SVG started as an open competitor to Shockwave/Flash Player and also an application format for PDAs. It almost got networking support once.
bawolff · 5m ago
> It almost got networking support once.
SVG support full javascript. It has networking support.
(In web browsers the <img> tag allows only restricted subset, butbyou get the full thing with iframe)
echelon · 2h ago
Too bad nothing has ever come close to replacing the SWF format.
You could pack so much into a single binary distributable media file. Games, videos, websites, infographics, tools, chat rooms.
SWF was brilliant and it should have thrived.
qwertox · 1h ago
If it weren't for Adobe's crappy support of the player, I would agree, but they did much more harm than good with it. It was a massive attack surface and they didn't care about closing their zero-day drive-by exploits in a sensible timeframe.
Also they were basically the founders of persistent fingerprinting via Flash cookies.
So no, thank you, I'm more than happy it didn't thrive more than it already did.
unleaded · 2h ago
absolutely. really is strange that you used to be able to download a music video in less than 2-3mb with lossless video quality, but now that's not really a thing anymore. I feel like if Adobe didn't get greedy and encourage its use for absolutely everything (and/or web standards got up to speed faster) people wouldn't wouldn't approach talking about Flash with the 10-foot pole they often do today (as a platform—not how everyone talks about how much they loved flash games)
comex · 1h ago
What do you mean by “HD music video”? If you mean a literal video, then today’s video and audio codecs are more efficient than what Flash used, not less. If the music videos were that small then they must have given up a lot in quality. If you mean a Flash vector animation, then that’s different of course, but that doesn’t describe a typical music video.
kccqzy · 48m ago
Conventional video codecs are also pretty good at compressing animations. I once made a multi-minute animation of a plane taking off and H.264 compresses it to hundreds of kilobytes.
unleaded · 43m ago
yes i mean vectors, of course theres some cheating to reach that figure ;)
viraptor · 2h ago
People loved the games, but not the super custom flash based menu that requires a loading bar and works totally different and slightly janky on each website.
kccqzy · 51m ago
That's because people have more bandwidth today and therefore videos online are higher quality now. You can easily transcode a music video to 3MB using modern codecs (and even not so modern ones like H.264), and it will look somewhat worse than typical online video sites but still pretty good.
ToucanLoucan · 43m ago
Thank fuck it didn't. I can't fathom how quickly the obnoxious advertiser industrial complex would've grabbed hold of that and invented whole new genres of shoving products in our collective face.
koakuma-chan · 1h ago
Huh? SVG stands for scalable vector graphics.
FateOfNations · 1h ago
Functionally, it can do a lot of the same things as SWF/Flash. Can do animations (see article) and it's scriptable using JavaScript for interactivity.
As for the first link, I immediately had to come up with a way to click on the warheads programmatically. I saved the world! :D
Natsu · 33m ago
After reading the headline and before reading the article, I thought it'd be something like a visual hash of readme files, as an easy way to see if anything had changed between releases.
I was thinking that might be a useful thing for people to spot when a ToS, EULA, etc. changed since those are long documents that frequently get sneaky revisions.
Theodores · 2h ago
That checkbox feature in the Tube Map is awesome. I need to up my SVG game.
That said, OP's SVG trick may be a smarter choice if the content is a terminal capture.
c-hendricks · 3h ago
If you're going this route of adding a straight up video (which isn't bad!) it helps to edit the readme directly on GitHub. That way they're uploaded to githubusercontent (or whatever the domain is) and not taking up space in your repository.
hbn · 2h ago
Were people doing that other option?
The idea of committing a video to your repository for a PR seems silly. Every PR adds a new video to the codebase? Do you make a PR to prune them every once in a while?
aziaziazi · 40m ago
> Every PR adds a new video to the codebase
Git commits only differences with the precedent commit, not the entire repository. Therefore the video is only committed once as long as that video doesn’t change.
pamelafox · 2h ago
The nice thing about videos is the play/pause/slider UI. Some platforms do add play/pause explicitly to GIFs, using some JS, but as far as I know (and you would know more), that's not built into browsers yet. That's been one of the reasons I often end up using videos instead.
When I've personally animated SVGs for use in RevealJS presentations, I tend to use CSS animations that I could control with JS if I wanted.
not2b · 2h ago
An animated GIF is essentially a video with a large number of restrictions and poor compression compared to an actual video. Often sites convert animated GIFs to videos because the result is smaller and works better.
kzrdude · 2h ago
If this gets widespread use, browsers will catch up and in 5-10 years we will have pause buttons! ;)
justsomehnguy · 1h ago
Meanwhile we are still have a stupid overlay controls because 20 years ago it was an iframe for an ActiveX control.
ordinarily · 14m ago
I used SVG animations (and sites like https://www.svgator.com/) long before stuff like Rive or Lottie was commonplace. SVG animations are great.
yawnxyz · 3h ago
It's pretty unintuitive that you can just copy text straight from an animation, but that's the neatest part of this!
ndr · 2h ago
What would be wild is if the animation pauses on mouse-over.
