Bug 227224
| Summary: | Text disappears for multiple seconds when font requested but load interrupted | ||
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| Product: | WebKit | Reporter: | ian |
| Component: | Text | Assignee: | Nobody <webkit-unassigned> |
| Status: | NEW | ||
| Severity: | Trivial | CC: | mmaxfield, webkit-bug-importer |
| Priority: | P2 | Keywords: | InRadar |
| Version: | Safari 14 | ||
| Hardware: | All | ||
| OS: | All | ||
| See Also: | https://bugs.webkit.org/show_bug.cgi?id=227143 | ||
ian
In Safari/Mobile Safari 14 text stops rendering for a several seconds in an peculiar circumstance:
• Nothing on the page initially needed a font specified in @font-face.
• A style was changed such that that font is now needed, triggering the lazy load.
• The font-face in question has font-display:auto.
• The font download is ~interrupted~ after it's requested.
In Chrome, Firefox, and earlier versions of Safari there is an observable but brief 'blink' (maybe ~250ms), but in Safari 14 the disappearance can be several seconds long
Reproduction is here: http://ianbellomy.com/test/font-failure-test.html
(Note that caching may eliminate the issue if the page is refreshed.)
Admittedly the situation is pretty peculiar but it also seems like 'auto' should not lead to a behavior like this.
FWIW, I ran into this after having done something bone-headed but it seems possible to inadvertently hit this in a large project, if, through some project change, a font is no longer needed on initial presentation, and additional network traffic is needed to properly display the site. In a PWA type situation for example a user might install the PWA but not hit an area that needs a font until they go to use the PWA while offline. I haven't tested for a 'failed' response though (opposed to an interruption).
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Radar WebKit Bug Importer
<rdar://problem/79871859>