the charavter
@ZgGPuo8dZef58K6hxxGVj3Z2 2y

1 char has at most just a few triangles and even old af PCs can do that
@CcxCZ 2y

Window decorations in Win9X were also done by special font.
1. @ZgGPuo8dZef58K6hxxGVj3Z2 2y
  
  Yup very efficient
@endisn16h 2y

they render fonts in the kernel btw 💀💀💀💀
1. @Agent1378 2y
  
  You place the skulls like it is a bad thing
  
  @purplesyringa 2y
  
  because it is?
  
  @Agent1378 2y
  
  It's not. It's for performance. Windows graphical performance was a lways a priority and it still is much better then for example X. Linux has been suffering from userspace graphics for decades.
  
  @purplesyringa 2y
  
  hmm, maybe. i guess i'm just thinking as a server gal. lack of exploit vectors matters more than bits of performance for me
  
  @CcxCZ 2y
  
  Ring 0 doesn't make code run magically faster.
  
  @Agent1378 2y
  
  Yes, thats what X was telling us for years and now they plan to move to the kernel at least partially, LOL. It's not the ring 0 it's the thing you do there, bare metal instead of another syscall
  
  @CcxCZ 2y
  
  WTF are you talking about? Ring 0 is about as bare metal as you get (via documented means anyway). X11 always was primarily thin client network protocol in it's design. This has nothing to do with kernel mode and all with copying data around and interacting back and forth between processes. But there has been optional direct rendering in there (opengl/mesagl) literally since 90s.
  
  @Agent1378 2y
  
  So why then X was always considered sluggish? Are they always using all these network protocols for the local machine rendering?
  
  @purplesyringa 2y
  
  Yes
  
  @CcxCZ 2y
  
  Generally yes.
  
  @Agent1378 2y
  
  Well I can only ROFL to that😁😁😁😁😁
  
  @purplesyringa 2y
  
  I mean, no one even thought X would be used for local graphics back then
  
  @Agent1378 2y
  
  20 years passed, X or derivatives are still used. Write new clean solution, people!
  
  @CcxCZ 2y
  
  Personally I'm fan of https://arcan-fe.com/about/ It supports both X11 and Wayland interfaces as well as it's own shared memory interface (unified for video, audio and input). And it has reasonable security model for a change.
  
  @purplesyringa 2y
  
  Guess what it's called?
  
  @Agent1378 2y
  
  What?
  
  @purplesyringa 2y
  
  Wayland
  
  @Agent1378 2y
  
  So, is every Linux using it? Does it make windows as agile and responsive as windows on Windows are?😁
  
  @purplesyringa 2y
  
  It's been a long time since I've used Windows as a main OS, but subjectively I'd say it's quite performant
  
  @purplesyringa 2y
  
  Not every Linux distribution uses it, but it's getting increasingly popular, is a default almost everywhere, and mainstream software typically supports Wayland
  
  @Agent1378 2y
  
  Hahaha LOL. I switched to Mint after Ubuntu went unity🤮 and look here https://forums.linuxmint.com/viewtopic.php?t=389541
  
  @Agent1378 2y
  
  Since 2011 I only have Linux as vmware guest on windows host so I don't know either
  
  @CcxCZ 2y
  
  No but now you can have non-rectangular windows. Progress! (TBF I found any recent Windows install to be pretty bad UI latency wise. Which is less about drawing primitives and more of every application being a resource hog by default.)
  
  @Agent1378 2y
  
  LV426 visited?😁
  
  @CcxCZ 2y
  
  Not a fan myself. It's very Freedesktop who at start claimed to work on "simple compatible subset across desktop interfaces", but ended up being complexity for the sake of complexity and pushers of Gnome nonsense. In this case mostly doing bad design from start and instead of rearchitecturing they just pile workarounds and additions.
  
  @CcxCZ 2y
  
  That was actually one of the major improvements the libre XFree86 project did early on https://en.m.wikipedia.org/wiki/MIT-SHM
  
  @purplesyringa 2y
  
  TIL, thanks
  
  @CcxCZ 2y
  
  For most applications it matters very little. Or matteted at the time. The rendering was CPU-bound and the resolution was small. Today most things are bound by RAM speed and resolutions are huge. Also ever since COMPOSE extension (somewhere in 2010s IIRC) it was fairly feasible to do direct rendering mostly everywhere. However from what I've talked with EFL folks (among the first ones to support various rendering backends in their GUI) the drivers for accelerated rendering were mostly so bad that it made things actually slower.
  
  @Agent1378 2y
  
  Even proprietary from video card makers are bad?
  
