- From: Steven Faulkner <faulkner.steve@gmail.com>
- Date: Thu, 15 Jul 2010 11:06:07 +0100
- To: Richard Schwerdtfeger <schwer@us.ibm.com>
- Cc: HTML Accessibility Task Force <public-html-a11y@w3.org>, Janina Sajka <janina@rednote.net>
- Message-ID: <AANLkTilSI-0sYN2hag-RsuzYi4vk5Z3QPRE93q9cjimD@mail.gmail.com>
Hi Rich, james graham wrote: > I had a short discussion on IRC with Hixie and Maciej about this API here is some feedback on the current chnage proposal from Ian: via IRC ( http://krijnhoetmer.nl/irc-logs/whatwg/20100715#l-430) <Hixie> gotta love http://www.w3.org/html/wg/wiki/ChangeProposals/canvasaccessibility # <http://krijnhoetmer.nl/irc-logs/whatwg/20100715#l-432> [08:44] <Hixie> "Currently the spec does not include requirements for implementers on how to provide accessible focus rectangles [...] The details of the proposal are [...] A change to drawFocusRing()" # <http://krijnhoetmer.nl/irc-logs/whatwg/20100715#l-434> [08:46] <Hixie> my god this proposal is messed up # <http://krijnhoetmer.nl/irc-logs/whatwg/20100715#l-435> [08:47] <Hixie> it has authoring conformance criteria literally in the middle of a UA algorithm # <http://krijnhoetmer.nl/irc-logs/whatwg/20100715#l-436> [08:47] <Hixie> it uses the wrong coordinate system # <http://krijnhoetmer.nl/irc-logs/whatwg/20100715#l-437> [08:47] <Hixie> it's self-contradictory in fact about the coordinate system it uses # <http://krijnhoetmer.nl/irc-logs/whatwg/20100715#l-438> [08:48] <Hixie> it has an entirely useless set of arguments for the focus ring <Hixie> seriously, read this: # <http://krijnhoetmer.nl/irc-logs/whatwg/20100715#l-448> [08:50] <Hixie> http://lists.w3.org/Archives/Public/public-canvas-api/2010AprJun/att-0054/2dcontext10-June-7.html#dom-context-2d-setCaretSelectionRect # <http://krijnhoetmer.nl/irc-logs/whatwg/20100715#l-449> [08:51] <Hixie> the definition of setCaretSelectionRect # <http://krijnhoetmer.nl/irc-logs/whatwg/20100715#l-450> [08:51] <Hixie> read that algorithm # <http://krijnhoetmer.nl/irc-logs/whatwg/20100715#l-451> [08:51] <Hixie> it has authoring criteria, it has asynchronous requirements, and then it ends with "return true" # <http://krijnhoetmer.nl/irc-logs/whatwg/20100715#l-453> [08:52] <Hixie> and that's ignoring the main problem of course, which is that the entire method is completely useless # <http://krijnhoetmer.nl/irc-logs/whatwg/20100715#l-454> [08:52] <Hixie> it does nothing if you don't have an AT, so nobody will ever use it # <http://krijnhoetmer.nl/irc-logs/whatwg/20100715#l-455> [08:52] <Hixie> plus it doesn't even do anything useful if you DO have an AT, since who on earth has a selection area that is just a rectangle with no associated selected text? regards Stevef On 15 July 2010 10:40, James Graham <jgraham@opera.com> wrote: > On 06/16/2010 03:06 PM, Richard Schwerdtfeger wrote: > > Sorry for taking so long to respond to this, it got lost somewhere in my > pile of things to do. > > > James Graham <jgraham@opera.com> wrote on 06/15/2010 04:37:06 AM: >> >> > From: James Graham <jgraham@opera.com> >> > To: Janina Sajka <janina@rednote.net>, HTML WG <public-html@w3.org>, >> > Steven Faulkner <faulkner.steve@gmail.com>, Richard Schwerdtfeger/ >> > Austin/IBM@IBMUS, public-html-a11y@w3.org >> > Date: 06/15/2010 04:37 AM >> > Subject: Re: HTML-A11Y Task Force Recommendation: ISSUE-74 Canvas- >> > Accessibility >> > >> > On 06/14/2010 10:16 PM, Janina Sajka wrote: >> > >> > > http://www.w3.org/html/wg/wiki/ChangeProposals/canvasaccessibility >> > >> > Some thoughts on these changes: >> > >> > > A frustrating point for working group members is that this proposal has >> been out for month and it was not until after an entire vote for >> consensus was reached that we get a comment from Opera. In the future it >> would be appreciated >> if we could receive comments earlier. >> > > (I should note that my comments are not "from Opera" in any sense more than > the minimum implied by the fact that I wrote them and I am employed by > Opera. In particular, others at Opera might disagree with me.) > > > > == drawFocusRing(element, x,y,w,h,[drawCustomRing]) == >> > >> > The algorithm for determining the rectangle fails to take account of >> the >> > current transformation matrix. This seems bad because it means that >> > under