[OpenLayers-Users] Hover control sample (share)

[Eric Lemoine]

Hi Amos

What we're trying to do here is come up with code design that doesn't
require creating new controls.

Eric

2009/1/21, Amos Hayes <ahayes at gcrc.carleton.ca>:
>
> We've had to implement separate select and hover functionality on top
> of select feature. If you like, have a look at this work in progress:
>
> http://atlas.gcrc.carleton.ca/kitikmeot/
>
> --
> Amos Hayes
> Geomatics and Cartographic Research Centre
> Carleton University
> ahayes at gcrc.carleton.ca
> +1.613.520.2600x8179
>
> On 21-Jan-09, at 8:34 AM, Alexandre Dube wrote:
>
>> Hey Eric, Ivan,
>>
>>  That issue could occur if both controls would actually change the
>> renderIntent of the feature ( without actually selecting the
>> feature ).
>>
>>  Let's assume that you can only have one feature hovered at a time (
>> only one feature can be hovered by the mouse).  That said, we could
>> have
>> its renderIntent copied to a this.oldRenderIntent local property, then
>> on "beforefeatureunselected" restore the feature with its old
>> renderIntent.  What do you think ?  Simple but that could work.
>>
>>  Also, can we agree on this : 2 SelectFeature controls both doing
>> selection by click or both by hover are not compatible with multiple
>> styling, so let's forget about this for now.
>>
>>  I'll definitively have to try all this soon.
>>
>> Alexandre
>>
>> Eric Lemoine wrote:
>>> Hi
>>>
>>> A first note. The current select feature implementation should
>>> accomodate this use case: two controls on the same layer, one working
>>> on click and the other on hover, only one of them actually changing
>>> the feature style. This is achievable by registering a
>>> beforefeatureselected listener, and have this listener return false.
>>> Adding beforefeatureunselected might help fully accomodate that use
>>> case.
>>>
>>> Now if we want the two controls to do feature styling, we need the
>>> stuff I mentioned previously - per-control selectedFeatures arrays
>>> and
>>> events. But this is unfortunately not sufficient. Use case: two
>>> controls, one working on click and the other on hover, both doing
>>> feature styling but with different render intents. If we have this
>>> sequence "mouse goes over feature, mouse clicks feature, mouse goes
>>> out of feature", then the feature ends up being rendered with the
>>> "default" render intent, while it's still selected from the click
>>> control's perspective. In most cases, this isn't desirable I think.
>>>
>>> At this point I don't have a solution to the above issue.
>>>
>>> Eric
>>>
>>> 2009/1/20, Alexandre Dube <adube at mapgears.com>:
>>>
>>>> Hi Ivan, Eric,
>>>>
>>>>  I was actually thinking a similar idea.  The more I thought about
>>>> it,
>>>> the more I thought about copying/pasting the SelectFeature
>>>> control, make
>>>> some changes to the copy and name it HighlightFeature.  But Eric's
>>>> idea
>>>> is much better.
>>>>
>>>>  Having the control itself know which feature it has selected +
>>>> having
>>>> its own events could enable the possibility of having multiple
>>>> SelectFeature controls for a single layer.  Having both selecting on
>>>> hover and/or click won't matter except for the style and the
>>>> renderIntent applied to the selected feature.  I guess the last
>>>> declared
>>>> control would have the last word of determining those...
>>>>
>>>>  About that, what if we want 2 different colors for each ctrl ?
>>>> Having
>>>> 2 selectfeature ctrls doing the same thing ( hover and click ) is
>>>> not
>>>> very logic, but let's say one select on hover, the other on click,
>>>> it
>>>> would be nice be able to have 2 different styles for each action.
