Bug 9061 - allow image maps on the canvas element.
allow image maps on the canvas element.
Status: CLOSED WONTFIX
Product: HTML WG
Classification: Unclassified
Component: pre-LC1 HTML Canvas 2D Context (editor: Ian Hickson)
unspecified
PC Windows NT
: P3 normal
: ---
Assigned To: Ian 'Hixie' Hickson
HTML WG Bugzilla archive list
: a11y, a11ytf, a11y_canvas, NE, TrackerIssue
Depends on:
Blocks:
  Show dependency treegraph
 
Reported: 2010-02-18 10:46 UTC by steve faulkner
Modified: 2012-11-15 17:16 UTC (History)
13 users (show)

See Also:


Attachments

Note You need to log in before you can comment on or make changes to this bug.
Description steve faulkner 2010-02-18 10:46:37 UTC
Allow image maps to be added to the canvas element:
<canvas usemap="#test">

This will make it easy for developers to add focusable interactive regions to canvas.
Comment 2 Ian 'Hixie' Hickson 2010-03-31 21:29:38 UTC
EDITOR'S RESPONSE: This is an Editor's Response to your comment. If you are satisfied with this response, please change the state of this bug to CLOSED. If you have additional information and would like the editor to reconsider, please reopen this bug. If you would like to escalate the issue to the full HTML Working Group, please add the TrackerRequest keyword to this bug, and suggest title and text for the tracker issue; or you may create a tracker issue yourself, if you are able to do so. For more details, see this document:
   http://dev.w3.org/html5/decision-policy/decision-policy.html

Status: Rejected
Change Description: no spec change
Rationale: Unfortunately if we provide this we will be causing authors huge headaches, because while it would be possible to use canvas with image maps for the most trivial of pictures (pictures much better rendered on the server side), it becomes vastly more complicated to use image maps to do the slightest dynamic work once the canvas is made in any way more advanced. For example, any use of transforms, any use of large strokes, anything animated, etc, quickly makes it inordinately difficult to use image maps. In the meantime, all the use cases of image maps are trivially handled today using the API.

Therefore I think it would be a design mistake to do this.
Comment 3 steve faulkner 2010-03-31 21:54:24 UTC
(In reply to comment #2)
> EDITOR'S RESPONSE: This is an Editor's Response to your comment. If you are
> satisfied with this response, please change the state of this bug to CLOSED. If
> you have additional information and would like the editor to reconsider, please
> reopen this bug. If you would like to escalate the issue to the full HTML
> Working Group, please add the TrackerRequest keyword to this bug, and suggest
> title and text for the tracker issue; or you may create a tracker issue
> yourself, if you are able to do so. For more details, see this document:
>    http://dev.w3.org/html5/decision-policy/decision-policy.html
> 
> Status: Rejected
> Change Description: no spec change
> Rationale: Unfortunately if we provide this we will be causing authors huge
> headaches, because while it would be possible to use canvas with image maps for
> the most trivial of pictures (pictures much better rendered on the server
> side), it becomes vastly more complicated to use image maps to do the slightest
> dynamic work once the canvas is made in any way more advanced. For example, any
> use of transforms, any use of large strokes, anything animated, etc, quickly
> makes it inordinately difficult to use image maps. In the meantime, all the use
> cases of image maps are trivially handled today using the API.
> 
> Therefore I think it would be a design mistake to do this.
> 

Comment 4 Maciej Stachowiak 2010-03-31 22:17:21 UTC
http://www.w3.org/html/wg/tracker/issues/105
Comment 5 Maciej Stachowiak 2010-03-31 22:20:44 UTC
For what it's worth: I don't believe the WebKit project would object to allowing image maps on <canvas>. However, we would likely suggest in that case that <area> should be extended with a new shape that can specify an arbitrary bezier path.
Comment 6 Steve Jorgensen 2010-05-03 07:53:49 UTC
I disagree with the rejection response.  Just because there are many complex cases to which image maps would be hard to apply does not mean there are not a plethora of simple cases for which image maps would be extremely handy.

Using a mouse click to zoom in is a great example of where this would be handy.  Since browser-interoperable mouse position determination is so incredibly complicated, an image map makes a nice, simple solution, especially where (as is likely the case) the precision of the click position need not be extremely precise.

The only potentially convincing counterargument I can think of to adding image maps to canvas elements is that the same thing can be accomplished by overlaying transparent, absolutely-positioned anchors.  That is, however, a very kludgey way to handle it, and does not trivially deal with non-rectangular areas.
Comment 7 David Bolter 2010-05-07 15:57:10 UTC
(In reply to comment #6)
> The only potentially convincing counterargument I can think of to adding image
> maps to canvas elements is that the same thing can be accomplished by
> overlaying transparent, absolutely-positioned anchors.  That is, however, a
> very kludgey way to handle it, and does not trivially deal with non-rectangular
> areas.

Yeah that has been bounced around.
E.g. http://lists.w3.org/Archives/Public/public-html/2010Feb/0186.html
Comment 8 Michael Cooper 2010-08-31 14:06:03 UTC
http://lists.w3.org/Archives/Public/public-html-a11y/2010Aug/0124.html

The bug triage sub-team believes the HTML A11Y TF should take up this bug. Additional notes may follow in a separate comment.
Comment 9 Michael Cooper 2010-09-14 16:01:32 UTC
bug triage sub-team understands this is open for counter-proposals and needs no further tracking at TF level at this time
Comment 10 Martin Kliehm 2010-11-30 12:12:55 UTC
This bug has been escaleted in ISSUE 105
Comment 11 Léonie Watson 2012-11-15 17:16:15 UTC
Comment via Rich Schwerdtfeger: We are not using this for canvas.