general transformations, the focus region will be the wrong size. >> > >> > In general if the current path is known, it seems that it is possible >> > for the UA to calculate the best-fitting size of the bounding >> rectangle. >> > Therefore it is unclear why the author is expected to recompute this >> > size explicitly. >> > >> To be clear, are you suggesting that the author need only pass the x, y >> coordinates which would be relative to the canvas area? >> The rectangle would then be computed by the user agent based on the >> drawing path from that point. >> > > Yes. > > > If so, I don't have an issue with this. We added the w, and h parameters >> in response to feedback from others. >> > > I would be interested in hearing the use cases they presented. If there are > cases that require something unusual, the parameters should be optional. > > > > It is unclear why the focus ring is restricted to a rectangle in the >> > UA-drawn case when it is allowed to follow an arbitary path in the >> > original spec. >> > >> Accessibility API services currently use rectangles to represent the >> visual focus rectangle. We are not restricting what the author draws. This >> is why we are suggesting a rectangle best fit. >> > > OK, I think the proposal implies that the UA may only draw a rectangle. The > wording should be changed here. > > > > It is unclear to me what it means to "draw the focus ring based on the >> > final role computed from the native host language semantics and the >> > supplied role attribute" >> > >> This simply states that in the case where the user agent is drawing the >> focus rectangle based on operating system conventions then those >> conventions >> may require that a focus ring is drawn in a certain way based on the >> role. For example, the focus ring for a checkbox may be different from >> an item in a tree widget. Who knows, the platform may require that a >> checkbox be drawn like an ellipse or with a specific color scheme. This >> simply >> provides for that. >> > > OK. It could be clearer in the change proposal. > > > > == setCaretSelectionRect(element, x, y, w, h) == >> > >> > I found the introductory text quite hard to follow here. In addition, >> > there are several typos. As an author I think I would have considerable >> > difficulty figuring out what I was supposed to use this method for even >> > if I thought I needed it. >> > >> > It is not clear why this method only works when an element is focused. >> > Although the caret is tied to focus, the selection can presumably >> > adjusted without focusing the selected element (e.g. a select text >> > button in the application UI). >> > >> If the element is not focused or a descendant of what is focused the >> user is not directly operating with >> that UI element. They are operating another UI element and the magnifier >> needs to track >> the component the user is operating. It does not help the low vision >> user if they cannot >> see the component they are operating which would be the one with focus. >> > > It was totally unclear to me that this was supposed to be entirely about > the caret and not the selection. If the use case is "magnifier needs to know > where to centre", why do you need the width and height arguments? > > I had a short discussion on IRC with Hixie and Maciej about this API and it > was suggested that the use cases might be better addressed with a drawCaret > API. Like drawFocusRing it would have a use in the non-accessibility case, > which would mean that it was much more likely to be used correctly by > typical authors. With sufficient cleverness it could handle blinking, and > the blink rate could be taken from the OS settings, thus eliminating the > need for the caretBlinkRate() API. I think this design is sufficiently more > promising than the existing proposals that we should wait for it to be > fully fleshed out before making any decisions here. I believe Hixie is > prepared to spec out a drawCaret API but I don't know what his timetable is. > -- with regards Steve Faulkner Technical Director - TPG Europe Director - Web Accessibility Tools Consortium www.paciellogroup.com | www.wat-c.org Web Accessibility Toolbar - http://www.paciellogroup.com/resources/wat-ie-about.html
Received on Thursday, 15 July 2010 10:07:03 UTC