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Re: Draft Revisions to Canvas 2D Context API to drive magnification

From: Richard Schwerdtfeger <schwer@us.ibm.com>
Date: Mon, 31 May 2010 08:43:48 -0600
To: James Craig <jcraig@apple.com>
Cc: david.bolter@gmail.com, Eric Carlson <eric.carlson@apple.com>, Frank Olivier <franko@microsoft.com>, "public-canvas-api@w3.org" <public-canvas-api@w3.org>, public-canvas-api-request@w3.org, HTML Accessibility Task Force <public-html-a11y@w3.org>, public-html-a11y-request@w3.org, surkov.alexander@gmail.com
Message-ID: <OF14105428.07B010D2-ON86257734.005038F5-86257734.0050EA80@us.ibm.com>

Folks, please review the current change request draft for the canvas API.

James, regarding your rect() comment I had the same feelings and am glad
you raised it. I did not like the four coordinates either, yet the 2D
context API does not provide for a rectangle data type and given that they
are trying to get HTML 5 to last call I was not sure we wanted to raise
this issue now.

Eric or Frank  do you think this is something we should raise an issue on
now for the 2D API or push this off to the future as James suggests?

I would like to wrap up the change proposal at the June 7 meeting. So,
please provide feedback this week.

(See attached file: 2dcontext10-May-26.html)

Rich Schwerdtfeger
CTO Accessibility Software Group

             James Craig                                                   
             >                                                          To 
             Sent by:                  Richard                             
             public-canvas-api         Schwerdtfeger/Austin/IBM@IBMUS      
             -request@w3.org                                            cc 
                                       david.bolter@gmail.com, Eric        
                                       Carlson <eric.carlson@apple.com>,   
             05/25/2010 12:31          Frank Olivier                       
             PM                        <franko@microsoft.com>,             
                                       <public-canvas-api@w3.org>, HTML    
                                       Accessibility Task Force            
                                       Re: Draft Revisions to Canvas 2D    
                                       Context API to drive magnification  

Richard Schwerdtfeger wrote:

> The group in attendance (per today's canvas accessibility call)
determined that most accessibility APIs only provide a focus rectangle.
Although the author can draw any shape they like it was agreed that when
the the coordinates are passed for accessibility that they provided as a
best fit rectangle. I will also make this all clear in the next draft for

I can live with that, but I'd like to request that the syntax be such that
it can be extended in the future. e.g., "rect(x1, y1, x2, y2)" instead of
just "x1, y1, x2, y2".

Even if polygons are not supported in the first release, setting a finite
coordinate syntax to only allow for one shape for would make it more
difficult to change once the accessibility APIs are updated to allow for
more precise focus shapes.

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Received on Monday, 31 May 2010 14:44:38 UTC

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