- From: Christoph Päper <christoph.paeper@crissov.de>
- Date: Thu, 19 Apr 2012 15:58:58 +0200
- To: WWW Style <www-style@w3.org>
Ryosuke Niwa:
> >
> > h6 1 xx-small 0.6rem 9.6px = 7.2pt
> > x-small 0.75rem 12px = 9pt
> > h5 2 small 0.89rem 14.2px = 10.7pt
> > h4 3 medium 1rem 16px = 12pt
> > h3 4 large 1.2rem 19.2px = 14.4pt
> > h2 5 x-large 1.5rem 24px = 18pt
> > h1 6 xx-large 2rem 32px = 24pt
> > 7 xxx-large 3rem 48px = 36pt
The exact rounding and capping behavior of implementations was not my point. I just applied the draft recommendations to the frequent base size of 16 pixels.
Anyhow.
> http://trac.webkit.org/browser/trunk/Source/WebCore/css/CSSStyleSelector.cpp?rev=113922#L4920
Other bases (Todd Fahrner)
0.60, 0.75, 0.89, 1.0, 1.2, 1.5, 2.0, 3.0
CSS Level 3
3/5, 3/4, 8/9, 1, 6/5, 3/2, 2/1, 3/1
That means Webkit matches the Level 3 draft for all user-set base sizes that are not an integer between 9 an 16 pixels. (It rounds 8/9 to 0.89, but that seems reasonable.)
1 2 3 4 5 6 7 HTML
xxs xs s _m_ l xl xxl CSS
CSS Level 3 (round to nearest integer)
5, 7, 8, 9, 11, 14, 18, 27.
6, 8, 9, 10, 12, 15, 20, 30.
7, 8, 10, 11, 13, 17, 22, 33.
7, 9, 11, 12, 14, 18, 24, 36.
8, 10, 12, 13, 16, 20, 26, 39.
8, 11, 12, 14, 17, 21, 28, 42.
9, 11, 13, 15, 18, 23, 30, 45.
10, 12, 14, 16, 19, 24, 32, 48.
Quirks mode
9; 9; 9; 9, 11, 14, 18, 28:
9; 9; 9, 10, 12, 15, 20, 31:
9; 9; 9; 11, 13, 17, 22, 34:
9; 9, 10; 12, 14, 18, 24, 37:
9; 9; 10; 13, 16, 20, 26, 40:
9; 9; 11; 14, 17, 21, 28, 42.
9, 10; 12; 15, 17; 23, 30, 45.
9; 10; 13; 16, 18; 24, 32, 48.
Strict mode
9; 9; 9; 9, 11, 14, 18, 27.
9; 9; 9, 10, 12, 15, 20, 30.
9; 9; 10, 11, 13, 17, 22, 33.
9; 9, 10; 12, 14, 18, 24, 36.
9; 10, 12, 13, 16, 20, 26, 39.
9; 10; 12, 14, 17, 21, 28, 42.
9, 10; 13, 15, 18, 23, 30, 45.
9; 10; 13; 16, 18; 24, 32, 48.
1 2 3 4 5 6 7 HTML
xxs xs s _m_ l xl xxl CSS
Assuming an implied default minimum font size of 9px, the “Strict mode” deviates from the current draft (i.e. is 1px too small) only for
— ‘small’ at base 12px,
— ‘x-small’ at bases 14px and 15px,
— ‘xx-small’, ‘x-small’ (2px difference), ‘small’ and ‘large’ at base 16px.
It’s of course more than unfortunate that the most and largest differences occur for the most common default font size.
By mere inspection, I couldn’t find a simple rounding behavior that would result in the “Strict” matrix algorithmically. I’m curious which design rationale it originates from since it differs from the “Quirks” variant significantly.
Received on Thursday, 19 April 2012 13:59:24 UTC