- From: Richard Schwerdtfeger <schwer@us.ibm.com>
- Date: Mon, 31 Oct 2011 18:32:11 -0500
- To: Jonas Sicking <jonas@sicking.cc>, public-canvas-api@w3.org, public-html-a11y@w3.org
- Cc: chucko@jumis.com, cyns@exchange.microsoft.com, david.bolter@gmail.com, franko@microsoft.com, janina@rednote.net, jbrewer@w3.org
- Message-ID: <OF5DA20EC1.B91695C7-ON8625793A.008121CC-8625793A.00814A0A@us.ibm.com>
Jonas, We discussed your points on the PF call today. Apple was present. I will write up a revised draft that associated drawing to the elements per your request. Thanks for you feedback. Rich Rich Schwerdtfeger CTO Accessibility Software Group From: Richard Schwerdtfeger/Austin/IBM@IBMUS To: Jonas Sicking <jonas@sicking.cc>, Cc: chucko@jumis.com, cyns@exchange.microsoft.com, david.bolter@gmail.com, franko@microsoft.com, janina@rednote.net, jbrewer@w3.org, public-canvas-api@w3.org, public-html-a11y@w3.org Date: 10/31/2011 11:03 AM Subject: Re: draft of hit testing on active regions (actually paths) in canvas Rich Schwerdtfeger CTO Accessibility Software Group Jonas Sicking <jonas@sicking.cc> wrote on 10/27/2011 07:42:40 PM: > From: Jonas Sicking <jonas@sicking.cc> > To: Richard Schwerdtfeger/Austin/IBM@IBMUS, > Cc: franko@microsoft.com, chucko@jumis.com, david.bolter@gmail.com, > cyns@exchange.microsoft.com, public-html-a11y@w3.org, > janina@rednote.net, jbrewer@w3.org, public-canvas-api@w3.org > Date: 10/27/2011 07:43 PM > Subject: Re: draft of hit testing on active regions (actually paths)in canvas > > Some feedback: > > Limiting to only allowing paths seems like a unfortunate limitation. > For example it misses calls to drawImage which I think is quite > common. I'd rather prefer a call where you say "all drawing operations > from this point should be considered drawing for element X", then let > the page do arbitrary drawing operations, then have a second call > which says "i'm now drawing for element Y" or "I'm now drawing for no > element". > I see. So what would you use compute the bounds? Do you use the all the points to compute a single rectangle for hit testing? ... or do you compute multiple paths for an element to do hit testing on? > What is the use case for the zIndex argument? The actual pixel drawing > operations hasn't had a need for that so far and instead rely on the > painters algorithm. It seems better to me to have a direct mapping > between the drawing operations and the accessibility API. > zIndex: Performance and authors may have overlapping drawing objects. > Why return false rather than throw an exception if the element doesn't > exist? Also what do you mean by "doesn't exist". If the element > doesn't exist then how could the page have a reference to it and pass > that reference to the function? Do you mean "element isn't inside the > canvas"? > Throwing an exception makes sense. I meant the element did not exist. I am thinking that the author may have content outside fallback such as a drop down menu. We could limit the elements to the fallback content. I would like your feedback on that. > In general I think I prefer the API I proposed in [1]. Can you > describe what problems you were trying to solve with your changes > compared to that proposal? > > [1] http://lists.w3.org/Archives/Public/public-canvas-api/2011JulSep/0195.html > > / Jonas > > On Thu, Oct 27, 2011 at 4:56 PM, Richard Schwerdtfeger > <schwer@us.ibm.com> wrote: > > Hi Frank, > > > > Thank you for the call today. I am glad we are on the same page onthe three > > basic methods for hit testing. I took the basic methods that Jonas had put > > out earlier on the list and the discussion we had in San Diego and put > > together an active regions and hit testing section. I also agree with you > > this is for when we have multiple interactive elements within canvas. I was > > glad to see that customers are starting to come to Microsoft to talk about > > building more interactive widgets with canvas - not because I want them to > > but more because it shows we are making the right moves to address canvas > > accessibility. > > > > Jonas, Charles, Frank, David, Cynthia > > > > This is a first draft and the section I would like you to look at is section > > 16. We can change the names to whatever we want. I have not yet added spec. > > information as to how existing functions like scrollElementIntoView should > > work on these elements as they should be included in the layout engine > > positioning per Jonas earlier feedback. I have also not stated how we would > > convert the paths to rectangles for the underlying OS platform accessibility > > APIs. We could either do this in the canvas spec. or in the accessibility > > API mapping guide that Cynthia is leading. We just need to decide. > > Personally, I prefer the one stop shopping. > > > > I am sure Ian will want to tweak or rewrite the algorithm section processing > > as he has his own consistent way of doing that but I took my best shot at > > it. > > > > Please review section 16. > > > > (See attached file: clickableregion.html) > > > > Since, like many of you I am going to TPAC, I will not have time to make > > changes prior to the face to face. Janina please put a link to this document > > in your canvas agenda for TPAC. > > > > See you all in California. > > > > > > Rich Schwerdtfeger > > >
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Received on Monday, 31 October 2011 23:33:46 UTC