[OpenLayers-Users] Vector labels at different zoom levels

[Arnd Wippermann]

Hi Jeff,
 
that's the styleMap I use to get the effect. Still in IE the labels with the
font-size = 0px will drawn in very small letters?!
 
Labels are a function of the zoomlevel (context) and the features are a
function of the attribute popClass (UniqueValueRules).
 
var styleMapCapitols;
 
function setStyleMapCapitols()
{
    var context = {
        getFontSize : function(ft){
 
            var diffZ = map.getZoom() - 4;
            var popclass = parseInt(ft.attributes.popclass);
 
            if(popclass > 10 && map.getZoom() > 1)
                return(map.getZoom() + 7 + "px");
            else if(diffZ > 0 && popclass>9)
                return (10 + 1*diffZ +"px")
            else if(diffZ > 0)
                return (8 + 1*diffZ +"px")
            else
                return("0px");
        },
        getName : function (ft){
            return ft.attributes.name;
        }
    };
    var template = {
        strokeColor: "#0000FF",
        strokeOpacity: 1,
        strokeWidth: 3,
        fillColor: "#00AAFF",
        fillOpacity: 1,
        pointRadius: 5,
        pointerEvents: "visiblePainted",
 
        label : "${getName}",
 
        labelOffsetX: "10",
        labelOffsetY: "-10",
        fontColor: "red",
        fontSize: "${getFontSize}",
        fontFamily: "Arial",
        fontWeight: "bold",
        labelAlign: "lt"
    };
    styleMapCapitols = new OpenLayers.StyleMap(new
OpenLayers.Style(template, {context:context}) );
 
    var tata = {fillColor: '#FFAADD', pointRadius: 5, label :
"${getName}",labelOffsetX: "10",labelOffsetY: "20",fontColor:
"yellow",fontSize: "${getFontSize}",fontFamily: "Arial",fontWeight:
"bold",labelAlign: "lt"}
 
    var popArrO = [0.5      ,     0.5  , 0.5      , 0.5      , 0.5      ,
0.5      , 0.5      , 0.5      , 0.75     , 0.75     , 0.75];
    var popArrW = [1        ,     1    , 1        , 1        , 1        , 1
, 2        , 2        , 2        , 2        , 2 ];
    var popArrR = [2        ,     2    , 3        , 3        , 4        , 4
, 5        , 5        , 6        , 7        , 10];
    var popArrC = ['#FFFF00', '#00FF00', '#AA00FF', '#0000FF', '#FF8800',
'#FF0000', '#FFAAAA', '#AAFFAA', '#AAAAFF', '#FF00FF', '#FF00AA'];
 
    var lookup = {};  //popclass beginnt mit 1!
    for(var i=0;i<11;i++)
        lookup[i+1]    = new OpenLayers.Util.applyDefaults({pointRadius:
popArrR[i], fillColor: popArrC[i], fillOpacity: popArrO[i], strokeWidth:
popArrW[i], strokeColor: popArrC[i]}, tata);
 
    styleMapCapitols.addUniqueValueRules("default", "popclass", lookup);
}
setStyleMapCapitols();

an example:
http://gis.ibbeck.de/OLClient/OLClient.asp?KARTE=k10000
 
Arnd

  _____  

Von: users-bounces at openlayers.org [mailto:users-bounces at openlayers.org] Im
Auftrag von Jeff Dege
Gesendet: Montag, 12. April 2010 22:19
An: users at openlayers.org
Betreff: [OpenLayers-Users] Vector labels at different zoom levels



I'm adding some attributes to the GML data I'm using to draw a vector layer,
and have set the label member of the style object to display those
attributes.

 

It works fine, except that it looks lousy when I zoom out.  The labels are
still drawn the same, even though the features may be nearly invisible.

 

How do I turn off the rendering of labels, when the scale exceeds some
threshold?  (Note - I still want to draw the features, I simply don't want
the labels.)

 

I've tried adding a listener to map.movestart, that changes the value of
layer.styleMap.styles['default'.defaultStyle.label, but that only affects
future renderings of the map, it has no effect on the current zoom.

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/openlayers-users/attachments/20100413/e9428795/attachment.html