alt.hn

6/13/2025 at 2:04:35 PM

Show HN: Tattoy – a text-based terminal compositor

 https://tattoy.sh

by tombh

6/13/2025 at 5:03:04 PM

This looks really cool, I'd like to give it a go. The idea of taking a screenshot of the terminal and then parsing that to determine the true colour support is definitely novel, though perhaps so, because for me I can't get it to work. Are there any debug flags I can enable?

So far it was able to take the screenshot correctly (https://ibin.co/8kaRr8TIanv2.png), however the parsing of that fails with the non-descript "Palette parsing failed." error.

Edit: enabled tracing at got this: https://paste.ee/p/ZyNxG9FK

by tfsh

6/13/2025 at 5:45:34 PM

> The idea of taking a screenshot of the terminal and then parsing that to determine the true colour support is definitely novel,

A better way to do this is to send `OSC 1 0 ; ? ST` (query foreground color), `OSC 1 1 ; ? ST` (background color), then `OSC 4 ; {n} ; ? ST` where {n} is the nth XTerm color.

See: https://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h4-O...

by shiomiru

6/13/2025 at 5:53:28 PM

OMG really!? That link is blocked for me for some reason. If that OSC code is widely supported it's going to make things sooooo much easier.

by tombh

6/13/2025 at 10:02:05 PM

It’s very widely supported from my experience. This is how asciinema captures terminal palette.

by ku1ik

6/13/2025 at 9:15:30 PM

It’s supported by any xterm compatible terminal emulator. But like with most things in this domain, expect plenty of edge cases where it should work but doesn’t.

by hnlmorg

6/13/2025 at 5:52:22 PM

Thanks for trying it out. It looks like either your terminal or screenshotter isn't faithfully rendering the pure red marker column (it's needed for calibration in the parser). The red should be #ff0000, but the screenshot is using #ea3323. I've made a Github issue to keep track https://github.com/tattoy-org/tattoy/issues/98 If you can add more details it'd really useful, I'm sure there'll be more people like you.

by tombh

6/14/2025 at 11:03:43 AM

Maybe that's night mode (or whatever your DE calls it)?

by mkesper

6/14/2025 at 12:29:17 PM

Interesting, I'd never thought of that.

by tombh

6/13/2025 at 3:46:49 PM

I see you added then removed Windows from your Release plan:

https://github.com/tattoy-org/tattoy/issues/42

So, it is supported or not? Looks great by the way.

by TheSilva

6/13/2025 at 3:54:12 PM

Thank you.

Windows is supported, I've tested it in Windows Terminal and Powershell. I removed it that issue from the release plan because not all the subtasks are finished yet. And more broadly speaking I just haven't had much feedback from Windows users. For example I haven't managed to get GPU passthrough working in my Windows VM so haven't actually been able to test shaders yet.

by tombh

6/25/2025 at 4:52:25 PM

If you need Windows beta testers, I'd be happy to volunteer.

by globnomulous

6/14/2025 at 5:40:37 AM

On which hypervisor?

by PeterStuer

6/14/2025 at 12:11:29 PM

QEMU. I'm on Asahi Linux (Linux for M-series Macs) and we've only just got virtualisation support in the last few months.

by tombh

6/13/2025 at 4:24:20 PM

Tattoy manages its own scrollback buffer (like say `tmux` does), and so can therefore also provide its own scrollbar.

this raises two questions: doesn't every (gui) terminal do that?

what happens if i use tmux inside tattoy?

btw: do you have examples of light themes?

by em-bee

6/13/2025 at 4:38:38 PM

Yes, every GUI terminal manages its own scrollback buffer. The reason that Tattoy and tmux have their own buffers is because they are essentially terminal emulators themselves. For instance a terminal emulator may have 10 tmux panes and it should of course be possible to view the history of each one. Tattoy manages its own scrollback because that's the only way to make the scrollback available programatically to other processes, like the minimap for example.

