On 2007/03/27 08:18 (GMT+0300) Jukka K. Korpela apparently typed: > On Mon, 26 Mar 2007, Felix Miata wrote:
>> To be clear, all IE versions default not to Xpx, but to 12pt. The M$ factory >> default DPI is 96, which translates 12pt to 16px. > I think it needs to be added that this correspondence (or some other > correspondence that has been chosen) does not change when the monitor > resolution is changed. Thus, if a user chooses a different resolution > among the available options, 12pt will still be 16px. This means that "pt" > will not match its definition any more; it will be different from the > typographic point. Similarly, "mm" will be different from the physical > millimeter and "in" different from the inch. > The point (no pun intended) is that the "physical" units aren't really > physical in all circumstances. Setting (or defaulting) something to 12pt > may make it physically 12 typographic points in most circumstances, but > not all. I was remiss in my previous reply leaving out this important point about the error characteristic of pt and the other CSS "physicial" units. Traditionally on M$ systems at least the relationship between these purported physical units and real physical measurements has been awful. Back when 640x480 was normal and 13" nominal/12" actual displays were also typical, the 96 DPI assumption made 12pt, and thus 16px, produce a 12pt font that was approximately 17.3pt in physical size. The "better" systems of those days running 800x600 on 14" nominal/13" actual displays did slightly better at about 15.0pt. As things evolved to 1024x768 on 17" nominal/16" actual a further small improvement was made to about 14.4pt. The previous paragraph describes the apparent basis for a couple of web developer traditions: 1-the defaults are too big 2-physical units like pt should not be used for sizing text via CSS I believe the second item above remains a good recommendation, but with the continued increase in display sizes and resolution, the first has evolved into a bad assumption. On a current entry level 15" 1024x768 flat panel display the actual size of 12pt/16px has dropped to 13.5pt. At one step up to 1280x1024 on 17", the error is down to 0.1pt at 11.9pt actual for 12pt/16px. For widescreen laptops, which have been outselling desktops for some time now, the error shift is more pronounced. At entry level WXGA (1280x800) 15.4" 12pt/16px is 11.8pt. Some upgrades are 11.5pt on WXGA+ (1440x900) 17", 9.9pt on WSXGA+ (1680x1050) 18", and 9.7pt on WUXGA (1920x1200) 19". These examples and other combinations can be found on http://mrmazda.no-ip.com/auth/Font/fonts-pt2px-tabled.html. This error shift to negative has resulted in laptop manufacturers setting the system DPI instead of the M$ 96 nominal default to 120. This generally keeps the IE 12pt default reasonably close to 12pt actual, but is of no help to Gecko browser users (whose defaults are OEM specified in px) or when CSS has specified font sizes in px. The "16px default" on average is considerably smaller than it used to be, and, on average, probably anything but "too big" any more for normal people. http://mrmazda.no-ip.com/auth/bigdefaults.html -- "For God did not send his Son into the world to condemn the world, but to save the world through him." John 3:17 NIV Team OS/2 ** Reg. Linux User #211409 Felix Miata *** http://mrmazda.no-ip.com/ ______________________________________________________________________ css-discuss [EMAIL PROTECTED] http://www.css-discuss.org/mailman/listinfo/css-d IE7 information -- http://css-discuss.incutio.com/?page=IE7 List wiki/FAQ -- http://css-discuss.incutio.com/ Supported by evolt.org -- http://www.evolt.org/help_support_evolt/