  @CcxCZ 2y
  
  Oh yes, especially those. Hardware vendors don't make good software developers. :-] And it wasn't until ATI got bought by AMD that we've even seen any useful specs for those cards so libre drivers could be written. Everything before was pure reverse engineering.
  
  @CcxCZ 2y
  
  Like, NVidia is single-handedly responsible for the "taint" flag in kernel. I.e. if you load those drivers kernel devs would refuse to look at any issue with that system, as it was notorious for random memory corruptions in unrelated parts of kernel. Really bad code there.
  
  @Agent1378 2y
  
  I remember I used nvidia propiertary drivers with Ubuntu 4/5/6 and the software was quote ok. Recompiled kernel module easily with one command after upgrading kerrnel and booting up in console. And somewhere around Ubuntu 6 or 7 it started to recompile itself automatically when needed on the fly. Compared to nv driver this looked very solid. We even played bzflag often and it ran fine
  
  @CcxCZ 2y
  
  For long time the driver choice boiled down to: Libre drivers: stable & slow NVidia: go fast and break things ATI/AMD: be happy if it works at all I remember circa 2004/2005 (my first Gentoo system!) applications compiled against NVidia OpenGL drivers just crashed when you switched to implementation provided by Mesa. Or vice-versa, can't remember which. Those were the wild times. Ironically I've heard that major contribution to Linux on desktop was the introduction of Xbox. Because suddenly people were okay with having a games-only computer and didn't need fast 3D acceleration on their work machine. That's how the drivers were. (And since I haven't cared about AAA games for a loooong time I don't really how and if that changed)
  
  @ZgGPuo8dZef58K6hxxGVj3Z2 2y
  
  Tbf windows has 2 renderings for gui. You probably know about this indirectly. For example the control panel is gdi+, so is the run box, and every single dialogbox in explorer. On the other hand you have the “new” like 13+ years old xaml which renders with true opacity and using triangles (without depth buffer)
  
  @endisn16h 2y
  
  it is bad, and silly
  
  @Agent1378 2y
  
  Answered to that above
  
  @endisn16h 2y
  
  hate to break it to you, but that wasnt me
  
  @Agent1378 2y
  
  I k ow but the answer would be the same😁
2. @ZgGPuo8dZef58K6hxxGVj3Z2 2y
  
  Windows? No it depends
@azizhakberdiev 2y

point of repeating frames?
1. @purplesyringa 2y
  
  IIRC, the spinner's speed oscillates, so perhaps that's the reason?
  
  @azizhakberdiev 2y
  
  that spinner undergoes same phase twice, they just placed same frames a second time
  
  @ZgGPuo8dZef58K6hxxGVj3Z2 2y
  
  No the same spinner is prerendered from the real spinners which is made in xaml. I have the source
2. @ilia_esmaili 2y
  
  There are tiny differences between the frames you highlighted
3. @batuto 2y
  
  Use it for frozen screen/no progress
4. @ZgGPuo8dZef58K6hxxGVj3Z2 2y
  
  They are not they are different just moving way slower
@ilia_esmaili 2y

Half life does this too
@azizhakberdiev 2y

It is the same thing like emoji set, they can write something like :lambda: . Unlike loadscreen spinner, it makes sense
@mpolovnev 2y

A while ago, I tried making a game and I stored a font as a tile set. They're doing the opposite - storing tileset as font
@mpolovnev 2y

Btw, I assume, the font renderer can draw it in any size and colour with neat sub-pixel borders. Re-using an existing thing is a great engineering practice!
@frayxrulez 2y

Using fonts for icons is quite a common practice nowadays
@Agent1378 2y

The thread is a year old but still...
@Agent1378 2y

Wtf, opensource world, wtf?
1. @purplesyringa 2y
  
  Ehh, it's not opensource world's fault, really. Windows provides just one UI, MacOS provides just one UI. Wayland's a protocol that's supposed to have lots of independent implementations. GNOME's ready, so you could argue it's no worse than what other OSes provide
  
  @Agent1378 2y
  
  I love internet😁
  
  @NanoSector 2y
  
  probono is anti Wayland and anti systemd, his posts are hilarious
@Agent1378 2y

And yes, I do understand the amount of work needed, but still...
@Agent1378 2y

This seems...classic https://gist.github.com/probonopd/9feb7c20257af5dd915e3a9f2d1f2277
@Agent1378 2y

@purplesyringa OK I ve read the above and now I have another question - are there any other "X replacement" projects? The ones that for example maintain full backwards compatibility but just eliminate all performance bottlenecks? Wayland seems to be another "systemd", did pottering wrote it also?
1. @purplesyringa 2y
  
  I don't think there's anything other than X and Wayland. Basically, Xorg's codebase is so damn ancient no one wants to touch it, so keeping backwards-compatibility *and* increasing performance is a ridiculously difficult project
  
  @Agent1378 2y
  
  Well isn't for a client desktop program X is just a collection of APIs? Why not just leave API as it is (well switching the way this API is called, direct via memory vs. Network is allowed) and rewrite the implementation?
  