Interestingly Alacritty in the beginning didn't natively support scrollback because it wanted to hand-off that concern to multiplexers like tmux. So there's precedent for terminals emulators not having to support scrollback.

tmux should work fine in Tattoy, the only thing to be aware of is that Tattoy would then handle input, like for scrolling etc, so some events may not reach tmux, in which case you could make some custom tmux keybindings that Tattoy doesn't recognise. It's also worth noting that Tattoy recognises the so-called "alternate screen" state that tmux controls its host with. And in such cases Tattoy forwards scrolling events to the underlying process, like say the mouse scroll wheel.

I don't have any light theme examples yet. It should mostly just work though.

by tombh

6/13/2025 at 6:40:35 PM

my first attempt at using a light theme with gnome-terminal gets me white on white either in the prompt or on the commandline itself. don't have time to debug that now though.

what i was wondering is how the scrollback of tattoy and tmux would interact. normally when you use tmux the terminals scrollback remains unused (which is why alacritty devs thought they don't need their own). but from how tattoy uses the scrollback, i feared that tmux would actually interfere with some tattoy functionality. that's what i am curious about.

by em-bee

6/13/2025 at 6:54:11 PM

Oh white on white isn't good, sorry about that, I'll look into it.

I also have some ideas to make Tattoy into a multiplexer. I really like the idea of desaturating and fading unfocussed panes.

by tombh

6/14/2025 at 2:04:10 PM

I especially like the idea of evolving the protocol. Just because the text first ui is a great idea doesn’t mean we achieved perfection with ansi escape codes.

by sevensor

6/13/2025 at 2:32:05 PM

This is brilliant, thanks for making public and best wishes

by nerflad

6/13/2025 at 3:57:37 PM

I'd probably run cmatrix for looks or maybe htop on the background. Also, Rick-rolled in the screenshot.

by otterpro

6/13/2025 at 3:55:04 PM

It seems like what you really wanted was a streaming SVG renderer and not a VTE.

I kind of like that idea.

by msgodel

6/13/2025 at 4:04:34 PM

How do you mean? I'm actually not a fan of terminal image protocols like Sixel and Kitty's image protocol. I value the constraints of only being able to use text. I feel that in some ways when we venture into real graphics the soul of the terminal is lost.

by tombh

6/13/2025 at 4:07:02 PM

Maybe I'm confused, I guess this is more an aesthetic thing than a practical thing. I just see VTEs as a minimal UI API for software.

by msgodel

6/13/2025 at 4:14:45 PM

I'm curious about your minimal UI API idea.

by tombh

6/13/2025 at 7:07:50 PM

Because why shouldn't my terminal be the largest consumer of memory on my PC?

by cenobyte

6/13/2025 at 7:11:30 PM

I paid for 32GB, I’m gonna use 32GB.

by tines

6/14/2025 at 10:14:16 AM

Interesting project. You might check out Arcan (https://arcan-fe.com/) if you've never heard of it. (EDIT: I see author recently added a link: https://github.com/tattoy-org/tattoy/blob/main/website/conte... )

A couple of points related to contrast ratio management:

- The Mynex answer here is very informative: https://stackoverflow.com/questions/596216/formula-to-determ...

- The "limit/bound" on the contrast ratio has a "polarity" (a +- sense). At least for "text", in almost every font there are many more background pixels than foreground pixels. So, for example, your human eyes can tolerate a lower text cell fg-bg contrast with a dark background color for the text cell on an all-black background than they can for a dark foreground color on an all-black background. Part of this relates to "shared discrimination work" that the outside-the-text cell background pixels are doing. So, really "ratio" of just two things is somewhat of an oversimplification.

- XTerm OSC 4 may have a very limited ability to probe the color palette. At least on `st` I can only see default foreground, background and cursor colors, not the full 16-color palette. This mostly just amplifies the point elsethread by @hnlmorg.

