Xterm.js: Default fonts are vertically offset on some Linux distributions

[Tyriar]

VS Code issue: https://github.com/Microsoft/vscode/issues/36322

Getting around this will probably involve drawing a character and checking the pixels to see where it was drawn in the cell and adjusting as necessary. From what I can see this just happens on some fonts which happen to be default on Kali and Debian.

[rhamilto]

I'm seeing this in Chrome 64 on Fedora 26 where the default monospace font is DejaVu Sans Mono, but not in Firefox 58 on the same platform using the same font.

[AndrienkoAleksandr]

+1 on Fedora 25. This bug do invisible symbol "_"

[Tyriar]

@AndrienkoAleksandr the underscore thing is probably happening due to https://github.com/xtermjs/xterm.js/issues/1138

This issue is about some fonts on Linux seems to not be drawing in the right spot.

[Tyriar]

This now affects Ubuntu 18.04 as well.

[Tyriar]

I believe this has the same root cause as other funny font problems in the DOM on Linux using Chrome 66:

Maybe there's a Chromium bug tracking this?

[Demon000]

Seems like even using Roboto Mono still doesn't fix the vertical alligment. A good example is the tmux status bar as shown in this picture.

This is on Firefox. On Chrome, the problem doesn't appear.

[Tyriar]

@Demon000 for Firefox that's this one https://github.com/xtermjs/xterm.js/issues/1055

[scycer]

Do we have any ideas for a temporary fix? Just running into this issue with Ubuntu and electron.

(update) for those with this issue i just changed the font family to find one that worked. Ubuntu mono seemed to do the job for me.

[EmpireJones]

Another workaround: changing the font size (from 14 -> 13, default font) fixed the issue for me in vscode.

[resoli]

Changing fontFamily (to Ubuntu mono, for instance) does not fix, but makes the issue less evident: try to print two vertical extended bars

printf "\xe2\x94\x82\n\xe2\x94\x82\n"

or run some command that displays them (mc) and look at the gaps in vertical lines

[zwhitchcox]

I'm havingthis problem on linux, but changing the font to 'Ubuntu mono' worked for me

[Tyriar]

This issue was closed off as it's fixed in the experimental WebGL renderer addon. It's not ready yet but I'm closing this off so I don't forget about it. See this query for current webgl addon issues https://github.com/xtermjs/xterm.js/issues?q=is%3Aissue+is%3Aopen+label%3Aarea%2Faddon%2Fwebgl