W3C home > Mailing lists > Public > www-svg@w3.org > November 2009

Re: Pointer-events Suggestion

From: Andreas Neumann <a.neumann@carto.net>
Date: Fri, 6 Nov 2009 14:56:50 +0100 (CET)
Message-ID: <37503.141.244.176.119.1257515810.squirrel@webmail.carto.net>
To: "Ryan Maw" <RMaw@Forge-Industrial.com>
Cc: www-svg@w3.org
Hi,

I have no solution other than what Jeff suggested with
SVGSVGElement.getIntersectionList()

But I do also have use-cases besides Ryans use case for an enhanced
pointer-events handling that allows pointer-events to travel through to
all overlapping graphics elements below the mouse-cursor position.

In GIS it is very common having to penetrate through all map layers
(potentially many of them overlapping). As Ryan said, these are not
parent/child/grandchild, etc. relationships but purely spatial or
geometric relationships.

So having an improved pointer-events attribute like "spy"
"catch-and-release" or "penetrate" or whatever it is called, would be very
beneficial for GIS and other applications. This is something I would be
very glad if the SVG WG could pick it up for a later addition to the SVG
spec.

Andreas


On Thu, November 5, 2009 9:27 pm, Ryan Maw wrote:
> Hello, it's my understanding that this is the email address I should
> write to with a suggestion for an enhancement to the pointer-events spec
> in SVG. Please redirect if this is not the case.
>
>
>
> I am working on a SVG application that uses translucent rectangles.
> Clicking or hovering with the mouse pointer over a rectangle fires an
> event related to the specific rectangle. In many circumstances one
> rectangle is partially or completely overlapping another but because
> they are translucent the rectangle in the back can still be seen through
> the one in the front. In this situation it is quite intuitive for a user
> to click on the overlapping region and expect the events associated with
> both rectangles to be triggered. Indeed, this is the desired behaviour I
> want to program for.
>
> The current pointer-events spec allows me to turn off the event capture
> on the upper rectangle by setting pointer-events="none" on this
> rectangle. This way the bottom rectangle receives the events. If I don't
> do this, then only the top rectangle gets the events. I desire BOTH
> rectangles to get the events but there seems to be no simple way to
> achieve this. I imagine setting the upper rectangle to something like:
>
> pointer-events="spy"
>
> This would allow the top rectangle to catch events but then immediately
> release them to propagate to a rectangle beneath - the upper rectangle
> would be "spying" on events. I'm guessing this type of
> translucent-overlapping situation wasn't considered when the
> pointer-events spec was written. Adding a "spy" or "catch-and-release"
> type of behaviour would be valuable. Thank you for considering it.
>
> Ryan Maw, P.Eng.
>
>
>


-- 
Andreas Neumann
http://www.carto.net/neumann/
http://www.svgopen.org/
Received on Friday, 6 November 2009 13:57:43 GMT

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