- At least until more recent ssh's, default configs on Linux would pass through all "LC_*" environment variables. So, if you adjust your shell rc/configs to key off of, say, $LC_THEME having, e.g., "light" or "dark" in them, you can perhaps re-polarize everything with a much lower tech solution. I do this all the time as I like to run some terminals with a black background and some with a white background. (Paper white black & white displays were all the rage in the 90s, but these days "color hackers" seem to prefer dark backgrounds. I have theories as to why, but it's pretty off topic.) https://github.com/c-blake/lc configs have more fully fleshed out examples, and hey, you might also like that color-ls. (And I'm aware of the ancient & to my mind ugly 1980s ideas of "stuff everything into $TERM and parse it apart again". Security concerns may push us back that way.)

by cb321

6/14/2025 at 12:10:25 PM

Wow thanks for all this insight. I'd never considered the idea that the ratio of foreground to background pixels impacts the visual perception of text readability. Of course that totally makes sense now that I think about it. Do you know if that's been considered anywhere in the WCAG standards?

I'm thinking that I'm going to support both palette screenshotting and OSC 4.

I've certainly seen those LC_* variables before but I don't seem to have them right now in my current shell. Are you saying that they can be another source of the true colour values of the palette indexes?

by tombh

6/14/2025 at 2:24:46 PM

AFAICT, this "number of pixels" (as well as the outside-the-cell pixels) effect is one of those "obvious as heck if you experiment on yourself with barely any science or even just contemplate it" things that somehow winds up ignored in standards. I'd love to be wrong, though.

The screenshotting is surely more portable.

I was not saying LC_* are a source of color values, though a terminal could surely do that as a way to export this data to its first shell without the clunky stdin/out protocols for OSC4. For example, I believe one variant of rxvt/urxvt used to export COLORFGBG. I would even say (LC_FG LC_BG LC_COLOR0..15 LC_CURSOR, etc) is an ok idea. One downside is a user could change the values since environment variables are very much not "read only", but that is sort of "on them" for fooling subprocesses "on purpose".

I was mostly lamenting that ssh server configs are moving toward making it hard(er) to "pass through" this kind of environment variable-driven setup. Something people often overlook in this general problem space is making whatever protocol they come up with also "work through to shells beyond one (or more) ssh hops". So, the LC_COLOR<N> idea would have been "more fabulous" 5..10 years ago when I would have anticipated "this will usually work". Maybe it could still be easier for some than OSC4.

Anyway, big topic with half century of history and hard to be brief.

by cb321

6/14/2025 at 2:59:06 PM

> XTerm OSC 4 may have a very limited ability to probe the color palette. At least on `st` I can only see default foreground, background and cursor colors, not the full 16-color palette. This mostly just amplifies the point elsethread by @hnlmorg.

What st version? For me, 0.9.2 prints the entire color cube with

    for n in `seq 0 255`; do printf '\033]4;%d;?\033\\' "$n"; done; read
(although unsurprisingly, it's subtly broken: I sent ST, but the responses are terminated with BEL...)

by shiomiru

6/14/2025 at 5:21:16 PM

You are completely right. It totally "works" now { scare quotes as per your termination comment.. ;-) . I guess xterm terminates in the answer back with whatever the client sends in the request. It's funny how now things began as DEC vtXX emulators and now things are "xterm emulators". }

Thank you for correcting the record, @shiomiru!

by cb321

6/13/2025 at 3:20:04 PM

Oh wow, now I can finally have terminal that creates fire effects the faster I type! (if I ever get the time to make the plugin)

Is there anyway for plugins to interact with shaders?

by grandma_tea

6/13/2025 at 3:29:27 PM

Intenser flames the more you type, great idea!

Plugins can't currently get the shader pixels. But that's just because I haven't added them to the plugin protocol yet. But interestingly shaders actually have access to the terminal contents in the form of a pixelated version of the text. And the mouse and cursor position too. So maybe there's something you could do purely in a shader.

by tombh

6/13/2025 at 2:21:43 PM

Nice idea, I like the out of the box thinking on display.

by pacifika

6/13/2025 at 4:35:26 PM

This looks amazing. Well done.

by MatthewPhillips

6/13/2025 at 3:53:11 PM

Can it run doom?

by ainiriand

6/13/2025 at 3:57:02 PM

There is actually a Shadertoy for Doom! https://www.shadertoy.com/view/lldGDr So in theory Tattoy could run it, the only thing is that it doesn't currently support extra buffers and that Doom shader needs 5 of them.

by tombh

6/16/2025 at 12:34:21 PM

Thank you for (1) sharing a fascinating project that has nothing to do with "AI," (2) mentioning not once, anywhere, even in the repo docs (as far as I can tell) that Tattoy is written in Rust, and (3) not writing docs that look and sound like ad copy intended to woo VCs or outcompete other software packages.

