[OpenLayers-Dev] stop propagation in handlers

[Pierre GIRAUD]

On Tue, Feb 26, 2008 at 7:00 PM, Tim Schaub <tschaub at openplans.org> wrote:
> Hey-
>
>
>  Pierre GIRAUD wrote:
>  > Hello,
>  >
>  > In most handlers, in fact those dealing with browser events, we need,
>  > in most case need to stop event propagation, to prevent weird
>  > behaviors. However, I think that propagation stop isn't complete.
>  > Returning false to an event callback doesn't to be enough.
>  > In my code, I play with vector symbols using SVG 'symbol' and 'use'
>  > tags. The latter have a 'href' property with a reference to the
>  > symbol. Ctrl+Click on the corresponding feature on the map opens a new
>  > tab in FF.
>
>  Yeah, three kinds of stopping really.  The stopDown property is about
>  stopping other listeners for the same events instance (same dom element
>  in the case of browser events) from getting notified.
Understood.

>
>  Do we want a separate property for stopping events from bubbling to
>  other dom elements?
I don't really know.

>
>  How about stopping the browser default for an event?
The following example includes shows three different feature using the
same symbol. If you try ctrl+click on each, the third one is the only
one that doesn't open a new tab.
http://dev.openlayers.org/sandbox/camptocamp/vectorSymbols/examples/svg/symbol_catalog3.svg

It seems like preventing browser defaut has no effect in that particular case.
By stopping the browser default, did you mean calling preventDefault ?

>
>  I think lumping all three of those in one property (on a handler) might
>  come back to haunt us.

Agreed.

Any suggestion ?

Pierre

>
>  Tim
>
>
>
>  > I need this Ctrl+Click because I need to select several feature.
>  > http://dev.openlayers.org/sandbox/camptocamp/vectorSymbols/examples/select-feature.html
>  >
>  > I'm not really convinced by this solution but I would prefer something
>  > like following. It seems to work fine for me in my example.
>  >
>  >      mousedown: function(evt) {
>  >          this.down = evt.xy;
>  > -        return this.handle(evt) ? !this.stopDown : true;
>  > +        if (this.handle(evt)) {
>  > +            if (this.stopDown) {
>  > +                OpenLayers.Event.stop(evt, true);
>  > +            }
>  > +            return !this.stopDown;
>  > +        } else {
>  > +            return true;
>  > +        }
>  >      },
>  >
>  > Any comment on that ?
>  >
>  > Regards,
>  > Pierre
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