- From: Laura Carlson <laura.lee.carlson@gmail.com>
- Date: Wed, 12 Jul 2017 07:25:59 -0500
- To: John Foliot <john.foliot@deque.com>, Greg Lowney <gcl-0039@access-research.org>, Jason White <jjwhite@ets.org>, Detlev Fischer <detlev.fischer@testkreis.de>
- Cc: "w3c-wai-gl@w3.org" <w3c-wai-gl@w3.org>, public-low-vision-a11y-tf <public-low-vision-a11y-tf@w3.org>
Hello John, Greg, Detlev, Jason, and everyone, Based on Wayne's research and analysis, I previously suggest the following for the Adapting text SC. * line spacing (leading) to at least 1.5 (space-and-a-half) * spacing between paragraphs to at least 2 (two spaces) larger than the line spacing * letter spacing (tracking) to at least 0.12 em * word spacing to at least 0.16 em On the call yesterday [1], some folks brought up that they felt the use of "spaces" to measure leading for the Adapting Text SC is untestable. At one point line-height was suggested. Detlev, you were absolutely correct when you said, "if memory serves line-height needs no unit". In CSS line-height is unitless. Eric Meyer explained that in "Unitless line-heights". [2] It inherits from the font size. This was discussed on in the Adapting text GitHub Issue last March [3]. Moreover, WCAG 2.0 1.4.8 Visual Presentation [4] uses the "spaces" and "paragraphs" for units. It states: "...Line spacing (leading) is at least space-and-a-half within paragraphs, and paragraph spacing is at least 1.5 times larger than the line spacing..." Is that currently untestable? If not, why not re-purpose that terminology? As for using ems as a unit perhaps we need a definition because that is a new concept for WCAG. How about something like: em: A length unit relative to the font-size that is used. e.g., letter spacing of 0.12 em means 0.12 spacing in addition to the default space between letters of the font size in use. Ideas for improvement? Other thoughts? Thanks everyone. Kindest regards, Laura [1] https://www.w3.org/2017/07/11-ag-minutes.html#item02 [2] http://meyerweb.com/eric/thoughts/2006/02/08/unitless-line-heights/ [3] https://github.com/w3c/wcag21/issues/78#issuecomment-288755938 [4] http://www.w3.org/TR/WCAG20#visual-audio-contrast-visual-presentation -- Laura L. Carlson
Received on Wednesday, 12 July 2017 12:26:34 UTC