Support ligatures in terminal

[Tyriar]

Regresses with performance improvements in terminal's renderer #33954

[Mohamed3on]

Hi! is there any timeline for this feature?

[Tyriar]

Nope.

Here's the upstream issue xtermjs/xterm.js#958

[coreh]

Would be really nice if there was a setting to re-enable the old terminal rendering until all the issues with the new terminal are resolved (blurriness, ligatures, emoji). 😕

[MPV]

It seems there is now an xterm.js plugin for ligatures support:
https://github.com/xtermjs/xterm-addon-ligatures

How can we get it into vscode?

[Tyriar]

@MPV it would have to be built into the core, the main thing that needs to happen now is to evaluate how much weight the addon would add to the VS Code distributable.

[cziem]

This is how my vscode term looks like, I want it to look like this:

[Tyriar]

@Phavor I don't think your issue is about ligatures but rather your powerlines setup https://code.visualstudio.com/docs/editor/integrated-terminal#_can-i-use-powerline-fonts-in-the-integrated-terminal

[cziem]

@Tyriar I fixed though. Thanks. This line did the job "terminal.integrated.fontFamily": "'Fira Code iScript'"

[FelikZ]

any news on it? I believe this is the last thing is missing for terminal to render everything proper

[wolf99]

Just tried Cascadia Code font in the integrated terminal... ligatures not present 😢

[jhpratt]

I see that there's a way to do this via an extension that modifies VS Code's internal files. Would it be possible to add a checkbox in settings that toggles this itself? @Tyriar

[Tyriar]

@jhpratt that's what it would do eventually, the remaining work here is slimming down the ligatures xterm.js addon to bare essentials and test/include it. I don't have time to do it right now due to other priorities though.

[Geobert]

Is this bug why I got this in vscode:

instead of:

(using this font https://github.com/adam7/delugia-code)?

[Tyriar]

@Geobert probably caused by xtermjs/xterm.js#1709 or xtermjs/xterm.js#942, ligatures are different to emoji.

[Tyriar]

Got a bunch of questions about ligatures when tweeting about the WebGL renderer so I'll give an update here. Here's the remaining work to do on this:

• xterm.js
  • Integrate xtermjs/xterm-addon-ligatures into the xtermjs/xterm.js repo, this will enable automated publishing and ensure tests continue to pass Merge ligatures addon into core repo xtermjs/xterm.js#2726
  • Hook up ligatures into the demo
  • Set up some puppeteer tests that verify on all renderers (dom, canvas, webgl) that ligatures are working
  • Slim down the dependencies as much as possible
  • Leverage web font API
• vscode
  • Integrate xterm-addon-ligatures such that the addon code is not loaded if ligatures is off, add the setting, etc.

[Tyriar]

Giving it another shot in #232829

[Tyriar]

Looks like this should land as a preview feature in the November release! #232829

Enable it with "terminal.integrated.fontLigatures": true and please report any problems you see. It should be in tomorrow's Insiders build.

[pattrickrice]

Wow amazing!

[iwangbowen]

Finally

[joshlawton]

Just to confirm, this setting only accepts a boolean value and does not enable explicit font-feature-settings like ss01 or cv69? That is, even if terminal.integrated.fontLigatures is true, the font may not necessarily match the style sets and character variants enabled in the editor?

// settings.json

// Works
"terminal.integrated.fontLigatures": true

// Won't work as expected at this time?
"terminal.integrated.fontLigatures": "'calt', 'liga', 'ss19', 'cv69'"

Compare editorOptions.ts to terminalConfiguration.ts.

[Tyriar]

@joshlawton yes it's all or nothing right now. If someone can figure out how to pass that information on to an OffscreenCanvas it should be trivial to add the support: https://developer.mozilla.org/en-US/docs/Web/API/OffscreenCanvasRenderingContext2D#text_styles

Created #235316 to track

[AndreiKrutikov]

It works strangely on the latest Insiders build. Some of the ligatures are working, and some are not. Cannot figure out the rule, but for instance '=>' works, but not '-<'.
Note that it doesn't work in the input but does work on the output; some ligatures don't work either on the input line or in the output.

[Master-Hash]

It works strangely on the latest Insiders build. Some of the ligatures are working, and some are not. Cannot figure out the rule, but for instance '=>' works, but not '-<'.
Note that it doesn't work in the input but does work on the output; some ligatures don't work either on the input line or in the output.

I found - and < has different colors in the first line, which may be the reason.

The third line is correct.

[Tyriar]

I found - and < has different colors in the first line, which may be the reason.

@Master-Hash yes that's by design in that particular case since pwsh is coloring is differently

[sunshaoce]

I encountered a problem where the progress bar cannot be displayed correctly in the terminal using the Fira Code font.

echo "[=========================---------------------------------------------------------------]"

Will be

[Tyriar]

@sunshaoce tracked in #235988 👍