- From: Kasday, Leonard <kasday@att.com>
- Date: Tue, 3 Feb 1998 09:52:17 -0500
- To: w3c-wai-ig@w3.org
Leigh, re your question > Does anyone have any thoughts on ways around the web access difficulties > which arise when using a touch screen (without a physical keyboard). LRK:: This is interesting from a disability standpoint because - an able-bodied (or temporarily able bodied, TAB) person using a touch screen encounters functional limitations similar to those of a person with a motor impairment using a device such as a mouse or trackball. - the methods needed to help a TAB person handle closely spaced links with a touch screen may help people with motor impairments handle the more widely spaced links on that touch screen. - some of the approaches (#3, 4 below) only work well if the page was designed to be accessible for people with who have low vision and/or are blind. - the on-screen keyboard needed for alpha input is like those used in some disability apps. In short, a case for universal design. And now for some suggestions.... Aside from Alpha input, the main problem for using a touch screen on a web page is difficulty of hitting the target accurately. There are a number of ways around this: 1. If you have a force sensitive touch screen, then you can position a pointer by lightly moving your finger until the pointer lines up with the target and then pressing harder. However, I don't know of any commercially available force sensitive touch screens. (I designed a couple of such screens a while back but they are not currently manufactured: cf. patent 4,710,760 Photoelastic touch-sensitive screen patent 4,484,179 Touch position sensitive surface Hmmm. I wonder how these would work for a person with motor impairments? Maybe use to smooth tremors? Well, that's off the point at the moment) 2. There's also the "drag tap" interface like what's used in some laptops with touch pads. You drag the pointer to the screen by sliding your finger to the spot and then tap (anywhere) to activate. So you can get more accuracy than if just touching the screen activated the link. If this is for casual walk-up use though, some people might not catch on. Also, this could cause problems for person with motor impairments. 3. Getting to your question about doctoring the pages, you could decrease the need for fine positioning by enlarging all the text links by increasing the font size, and magnfiy all image maps till targets are separated. This would screw up layout of some web pages unless... and this is interesting... the author of the web page designed it with ACCESSIBILITY in mind to allow it to take larger font sizes. E.g. by avoiding a backbround image that's supposed to line up with text, e.g. the left hand menu bar idiom. 4. Another way to doctor the page would add javascript whereever there are closely spaced links so that clicking on one of the lines brings up a menu of the nearby links. Again, this works best if the page was designed to be accessible: with links that make sense when read alone out of context (to avoid a menu that says click here click here click here And ALT text for each AREA in an image map. ------------------------------------------------------------------------ ------- There's also the issues of making sure tha people with disabilities can use these screens, especially if you're looking a kiosks. For people who are blind, you'll need a speech interface, e.g. Gregg Vanderheiden's speech system. Plus, it should be possible to contol the link spacing criterion so that people with motor impairments can get assistance. In general, some work would be needed to help people with motor impairments use the screen. E.g. anti bounce, motion averaging. Also, you'll need an onscrren keyboard for alpha input. Len All opinions expressed here are my own, not necessarily those of my employer. ============================================================= kasday@att.com phone 732 949 2693 Leonard R. Kasday Room 1J-316A AT&T Laboratories 101 Crawfords Corner Rd. Holmdel NJ 07733
Received on Tuesday, 3 February 1998 09:52:21 UTC