- From: DERRICK, Monique <Monique.Derrick@qed.qld.gov.au>
- Date: Wed, 9 Jan 2002 09:11:10 +1000
- To: "'Charles McCathieNevile'" <charles@w3.org>
- Cc: w3c-wai-ig@w3.org
What I want to know about this is if we use em's then that completely changes the design if the viewer uses larger sizing, how do you take this into account when designing a site. Thanks Monique Derrick -----Original Message----- From: Charles McCathieNevile [mailto:charles@w3.org] Sent: Tuesday, January 08, 2002 4:29 PM To: WAI IG Subject: Pixels vs Points as a unit for sizes I think this is part of a Frequently asked Question... Using px (pixels) as a unit of measure for font sizes isn't a great idea. It takes no account of the size the user prefers to have their text so it can be easily read. It also means your text is likely to bo very different sizes on different kinds of system, so it doesn't provide control anyway. Using pt (points, or 72nds of an inch) isn't too good either. Not only does it ignore the size that the user would like to work with, but because of strange bugs in some systems it isn't actually reliable in all browsers, and you text may come out a lot smaller than expected. There are a couple of cases where it seems reasonable to use these measures: For images that do not scale well (e.g. gif, png or jpg formats) it is not a bad idea to set sizes in terms of pixels. For a narrow decorative border or horizontal line, it doesn't make that much difference what the units are. just a thought - my personal opinion. cheers chaals Vadim Plessky recently wrote: Now I realize that during 1.5 months that I am subscribed to this list, none was asking "how using pixels instead of points affects site accessibility" I am not visually impared, but have some preblems with accessing microsoft.com site (and several other sites produced with genius "Microsoft technology") Can someone take care about me, please? :-) What I found is that even if you use 'pt' font sizes - there is no warranty that your system (Windows / PC or Macintosh) has correct dpi (dots per inch) settings. And without correct dpi settings, there is no way how browser can recalculate 'pt' (or 'cm', 'mm') to number of pixels... I have read in some book /article that both Windows/PC and Macintosh are broken in terms of reporting correct dpi settings. Has someone opposite info? [ good news: recent versions of XFree86, used on Linux, can auto-detect dpi on many video adpaters/display combination, so we finally have at least one platform working ok] -- Charles McCathieNevile http://www.w3.org/People/Charles phone: +61 409 134 136 W3C Web Accessibility Initiative http://www.w3.org/WAI fax: +1 617 258 5999 Location: 21 Mitchell street FOOTSCRAY Vic 3011, Australia (or W3C INRIA, Route des Lucioles, BP 93, 06902 Sophia Antipolis Cedex, France)
Received on Tuesday, 8 January 2002 18:11:48 UTC