Yeah, I never would have disagreed with that. Which is why I said “Both seem like pretty weak excuses to me.”
By “non-negligible” I meant something like 2–10 times slower (you’d have to test to be sure... I tried searching around but couldn’t find any direct speed comparisons). For typical pages it’s not going to matter, but if you have a page like the HTML5 spec, where it takes a half a second to resize a window now, it’s going to be noticeably slower using a more sophisticated paragraph composer.
Keep in mind, Safari doesn’t even do kerning, because they’re afraid it’d be too slow. (Also a ludicrous excuse for desktop hardware and typical web pages, IMO.)
And the Safari guys also use the same excuse (“it’s too slow”) for not doing real color management with CSS/HTML colors.
Before we make fun of the webkit folks for not doing the proper work because "it's too slow," remember that these are the same folks that we praise for making the fastest dang HTML rendering engine on the planet. (Or near enough.) Their culture of performance has significantly raised the standard of web browsing performance, and that's not something to take lightly.
I imagine it would have to make a fairly significant difference in rendering quality in order to make any speed losses worthwhile. Death by a thousand cuts and all that.
I would like to have two browsers of the same type, one with high(er) quality typography and one as it is now. And then compare the speed. That would be interesting.
By “non-negligible” I meant something like 2–10 times slower (you’d have to test to be sure... I tried searching around but couldn’t find any direct speed comparisons). For typical pages it’s not going to matter, but if you have a page like the HTML5 spec, where it takes a half a second to resize a window now, it’s going to be noticeably slower using a more sophisticated paragraph composer.
Keep in mind, Safari doesn’t even do kerning, because they’re afraid it’d be too slow. (Also a ludicrous excuse for desktop hardware and typical web pages, IMO.)
And the Safari guys also use the same excuse (“it’s too slow”) for not doing real color management with CSS/HTML colors.