17563 2012-06-21 01:56:53 +0000 Forbid use of canvas for decoration 2012-09-28 18:08:25 +0000 1 1 1 Unclassified HTML WG HTML Canvas 2D Context unspecified All All RESOLVED WONTFIX P2 normal --- 1 res-html cabanier cabanier glenn ian jens mike public-html-admin public-html-wg-issue-tracking silviapfeiffer1 public-html-bugzilla oldest_to_newest 69305 0 res-html 2012-06-21 01:56:53 +0000 (coming from http://forums.whatwg.org/bb3/viewtopic.php?f=3&t=5016) The spec for the canvas element states: "The canvas element provides scripts with a resolution-dependent bitmap canvas, which can be used for rendering graphs, game graphics, or other visual images on the fly." One could interpret that "other visual images" implies *decorative* images, too. I suggest to explicitly mention that the canvas element should/must not be used for pure decorative images. Maybe similar to the section "A purely decorative image that doesn't add any information", which states for the img element: "If an image is decorative but isn't especially page-specific — for example an image that forms part of a site-wide design scheme — the image should be specified in the site's CSS, not in the markup of the document." Random examples for what could be considered as decorative use of canvas (if used as background animation in webpages *not about* canvas (or the animation) itself): · http://timothypoon.com/blog/demos/canvas-particle-parallax/ · http://radikalfx.com/files/anibg/ · http://www.go2script.com/items/style/14/25/dark_blue · http://hernan.amiune.com/labs/particle-system/hello-world.html 69308 1 glenn 2012-06-21 05:32:34 +0000 purely decorative use of canvas is a legitimate use case 69371 2 zcorpan 2012-06-25 05:04:22 +0000 The spec should be clearer about whether canvas-for-decoration is OK or not, I think. 69372 3 glenn 2012-06-25 05:10:17 +0000 if the spec doesn't prohibit it, then it's permitted 69378 4 zcorpan 2012-06-25 06:57:09 +0000 It's usually the other way around, actually. Please leave the bug open. 69381 5 glenn 2012-06-25 14:39:53 +0000 (In reply to comment #4) > It's usually the other way around, actually. Please leave the bug open. Really? You think specs constrain their applicability of use by default? You and I must be reading different specs then. Any spec that arbitrarily constraints its applicability of use is not going to be very useful for the open web platform (or much else for that matter). The fundamental purpose of canvas is to allow authoring an image using procedural means (JS), instead of declarative means (via raster or vector graphics). As such, its applicability of use should be close if not equivalent to that of an image element. Are you arguing otherwise? Since you ask to leave this open, I will defer further resolution to the editor. 70531 6 contributor 2012-07-18 16:00:01 +0000 This bug was cloned to create bug 18031 as part of operation convergence. 72074 7 silviapfeiffer1 2012-08-11 05:58:33 +0000 Moved to canvas component. 72080 8 ian 2012-08-11 21:19:44 +0000 Silvia, did you mean to assign this to me? (If so, please move it to the WHATWG product's HTML component.) 72083 9 silviapfeiffer1 2012-08-12 00:06:08 +0000 No I didn't mean to, sorry. But you're still the default assignee for HTML Canvas 2D - need to change this. 72171 10 cabanier 2012-08-14 22:59:00 +0000 (In reply to comment #2) > The spec should be clearer about whether canvas-for-decoration is OK or not, I > think. I assume that you're referring to the section "A purely decorative image that doesn't add any information but is still specific to the surrounding content" in http://www.w3.org/TR/2008/WD-html5-20080610/embedded0.html. That particular part of the spec describes what the 'alt' attribute should contain. This does not prohibit using an image for purely decorative means. (Also, notice the 'in general' which does not prohibit decorative images). > "The canvas element provides scripts with a resolution-dependent bitmap canvas, > which can be used for rendering graphs, game graphics, or other visual images > on the fly." This description is talking about the content of the canvas. It's not saying how you can use that content (be it as a normal image or a decorative one as described in the image spec ) 72625 11 cabanier 2012-08-23 19:57:16 +0000 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 74767 12 silviapfeiffer1 2012-09-28 09:47:23 +0000 Would you mind if we applied the WHATWG fix for this, as it is simple: https://github.com/w3c/html/commit/923c9ad84e7eb6d0b4a04cde1465055d9007b437 74823 13 cabanier 2012-09-28 18:08:25 +0000 (In reply to comment #12) > Would you mind if we applied the WHATWG fix for this, as it is simple: > > https://github.com/w3c/html/commit/923c9ad84e7eb6d0b4a04cde1465055d9007b437 That change was already integrated on Sept 18. I'm unsure if it's related to this bug.