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Re[2]: pixels to ems - was RE: Relative vs. absolute units


From: Jared Smith
Date: Jan 7, 2003 6:42PM


KB> An em only equals 16 pixels as long as the font size equals 16 pixels.

Which, by default, it roughly does on most systems. The power of ems
is that the size is contingent upon the users settings, yet still
maintains the relative sizing that the developer wants. For the
majority of users who have not changed their default font or user
style sheet, then 16 pixels = 1em is a good guideline to base your text
sizing, though this changes slightly based on OS, browser, font
settings, or weather patterns (ok, it only seems that way).

The danger comes in a design that is not useable when 1em does not
equal the same font size that the majority of us use. What happens to
your page when 1em = 48 pixels? Good design that allows scaling and
utilizes relative size values almost always provides excellent
implementation of ems.

A great, though somewhat antiquated, overview of relative and absolute
sizing and the limitations thereof can be found at

Jared Smith
WebAIM (Web Accessibility In Mind)
Center for Persons with Disabilities
Utah State University

On Tuesday, January 07, 2003 you sent:
KB> An em equals the size of the current font, and that can be changed by
KB> the browser,
KB> by the user, by the author's style sheet, by the user's style sheet, by
KB> the HTML,
KB> ...

KB> An em only equals 16 pixels as long as the font size equals 16 pixels.

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