It's quite a challenge for copy-paste to be useful when the terminal is scrolling.
exabrial · 1h ago
I freakin love SVG. Someday I hope we just end up with a browser standard:
* pluggable execution engine/memory model (WASM, JVM, CLR, etc)
* SVG output (binary or text)
From there, the developer can choose whatever model he wants to display a "page", no longer be limited to the Document Object Model.
lpghatguy · 36m ago
Once upon a time, Flash, Java, Silverlight, ActiveX, etc. ruled the web.
I think the world is _much_ better off today, with a common language and platform. I don't think those big third party runtimes could survive in the browser in today's threat environment.
pjc50 · 3h ago
"SVG is inherently animated" is new to me, and now I'm going to spend my time on the bus thinking what might be done with that. Does it support infinite loop?
snackbroken · 3h ago
> Does it support infinite loop?
Yes, by setting the repeatCount or repeatDur attribute of the <animate> tag to "indefinite". Notably, since <animation> tags effect individual attributes and not the image as a whole, different parts of the image can be on different animation cycles and don't have to add up to some small common multiple.
For some sick reason now I really want to convert some SVG architecture diagrams to movies which reveal the nodes in a dramatic anime battle style with zoom-ins, freeze frames, pulsating lines around, etc.
x187463 · 3h ago
Well, this is cool. I'll have to see how it handles the sorts of effects I show in the README at https://github.com/ChrisBuilds/terminaltexteffects. I don't know much about SVG but anything that attempts to actually store the text is going to create a very large amount of data. I'll try it for fun.
layer8 · 3h ago
What does “Github supports these” mean here? Isn’t it the browser that has to support them?
c-hendricks · 3h ago
Github could (should) be doing some sanitation of the HTML included in the readme, so they absolutely could be removing some nasty things SVGs support
layer8 · 3h ago
But it’s just an image link to some SVG file. No HTML involved, only a Markdown image link that GitHub will render as an HTML <img src="…"/> element. The actual SVG file linked to isn’t even necessarily hosted by GitHub.
paulryanrogers · 2h ago
They could follow the img src and deny any which are harmful. Or even replace them with a sanitized copy.
layer8 · 1h ago
This is nonsense. The actual file at the URL could change at any time. No system is doing something like that if it isn’t serving the file itself.
And, getting back to the original point, you wouldn’t be worrying that GitHub doesn’t “support” a URL that happens to point to a file of a particular subformat that the URL itself doesn’t disclose.
Evidlo · 16m ago
Doesn't Github already replace externally linked images with its own cached version when rendering out Markdown files?
matths · 4h ago
I like little TIL posts like this, introducing new tools and sharing first-hand experiences with them. Working around restrictions (like using animations in Github Markdown) leads to this kind of creative stuff.
I looked at the resulting SVG https://koaning.io/posts/svg-gifs/parrot.svg and realised that a lot of inline SVG elements are used within inline SVG within..the SVG. I've never seen that before. So thank you very much for sharing.
Aardwolf · 3h ago
So one could make a quine: an animated SVG that shows its own source code being typed into a text editor
xml · 2h ago
A word of caution: There are SVGs which can freeze a page, so make sure that you do not link to any third party SVGs. This is a known bug, but both the Google Chrome and Mozilla team do not want to fix it.
Here is an evil example SVG for demonstration.
DON'T CLICK THIS LINK UNLESS YOU WANT TO RISK CRASHING YOUR BROWSER!
Crash a single page or even the whole browser isn't really a security problem though. In fact, there are so many ways to freeze the whole tab or even browser ui with build-in function if you apply it way too many times. (For example, a long chain of blur filters will make the chrome ui non responsive because the render time will skyrocket.)
Although if the affect area does escape the tab, the issue will have higher priority because that would be annoying to user.
anyone knows if it's possible to convert gif to svg or mp4? for instance, I'd like to share a screen recording in svg. It might sound like a dumb idea, maybe it is
jackbrookes · 1h ago
just record as mp4 in the first place, gif has limited colour palette, low frame rate and poor compression
nico · 2h ago
This is very cool and useful for the readmes. Thank you for sharing
I’m wondering what other applications this could have
At least every CLI/terminal tool could use it to showcase their application
sevensor · 4h ago
Cool, but I’m not clear on why you have to upload and then download your cast file to make this work.
7h3kk1d · 4h ago
I don't think you do. The --in param on svg-term-cli worked for me locally.
jodacola · 10m ago
Don't need to upload. I just tested this out because I didn't want to have to upload to asciinema:
$ asciinema rec test.cast
<do stuff in the terminal then ctrl-d>
$ cat test.cast | svg-term --out=test.svg
And voila, no upload needed.
perching_aix · 4h ago
That is terrifying. Does look great though!
I thought people were just doing GIF color palette optimization with ffmpeg instead.
hnlmorg · 3h ago
Why “terrifying”?