  @purplesyringa 2y
  
  I think one of the reasons is that X protocol is inherently slow due to some design flaws, but I don't remember any specifics sadly
  
  @CcxCZ 2y
  
  I think you're both significantly overestimating the amount of effect the window/display system affects the latency of UI. Like - Gnome on Wayland renders most of it's desktop, including mouse pointer, as a single-threaded JavaScript application embedded into the display manager. So you can actually see the cursor jumping around and struggling to keep up. That's the kind of crap that's in there. X11 protocol does have it's downsides. But from what I remember, excluding stuff that has been addressed a decade ago it's: * no native support for multitouch touchscreens * compose stuff, i.e. rendering with the output of rendered windows — that kind of crap that Compiz did and has thankfully been largely forgotten about — is slower than on Wayland * few applications doing vsync, so you can spot tearing when moving stuff around * lack of access control anywhere, making keyloggers trivial (OTOH I don't believe in the Wayland approach either) And that's pretty much it to my knowledge.
  
  @Agent1378 2y
  
  Js for rendering desktop windows? Are they nuts.....chromium PC...
  
  @CcxCZ 2y
  
  Gnome devs? Yes. Circa gtk3 there was big split of gnome vs. other gtk/glib users downstream. And they went "fuck y'all" and it's been progressively getting worse. From my sources inside RedHat they are regarded as an especially insane caste even amongst their own ranks.
  
  @Agent1378 2y
  
  Its nice to know that I left ubuntu/gnome world when unity was first introduced.
  
  @CcxCZ 2y
  
  You have to remember: All Production Code Is Horrible https://www.stilldrinking.org/programming-suck FOSS has a rather small effect on that. What has more substantial effect is factoring things properly, eg. writing programs that do one thing and do it well. Guess what GUI developers do? The opposite of that.
  
  @Agent1378 2y
  
  Do one thing and do well - thats debatable. I always liked super advanced do-it-all software. If it was well written and well functioning.
  
  @CcxCZ 2y
  
  That's indeed worth having debate about. Because it's way more about composability, interfaces and general good engineering practices than forcibly restricting programs. Alas I can't commit to that right now.
  
  @Agent1378 2y
  
  Everything has its limits. High performance graphical desktop enviroment suitable for any kino of task - is outside of "do one thing and do well" paradigm
  
  @CcxCZ 2y
  
  I disagree there somewhat. Bad interfaces push desktop applications toward monolithic design.
  
  @CcxCZ 2y
  
  BTW that MIT-SHM extension is for using SHared Memory to transfer large chunks of data and has been in use by default since 90s
2. @purplesyringa 2y
  
  Also, I don't think it's like systemd in any reasonable sense. I'd even argue it's less of a "systemd" than Xorg. Wayland is just a specification that has lots of server implementations (GNOME, KDE, etc.) and client implementations (basically, every single GUI framework). That's unlike systemd and Xorg, which are large code bases which don't conform to any specification than their own code
3. @CcxCZ 2y
  
  https://www.divergent-desktop.org/blog/2020/10/29/improving-x/
4. @NanoSector 2y
  
  Ubuntu tried building Mir but it never took off
5. @RiedleroD 2y
  
  X was the systemd, Wayland is its replacement that tries to gobble up less functionality
@Dark_Lord_of_Debian 2y

So when your computer is lagging and someone asks you what it's doing, you can legitimately say "My computer is reciting the alphabet from A to Z."
@NanoSector 2y

It’s still active as a Wayland compositor project afaik
@Agent1378 2y

Did he fixed sound subsystem zoo ?is it working fine now?
1. @RiedleroD 2y
  
  pipewire works for everything :shrug:
@Agent1378 2y

But is it working for all programms? Or some need alsa, some neet pulse and when you install it all - gnome volume mixer stops changing volume😁
1. @RiedleroD 2y
  
  pretty sure the "gnome volume mixer" is pavucontrol, i.e. pulse audio volume control (don't ask about the u in pavu)
  
  @RiedleroD 2y
  
  and yes that still works with pipewire
  
  @sylfn 2y
  
  VolUme
  
  @callofvoid0 2y
  
  unit
  
  @RiedleroD 2y
  
  nope. the official name is "PulseAudio Volume Control"
  
  @sylfn 2y
  
  why not "easyeffects"?
  
  @RiedleroD 2y
  
  …why easyeffects
@Agent1378 2y

Nice

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The Windows Boot Spinner Is a Font, Not an Animation

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