>>>> But
>>>> how could we do that ? (I guess I don't fully understand the whole
>>>> renderIntent stuff yet...  Could we specify a specific
>>>> renderIntent for
>>>> the selectFeature ?  Could "select" be the default value and we
>>>> could be
>>>> able to set our own ?)  To do so without changing the renderIntent
>>>> of
>>>> the feature is to change its style only, without selecting it.
>>>>
>>>>  Ivan's idea (selectOnHover:false) sounds good.  I'd like to see the
>>>> code and try it.  Ivan, could you share what you've done ?  At the
>>>> same
>>>> time, I'd like to try to add events to the control and its
>>>> selectedFeatures array, like Eric said.
>>>>
>>>>  Finally, I would like to know more about what you think about all
>>>> this.
>>>>
>>>> Best regards,
>>>>
>>>> Alexandre
>>>>
>>>> Ivan Grcic wrote:
>>>>
>>>>> On Mon, Jan 19, 2009 at 10:19 PM, Eric Lemoine
>>>>> <eric.c2c at gmail.com> wrote:
>>>>>
>>>>>
>>>>>> On Mon, Jan 19, 2009 at 3:30 PM, Alexandre Dube <adube at mapgears.com
>>>>>> >
>>>>>> wrote:
>>>>>>
>>>>>>
>>>>>>> Hi Eric,
>>>>>>>
>>>>>>> I took a look at the SelectFeature control.  Now I understand
>>>>>>> what you
>>>>>>> meant and it makes sense.  Also, it's also making sense to have
>>>>>>> this
>>>>>>> control
>>>>>>> have the possibility to highlight on hover or on click.
>>>>>>>
>>>>>>> "beforefeaturehighlighted" and "featurehighlighted" events make
>>>>>>> sense,
>>>>>>> but
>>>>>>> a "featureunhighlighted" (or some other term meaning that the
>>>>>>> feature
>>>>>>> was
>>>>>>> highlighted and is now no more) would also be useful.
>>>>>>>
>>>>>>>
>>>>>> Alexandre,
>>>>>>
>>>>>> The more I think about this highlight feature control the more I
>>>>>> think
>>>>>> there's no room for both a select feature and a highlight feature
>>>>>> controls.
>>>>>>
>>>>>>
>>>>>>
>>>>> Same opinion here. We already have a bunch of controls, and now
>>>>> adding
>>>>> two very similar ones...
>>>>>
>>>>> Currently im using slightly modified SelectFeature control, i added
>>>>> one more option to it: selectOnHover, thats how i quickly solved
>>>>> the
>>>>> problem of only highlighting feature without selecting it.
>>>>>
>>>>> If selectOnHover is true, feature is selected&higlighted (select
>>>>> method is called) on hover, if its false feature is only
>>>>> higlighted,
>>>>> not selected.
>>>>>
>>>>>
>>>>>
>>>>>> What causes people trouble is that they can't use two select
>>>>>> feature
>>>>>> controls, one in hover mode and the other in click mode. This is
>>>>>> because once a feature is hovered it is selected, and cannot be
>>>>>> selected again when it is clicked.
>>>>>>
>>>>>> Maybe we could modify the select feature control so that (1) it
>>>>>> optionally uses its own selectedFeatures array, as opposed to
>>>>>> relying
>>>>>> on the layer's, and (b) defines its own "beforefeatureselected",
>>>>>> "featureselected" and "featureunselected" event types. In this
>>>>>> way,
>>>>>> one should be able to use two select feature controls, and get
>>>>>> "featureselected" events, from the first control when features are
>>>>>> hovered and from the second control when features are clicked.
>>>>>>
>>>>>> Tell me what you think,
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>> --
>>>>>> Eric
>>>>>> _______________________________________________
>>>>>> Users mailing list
>>>>>> Users at openlayers.org
>>>>>> http://openlayers.org/mailman/listinfo/users
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>>
>>>> --
>>>> Alexandre Dubé
>>>> Mapgears
>>>> www.mapgears.com
>>>>
>>>>
>>>>
>>
>>
>> --
>> Alexandre Dubé
>> Mapgears
>> www.mapgears.com
>>
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