Seriously, this is high-quality work (as far as I can tell -- though it is way outside of my area of expertise) and the presentation is a model of class and taste. This is what I come to HN for, and it's a badly needed shot of motivation to start, finally, working on my own terminal-related project.

by globnomulous

6/13/2025 at 5:49:55 PM

SUPER COOL

by gfalcao

6/13/2025 at 6:12:33 PM

Id probably have an easier time finding out about this project if it didn't full screen auto play videos as I scroll?

by djaychela

6/13/2025 at 6:17:27 PM

I didn't intend for the videos to be fullscreen. They need to be small in order to save bandwidth. They're certainly autoplaying (to replicate GIF behaviour), but maybe there's a bug with them going full screen. What browser are you using?

by tombh

6/13/2025 at 7:16:58 PM

Firefox on ios. They are full the screen and auto play as soon as I get to whatever part of the page they are on.

Tbh I think giving the user voice as to whether to play them would be a better experience anyway, but it's really unusable as is.

by djaychela

6/13/2025 at 8:38:54 PM

I get the same experience on iOS using the OS web view - my guess is because iOS (and maybe android?) don’t typically play videos in “windowed mode” (for lack of a better term) outside of eg Google video snippets which seem to do some hacky stuff to keep you “in Google” while watching.

Regardless of the fullscreen aspect, and understanding you wanted something jiff-like, I also don’t care much for auto playing video. It doesn’t matter too much if it’s small (as this is intended), silent (as terminals typically are), and doesn’t hoist control of my browser.

Edit: forgot to say that this looks really cool, great work!

Editedit: also forgot to mention that the thumbnails are super blurry on my phone, and after the one video took control of the screen, all the other thumbnails went black.

by phatskat

6/14/2025 at 12:16:16 PM

Thank you!

Thanks to another commenter I've added `playsinline` to the video tag, so hopefully that fixes it.

What do you think a suitable size for all these video/gif assets is? I'd be totally happy to move to .gif or animated .webp but I can seem to get they're filesizes down to a reasonable size.

by tombh

6/14/2025 at 3:19:56 PM

Totally sorted the usability for me. TBH I'm not that fussed about data sizes provided it's not mental but most importantly I can now actually -read- what you've done!

by djaychela

6/14/2025 at 1:45:14 AM

I think you just need to add "playsinline" to your videos so that they play inline on mobile devices instead of fullscreening.

    <video autoplay loop muted playsinline>
instead of your current

    <video autoplay loop muted>
cool project :)

by eieio

6/14/2025 at 12:28:10 PM

Thank you, I added it! Let's see if it helps.

by tombh

6/14/2025 at 1:15:17 PM

looks good for me on mobile now!

by eieio

6/13/2025 at 3:21:07 PM

This is like the pinnacle of term ricing, I love it

by ramon156

6/13/2025 at 8:40:54 PM

Ricing?

by phatskat

6/13/2025 at 9:07:19 PM

Ricing means making your setup pretty with extensive customization.

https://www.reddit.com/r/unixporn/ https://github.com/fosslife/awesome-ricing

by efilife

6/13/2025 at 10:51:49 PM

Ah I see, but why that term?

by phatskat

6/14/2025 at 3:48:13 AM

A 'ricer' is a small Japanese sports car (e.g. Subaru WRX or Mitsubishi Evo) souped up or given fancy paint job and spoilers etc). Rice for the country of origin.

by emmelaich

6/14/2025 at 5:57:26 AM

To further elucidate, it's a contraction of "rice burner," suggesting the vehicle uses rice as fuel.

https://en.wikipedia.org/wiki/Rice_burner

As Wikipedia relates, "rice burning" refers to a technique of clearing the roots of a rice paddy with fire after a harvest, a bit like slash-and-burn in forestry, and "rice burner" was indeed used as a slur against East Asian people in the second quarter of the twentieth century.