Springtime · 2h ago
I think some have only heard bad things about SVG exploits but perhaps aren't familiar that IMG embedded SVGs (like those used in Github readmes) don't carry those risks as they're restricted from running Javascript, external content or videos.
hnlmorg · 2h ago
Ahhh that would make sense. Thanks for the explanation
chrisweekly · 2h ago
Obligatory mention of Sarah Drasner's fantastic (and somehow still valid and eye-opening in 2025) "SVGs Can Do That?" talk from 2017:
https://slides.com/sdrasner/svg-can-do-that
westurner · 2h ago
Tools for making animated SVGs from terminal recordings:
Last commit ~6 years ago. Does not appear to be any viable forks either.
Fortunately, I use nix to manage my system which sort of forces me to inspect the maintenance history of projects. Better than blindly installing `npm` packages in global namespace.
asciinema on the other hand is very interesting. Seems I can do without the svg aspect here, but something to keep in mind (svg animations).
jlarocco · 1h ago
Did you hit a bug or security issue that's blocking you from using it?
oblio · 2h ago
SVG is another proof of worse is better. Nothing should be animated via JavaScript, at least not imperatively.
0x457 · 2h ago
but SVG embeds ECMAScript...
oblio · 2h ago
Fairly sure there are SVG subsets that can be used. Not all of them embed JS.
And that wasn't my point. SVG supports animation primitives. No need to animate through JS.
https://upload.wikimedia.org/wikipedia/commons/9/9b/SMIL_mis... missile command clone
https://upload.wikimedia.org/wikipedia/commons/1/13/London_U... tube map
https://upload.wikimedia.org/wikipedia/commons/4/49/Rolling_... rolling shutter animation
SVG support full javascript. It has networking support.
(In web browsers the <img> tag allows only restricted subset, butbyou get the full thing with iframe)
You could pack so much into a single binary distributable media file. Games, videos, websites, infographics, tools, chat rooms.
SWF was brilliant and it should have thrived.
Also they were basically the founders of persistent fingerprinting via Flash cookies.
So no, thank you, I'm more than happy it didn't thrive more than it already did.
As for the first link, I immediately had to come up with a way to click on the warheads programmatically. I saved the world! :D
I was thinking that might be a useful thing for people to spot when a ToS, EULA, etc. changed since those are long documents that frequently get sneaky revisions.
Bookmarked!
That said, OP's SVG trick may be a smarter choice if the content is a terminal capture.
The idea of committing a video to your repository for a PR seems silly. Every PR adds a new video to the codebase? Do you make a PR to prune them every once in a while?
Git commits only differences with the precedent commit, not the entire repository. Therefore the video is only committed once as long as that video doesn’t change.
When I've personally animated SVGs for use in RevealJS presentations, I tend to use CSS animations that I could control with JS if I wanted.
It's quite a challenge for copy-paste to be useful when the terminal is scrolling.
* pluggable execution engine/memory model (WASM, JVM, CLR, etc)
* SVG output (binary or text)
From there, the developer can choose whatever model he wants to display a "page", no longer be limited to the Document Object Model.
I think the world is _much_ better off today, with a common language and platform. I don't think those big third party runtimes could survive in the browser in today's threat environment.
Yes, by setting the repeatCount or repeatDur attribute of the <animate> tag to "indefinite". Notably, since <animation> tags effect individual attributes and not the image as a whole, different parts of the image can be on different animation cycles and don't have to add up to some small common multiple.
https://developer.mozilla.org/en-US/docs/Web/SVG/Reference/E...
So not only do you get all the animation support from the attributes, you can fill in anything you need from scripting.
Yes it does.
https://www.w3schools.com/graphics/svg_animation.asp - Has some examples, you may need to refresh to see some of them (ones that don't repeat) in action as you scroll down the page.
And, getting back to the original point, you wouldn’t be worrying that GitHub doesn’t “support” a URL that happens to point to a file of a particular subformat that the URL itself doesn’t disclose.
Here is an evil example SVG for demonstration.
DON'T CLICK THIS LINK UNLESS YOU WANT TO RISK CRASHING YOUR BROWSER!
https://asdf10.com/danger.svg
Although if the affect area does escape the tab, the issue will have higher priority because that would be annoying to user.
I’m wondering what other applications this could have
At least every CLI/terminal tool could use it to showcase their application
$ asciinema rec test.cast
<do stuff in the terminal then ctrl-d>
$ cat test.cast | svg-term --out=test.svg
And voila, no upload needed.
I thought people were just doing GIF color palette optimization with ffmpeg instead.
asciinema2svg: https://github.com/thenets/asciinema2svg
termsvg: https://github.com/MrMarble/termsvg
/? terminal svg: https://hn.algolia.com/?q=terminal+svg
/? svg animation: https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...
https://github.com/marionebl/svg-term-cli/commits/master/
Last commit ~6 years ago. Does not appear to be any viable forks either.
Fortunately, I use nix to manage my system which sort of forces me to inspect the maintenance history of projects. Better than blindly installing `npm` packages in global namespace.
asciinema on the other hand is very interesting. Seems I can do without the svg aspect here, but something to keep in mind (svg animations).
And that wasn't my point. SVG supports animation primitives. No need to animate through JS.