- From: Richard Schwerdtfeger <schwer@us.ibm.com>
- Date: Thu, 11 Mar 2010 09:43:22 -0600
- To: Maciej Stachowiak <mjs@apple.com>
- Cc: Steven Faulkner <faulkner.steve@gmail.com>, public-canvas-api@w3.org, HTMLWG WG <public-html@w3.org>, HTML Accessibility Task Force <public-html-a11y@w3.org>, public-html-a11y-request@w3.org
- Message-ID: <OF1AF29C5D.27DEB5A3-ON862576E3.0053F3A3-862576E3.00565E26@us.ibm.com>
Hi Maciej, First, this is great feedback. I tried to stay in line with what was in the 2D Context draft that was out there, which in the fine print, indicated that the focus rectangle was also used for caret. It was unclear how much of the drawFocusRing() was implemented and I tried not to break things. So, I also had problems with reusing the same method. Here is the the text in the existing text that I am referring to: "The position of the center of the control, or of the editing caret if the control has one, should be given in the x and y arguments." So, it appears you are in agreement with simply having caret API that says setCaretPosition with a set of coordinates. As it states it would be bound to an element in the subdom which has a logical character position which the author would synch with. This we have in the proposal. I will simply separate them out. Second, if we require the author to do all the caret drawing I see a problem with not honoring blink rate settings that the author does not have access to. If the blink rate is high enough (greater than 3 times a second) this may call seizures in some users. Should we not provide the ability for the user agent to override the drawing in some way? Third, what I and others are struggling with is canDrawCustom on drawFocusRing(): "If the canDrawCustom argument is true, then the focus ring is only drawn if the user has configured his system to draw focus rings in a particular manner. (For example, high contrast focus rings.)" This does not make sense. The parameter, my name, indicates that the author can draw a custom focus rectangle. It would make more sense to say that the focus ring is drawn, by the user agent, only if the user has configured the system to draw focus rings in a particular matter. ... meaning the user has configured the desktop to draw focus rings in a standard way and the author should not override that. Do you agree? Rich Rich Schwerdtfeger CTO Accessibility Software Group Maciej Stachowiak <mjs@apple.com> Sent by: To public-html-a11y- Steven Faulkner request@w3.org <faulkner.steve@gmail.com> cc HTML Accessibility Task Force 03/08/2010 03:01 <public-html-a11y@w3.org>, PM public-canvas-api@w3.org, HTMLWG WG <public-html@w3.org>, Richard Schwerdtfeger/Austin/IBM@IBMUS Subject Re: change proposal: Provide accessibility implementation information (in the Canvas 2d Context specification) for focus rectangle and caret On Mar 4, 2010, at 4:41 AM, Steven Faulkner wrote: > change proposal based on changes (written by Rich S) to the canvas 2d > context spec > http://www.w3.org/html/wg/wiki/ChangeProposals/canvasaccessibility > > resolves bug 8722 (http://www.w3.org/Bugs/Public/show_bug.cgi?id=8722) > <chair hat off> It seems odd to me that this proposal overloads drawFocusRing to also handle tracking the caret in a canvas: 1) The caret is a kind of selection, not a kind of focus ring. Rather than overloading drawFocusRing, there should be a way to indicate a selection region, possibly collapsed to a caret. 2) On many operating systems the caret blinks in the default system appearance, so using a single call to draw it once will not do. At best you can report its position and it has to be up to the specific Web application to manage drawing it. 3) It seems to me that if the <canvas> has a navigable/accessible subdom, then it can semantically indicate focus and selection by placing the DOM selection somewhere in the subdom. The only piece missing is associating that with some screen coordinates. Regards, Maciej
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Received on Thursday, 11 March 2010 15:44:26 UTC