[OpenLayers-Users] Select style for point features

[Olivier THIERRY]

2010/3/2 Alexandre Dube <adube at mapgears.com>:
> Olivier,
>
> The way to defined your "default" symbolizer with the applyDefaults method
> is correct, but you didn't do so with your "select" symbolizer. In order for
> a point to be drawn, it needs more than these two properties (like
> pointRadius for example). Try using applyDefaults there too.
>
> Then, remove the style from your point features too. In order for a feature
> to change style automatically when selected, it has to be done with the
> StyleMap or manually. If you set a symbolizer (style) directly to your
> feature, that's the only style it's going to have regardless of any stylemap
> defined.
>
> // are you saying that with this, points don't show at all when unselected ?
> Normally, it shouldn't.
> var feature = new OpenLayers.Feature.Vector(point);
>
> Kind regards,
>
> Alexandre
>
>
> Olivier THIERRY wrote:
>>
>> Hi,
>>
>> I have to draw routes on a map. I need points for the steps of the
>> route and lines between the steps.
>> I could make it work, but now I need to highlight these lines and points.
>> Actually I need to change the colour of either lines or points when
>> they are selected in a list outside the map or clicked on the map.
>>
>> To do this, I added a SelectFeature control to the layer containing the
>> routes.
>>
>> I could make it work for lines by adding the following style map to
>> the routes layer :
>>
>>        var symbolizer = OpenLayers.Util.applyDefaults(
>>                {
>>                        fillColor: "#0000FF"
>>                        , strokeColor: "#2A2AFF"
>>                        , strokeWidth: 2
>>                }
>>                , OpenLayers.Feature.Vector.style["default"]);
>>
>>        var styles = new OpenLayers.StyleMap({
>>                "default": symbolizer,
>>                "select": {
>>                        fillColor: "red"
>>                        , strokeColor: "red"
>>                }
>>        });
>>
>> But I can't make it work with points.
>>
>> I create the points this way :
>>
>> var point = new OpenLayers.Geometry.Point(lon, lat, 0);
>> point.transform(map.displayProjection, map.projection);
>> var styleSite = OpenLayers.Util.extend({},
>> OpenLayers.Feature.Vector.style['default']);
>> styleSite.strokeColor = "blue";
>> styleSite.fillColor = "blue";
>> styleSite.pointRadius = 3;
>> styleSite.strokeLinecap = "square";
>> var feature = new OpenLayers.Feature.Vector(point, null, styleSite);
>>
>> The points display OK, but colour doesn't change when I select the point.
>> I think my problem deals with style, but I can't find what is wrong.
>> Note I had to set the style for point vector. If I don't do this, it
>> doesn't diplay. I find this strange since I don't need to do this for
>> line feature !
>>
>> Any idea what I did wrong ?
>>
>> Regards,
>>
>> Olivier
>> _______________________________________________
>> Users mailing list
>> Users at openlayers.org
>> http://openlayers.org/mailman/listinfo/users
>>
>
>
> --
> Alexandre Dubé
> Mapgears
> www.mapgears.com
>
>

For what I understood, when you define a "default" style, other styles
extend this default style. So when defining a "select" style for
example, you just have to set the style attributes that you want to be
different from default style. And it works very well indeed. I read
this there : http://trac.openlayers.org/wiki/Styles#UsingPropertyStyles

Anyway, I just found where my problem comes from. Actually I use rules
with my style map, this way :

	var lookupSens = {
	    "aller": {strokeDashstyle: "solid"},
	    "retour": {strokeDashstyle: "dash"}
	};
	styles.addUniqueValueRules("default", "sens", lookupSens);

This rule helps me to have a different style for journey and return journey.
But since it has no sense for points (just for lines), I don't have
the "sens" property on the point I add to the layer, and it looks like
it causes some problems !
If I remove this rule, the points print OK. But I really need this
rule, so I can't remove it.

Do you know if there is a way to tell OpenLayers to apply the rule
only for some elements of the layer ? Or another workaround for this ?

Regards,

Olivier