- From: <joeclark@joeclark.org>
- Date: Tue, 03 Apr 2001 03:38:14 +0200
- To: w3c-wai-ig@w3.org
>pixels are not relative in the sense of being relative to the other >types of font. They are relative in the sense that they are not the >same size on different machines. So they aren't very helpful for a >given user, since it is hard to change the size of a pixel. That is irrelevant. It is, however, pretty easy to change the size of type used on a Web page in compliant browsers. And anyway, the Zeldman and others have documented that the only size settings that work in the real world are none at all or pixels. <http://www.alistapart.com/stories/fear4/index.html> <http://www.littlegreenfootballs.com/weblog/weblog.php?y=1&x=archives/00000214.htm> >I think the best technique is to use percentages, or em units. The >problem with smaller and larger is that some browsers define them as >a LOT smaller - to the point of being hard to read - typical use >cases don't go that far. But there is no intrinsic reason not to mix >those with percentages / ems. Except that you will always force a fraction of the user's preferred size. 0.8 em is 80% of the type size. 80% is the same as 0.8 ex, or 80% of the user's lineheight, which is almost always assigned by the browser (and will cause illegibility in Netscape 4 if you set it manually). So if I specify 17pt type as my default, and you decide that 0.8 em is what I really meant after all, I get 17*80% or 14pt type. Did I ask for that, exactly? And if I try to fix what you did by resetting my default to 20 px, I still only get 16! I don't recall anyone giving you that kind of power-- to flat-tax my font sizes, knocking off 20% no matter what I do. And what about old browsers that misinterpret what those settings are a percentage *of*? Now, obviously, if you set the type size at 13px, that isn't what I wanted, either. But it is an absolute measure and will produce reliable results on a majority of machines. If you argue that 13px on a high-resolution screen is very small, well, so will everything else be, except maybe on Mac OS X. And we're talking about low-vision users; their screen resolution is effectively enlarged anyway. Even for nondisabled users who prefer a bigger font size, what are the odds that they're using a high-resolution monitor *and* an old browser that doesn't let them resize type? Besides, Charles has conceded that <smaller> and <larger> and the other five defined sizes don't work in the real world. Why recommend something else that doesn't? The issue of font sizes is crap all around, and nothing works reliably on all browsers and platforms, or even on popular browsers and platforms. What works least unreliably are pixels or nothing at all. At some point, we have to expect cooperation from low-vision people to upgrade to browsers that permit font resizing no matter how fonts are specified in the stylesheet. IE 5 on Macintosh; Opera; most later Explorers on Windows (with limitations); and iCab (which ignores stylesheets altogether) are already there. Apparently so is IE 6 on Windows, and Mozilla and Netscape 6 on everything save for Macintosh, where a conflict with Adobe Type Reunion or something has to be worked out. - -- Joe Clark | joeclark@joeclark.org Author, _Building Accessible Websites_ (New Riders Publishing, October 2001) <http://joeclark.org/book/> | <http://joeclark.org/access/>
Received on Monday, 2 April 2001 21:38:16 UTC