However, simlevesque is not wrong—the term is not usually used in the modding community in a bigoted manner, despite its obvious past association with bigotry. Rather, because Japanese cars were affordable, modding them was seen as cheap, so a car enthusiast with a modded Japanese car was considered a wannabe or imposter, especially if the modifications made their car superficially resemble traits associated with expensive American and European muscle cars, such as extra tailpipes or a louder engine. The ultimate vehicle for these modding jobs was the Honda Civic, which was plentiful and had lots of kits made for it; when Honda released the high-performance Type R edition street racers were quick to expand the "R" to "Rice" (only a mild alteration of the intended meaning, which was something like "Racetrack-worthy.")

In computing, the jargon of "ricing" or "being a ricer" carries a slight air of self-deprecation because front-end customization enthusiasts recognize their endeavors are shallow—many of them can barely administrate the Arch Linux installs they've set up, and almost none of them actually do any programming. The heart of this community remains 4chan's /g/ board, though arguably Reddit owes its entire existence to such people.

by rhet0rica

6/13/2025 at 11:46:24 PM

Pretty sure it’s racist (or at least pejorative) in origin referring to the asian car customization / import scene.

by notnmeyer

6/14/2025 at 2:56:17 AM

It's the term used by the community.

by simlevesque

6/13/2025 at 9:13:12 PM

> Firstly it solves the age-old problem of low-contrast text, like when you `ls` a broken symlink and the red background colour is too near your current theme's foreground colour.

That’s already a solved problem. You use a terminal theme that produces high contrast against all the 16 terminal colours.

Plenty of good themes exist.

The bigger problem, in my opinion, is software that uses 8 bit or 16 bit colour ANSI codes and thus overrides your terminals theme. Personally I consider this rude behaviour but I know there is a subset of HN that disagrees with me here.

by hnlmorg

6/13/2025 at 10:13:05 PM

My understanding is it ensures proper contrast for all cells regardless of the type of fg/bg color (palette, 8 bit, 24 bit). So if a program uses 24 bit fg color and a bg from palette (or a default one) it would still preserve the contrast. (haven’t tested, just my impression from reading the docs)

by ku1ik

6/14/2025 at 9:52:13 AM

That’s my point though. People abuse the other palettes.

This is why we can’t have nice things.

by hnlmorg

6/14/2025 at 12:25:10 PM

I've never actually made a palette, but it just doesn't seem practical to me to expect theme creators to always find a contrast-safe 16 colour palettes. I would imagine that it even seriously restricts the range of themes that can be made. I can imagine that such a thing is possible for smaller palettes like say 3 colours though, but then that's not actually useful for UIs.

I think the fact is that small palettes come from the days of lower resources, not from efficient program design.

by tombh

6/18/2025 at 10:43:27 AM

There are already plenty of 16-colour palettes available. Literally thousands of them. And it takes all of about 10 seconds to search for “$TERM theme”.

The problem isn’t the lack of themes. The problem is CLI/TUI developers who think their random pet project is more important than their users accessibility needs and colour preferences.

by hnlmorg

6/13/2025 at 5:14:51 PM

[dead]

by curtisszmania

6/14/2025 at 3:06:59 PM

[dead]

by b0a04gl

6/14/2025 at 5:38:53 AM

Now we get Rickrolled in the terminal. Great! /s.

by PeterStuer

6/13/2025 at 8:07:37 PM

[flagged]

by apwell23

6/13/2025 at 9:59:06 PM

[flagged]

by d4rkp4ttern

6/14/2025 at 8:29:49 AM

Well I didn't either, so join the boat I guess :)

by ctxc

6/13/2025 at 11:16:56 PM

Not sure what you mean by "supposed to know". There's no universal "tech syllabus", so there's nothing (or everything?) that you're supposed to know.

But if you're asking is this a term in common usage in software, then yes, it is.

by azornathogron