Comment by perching_aix
Comment by perching_aix 19 hours ago
> Number of monospaced font character blocks this string will take up on the screen
To predict the pixel width of a given text, right?
One thing I ran into is that despite certain fonts being monospace, characters from different Unicode blocks would have unexpected lengths. Like I'd have expected half-width CJK letters to render to the same pixel dimensions as Latin letters do, but they don't. It's ever so slightly off. Same with full-width CJK letters vs two Latin letters.
I'm not sure if this is due to some font fallback. I'd have expected e.g. VS Code to be able to be able to render Japanese and English monospace in an aligned way without any fallbacks. Maybe once I have energy again to waste on this I'll look into it deeper.
(Some but not all) terminal emulators are capable of rendering CJK perfectly aligned with Latin even when mixing fonts. Browsers are fundamentally incapable of that because aligning characters in different fonts wasn’t a goal at all. VS Code being a webview under the hood means it inherited this fundamental incapability.* Therefore, don’t hold your breath.
* I'm talking about the DOM route, not <canvas> obviously. VS Code is powere by Monaco, which is DOM-based, not canvas-based. You can "Developer: Toggle Developer Tools" to see the DOM structure under the hood.
** I should further qualify my statement as browsers are fundamentally incapable of this if you use native text node rendering. I have built a perfectly monospace mixed CJK and Latin interface myself by wrapping each full width character in a separate span. Not exactly a performance-oriented solution. Also IIRC Safari doesn’t handle lengths in fractional pixels very well.