"Pixels per inch (PPI)"
That's what I like about standards. The rest of the world uses the Metric system, yet we are stuck with these archaic units because the U.S. refuses to get with the program. How's that for a 'moral high horse'? ;) cheers, Geoff. > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of liorean > Sent: Thursday, 2 February 2006 8:35 AM > To: wsg@webstandardsgroup.org > Subject: Re: [WSG] Which unit is better for web site font size? > > > On 01/02/06, Brian Cummiskey <[EMAIL PROTECTED]> wrote: > > Minh D. Tran wrote: > > > My personal preference has always been pt. I've looked at many > > > professional source codes and alot of them uses px or % > to measure size > > > of items (divs, img, etc), em for positioning, and pt for > font sizes. > > pt is for PRINT media, not screen. > > Wrong. Points are for all devices that operate at different ppi* than > 96. Points have a locked points per logical inch resolution of 72. > Pixels vary depending on ppi. So, if a medium has 96 ppi then a 12pt > text will be rendered as 12*96/72=16px. If a medium has 120 ppi, then > the same 12pt text will be rendered as 12*120/72=20px. If a device has > 300 ppi, the 12pt text will be rendered as 12*300/72=50px. And the > reverse is also true. That means that 16px text on a 96 ppi medium > will be rendered the same size as 16*72/96=12pt. If a medium has 120 > ppi, 16px text will be rendered as 16*72/120=9.6pt, and if a medium > has 300 ppi the 16px text will be rendered as 16*72/300=3.84pt. > ...except for the fact that the CSS reference pixel is defined at > about 1/96 inch and not the actual medium pixels, so a smart renderer > that knows about it's medium's ppi might scale it and thus make sure > that 16px=12pt is always true. That knowledge or it's implementation > for that matter is not guaranteed, however. > > * Pixels per "logical" inch, which is about equivalent to dots per > physical inch as is used in print media. Default in Windows is 96 > (Windows even calls it DPI), or 120 for large size. > -- > David "liorean" Andersson > <uri:http://liorean.web-graphics.com/> ****************************************************** The discussion list for http://webstandardsgroup.org/ See http://webstandardsgroup.org/mail/guidelines.cfm for some hints on posting to the list & getting help ******************************************************
