- From: Thomas Phinney <thomas.phinney@gmail.com>
- Date: Wed, 9 Feb 2011 07:11:09 -0800
- To: Chris Lilley <chris@w3.org>
- Cc: "www-font@w3.org" <www-font@w3.org>, "www-svg@w3.org" <www-svg@w3.org>
I'll just note that if one wants a system to deal with real-world fonts, it should deal with inputs for usWeightClass that are any integer from 0-1000. I am curious as to what everyone thinks a font creator should do if they have a family with three or more weights that are heavier than "bold" (which maps to 700). In our collection of about two thousand web fonts, as I recall there are four such cases. This is aside from the many other cases where values aren't in hundreds, etc. I remain puzzled that CSS 3 will remain deliberately incompatible with real fonts in this area. T On Feb 9, 2011, at 6:20, Chris Lilley <chris@w3.org> wrote: > Hello www-font, > > Open Font Format (OFF [1]) states that OS2.usWeightClass is a 2-byte unsigned short and describes it as > > "Indicates the visual weight (degree of blackness or thickness of strokes) of the characters in the > font." > > There is an accompanying table which relates particular values 9100, 200 etc) to textual descriptions (e.g. 'Thin') and C definitions from windows.h (e.g. FW_THIN). > > Values which are not multiples of 100 are not specifically allowed and not specifically disallowed; they just don't have a defined mapping to those two string sources. > > I have seen fonts with weights like 250 etc so I conclude that in OFF, OS2.usWeightClass is a continuous range of cardinal numbers. > > CSS3 Fonts states that the font-weight property [2], used to request styling, is an ordered sequence of tokens: > > "100 to 900 > These values form an ordered sequence, where each number indicates a weight that is at least as dark as its predecessor." > > and > > "Font formats that use a scale other than a nine step scale should map their scale onto the CSS scale" > > and that the font-weight descriptor [3], used to tell CSS about the weight of a particular font, is also a discrete series of tokens: > > "Value: normal | bold | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900" > > so I conclude that values like 250 are explicitly disallowed. > > The point of this email is to ask: > > a) are the above assumptions correct? > b) if a value which is not a multiple of 100 is used in the CSS style system, (e.g by script, or by direct specification in a style sheet, or by animation) then it gets mapped to the nearest multiple of 100? > c) thus, animation of the font-weight property should be discrete, not continuous, despite the fact that fonts with wights that are not a multiple of 100 may be available, as the CSS style shystem does not expose their native weights? > > Tracker, this relates to SVG-ACTION-2936 > > > [1] ISO 14496-11:2009(E) > PDF downloadable at no charge by agreeing to > http://standards.iso.org/ittf/licence.html > > [2] http://dev.w3.org/csswg/css3-fonts/#font-weight-prop > > [3] http://dev.w3.org/csswg/css3-fonts/#font-prop-desc > > > -- > Chris Lilley Technical Director, Interaction Domain > W3C Graphics Activity Lead, Fonts Activity Lead > Co-Chair, W3C Hypertext CG > Member, CSS, WebFonts, SVG Working Groups > >
Received on Wednesday, 9 February 2011 15:13:01 UTC