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[CSS3-UI] Problems with pointer-events draft

From: Kevin Ar18 <kevinar18@hotmail.com>
Date: Wed, 17 Nov 2010 15:47:46 -0500
Message-ID: <SNT110-W4B2F9DC7714208E31C610AA380@phx.gbl>
To: <www-style@w3.org>

In reference to the following section: http://dev.w3.org/csswg/css3-ui/#pointer-events

I figured I would polish up some test cases based on what was put in the CSS3 spec.  However, there are a number of points of confusion that I want to clear up.

First, off, these are only my views on the issue... so I really need some input to see if my reasoning is wrong or not.
Second,
 I apologize for the the aggressive sounding tone; I really don't mean 
it to be that way ... and I appreciate the effort people put into 
working out the details ... however, I just want to get to the heart of 
the issue quickly, so I really hope the original author(s) won't feel 
offended by it. :)


Issue 1. As far as I can tell, the spec does not address the most important issue: whether the svg rectangle should trigger pointer-events.
There was considerable discussion over this very topic in the svg mailing list as well as in various meetings.  The conclusion: it was decided that the topmost/base svg tag should not trigger pointer events -- it should not act like an invisible rectangular object that you can click on.
The relevant discussion is listed here: http://www.w3.org/2010/09/27-fx-minutes.html#action04 under the section: "'pointer-events' and (event) transparency"

Sounds fine... but... I do not see that mentioned in the spec ... which means is this issue still undecided?  is it just an oversight?  am I mis-understanding something?


Issue 2. Why even mention all the pointer-events properties for SVG when they all mean the same thing for the svg tag: "none"?
* According to the SVG spec and the discussions, the svg tag never triggers pointer events -- no matter what the "pointer-events" property is set to.  (There is one exception: the "boundingBox" property from SVGTiny)
* Thus, "pointer-events" has no effect on the svg tag; it only affects it's children. (Again, "boundingBox" is the 1 exception.)
* Example: auto, none, all, visible, visiblePainted, visibleFill, visibleStroke, 
painted, fill, stroke ..... do not affect the base svg tag in any way; 
these properties are merely inherited by it's children.  Note: "auto" is the only property that is different. "auto" changes to "visiblePainted".

So, why even list many of the attributes like "visible", "visiblePainted", "visibleFill", etc... when they have no effect?  Or...,
 does this imply that the CSS3 specs actual means something different?  Do things like 
"visible" and "visiblePainted" work differently than in SVG?  Really, that is probably the most imortant thing; does listing this info in the spec imply that there is something different about it?

Issue 3. There is no way to specify that the svg tag should trigger events.
Based on the points 1 & 2, none
 of the current properties allow the svg tag to trigger events.  I can 
forsee this being a pretty big issue when you specifically want to treat
 the svg element like a drawing surface and capture mouse events.

SVG
 Tiny added another property called "boundingBox" 
(http://www.w3.org/TR/SVGTiny12/interact.html#PointerEventsProperty)  
Should a property like this be added to the CSS3 specs to allow the svg 
tag to trigger events?
 		 	   		  
Received on Wednesday, 17 November 2010 20:48:21 GMT

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