- From: Tim Boland <frederick.boland@nist.gov>
- Date: Thu, 05 May 2005 11:46:06 -0400
- To: "John M Slatin" <john_slatin@austin.utexas.edu>
- Cc: w3c-wai-gl@w3.org
By "visual display order" and "CSS positioning" (in excerpted text following), are you specifically referencing implementations of the CSS2.1 visual rendering model, in which each element in the document tree generates zero or more rectangular boxes in the rendering structure, as well as the visual rendering model aspects, the box model (describing the generation of such boxes, controlled by the "display" property), and the visual flow model, describing how each box receives its final position, based upon relationships of source elements in the document tree, box dimensions, and canvas dimensions (and including the "position" and "float properties)? I think that the "interaction" of values of "display", "position", and "float" properties (as well as applicable values of "top", "right", "bottom", "left", "direction", "clear", and "z-index" properties) may have accessibility implications pertaining to the discussion excerpted following.. >my lifetime. But the replacement-- CSS positioning-- raises the same >possible problems because it *does* (or can) separate content and >structure from presentaition (even if the boundary gets blurred >sometimes). Mostly that's a good thing for accessibility-- it means >that the visual display order and the auditory sequence can be different >and each be "tuned" to the needs of a different segment of the audience. >But the decoupling can be problematic if the order of the content in the >delivery unit doesn't work as a linear sequence-- even if the order in >the source follows the visual order.
Received on Thursday, 5 May 2005 15:46:37 UTC