I just went through this myself.
In my case, I was already taking advantage of using vector styling context
(similar to this example:
http://www.openlayers.org/dev/examples/styles-context.html
http://www.openlayers.org/dev/examples/styles-context.html )
I found that the points that are used for the vertices have a property
called _sketch. This allowed me to pick out those particular points and
style them accordingly.
This solution may be overkill for what you are looking for though
/* styling for the vector layers */
/* different styles to apply depending on the type of vector */
vectorTypeLookup[normal] = { fillColor: '#ee9900', fillOpacity:
0.4, strokeWidth: 1.0, strokeColor: '#ee9900', pointRadius: 6 };
vectorTypeLookup[polygon] = { fillColor: '#ee9900', fillOpacity:
0.4, strokeWidth: 1.0, strokeColor: '#ee9900', pointRadius: 6 };
vectorTypeLookup[point] = { fillColor: '#ee9900', fillOpacity:
0.4, strokeWidth: 2.0, strokeColor: '#ee9900', pointRadius: 8 };
vectorTypeLookup[line] = { fillColor: '#ee9900', fillOpacity: 0.4,
strokeWidth: 3.0, strokeColor: '#ee9900', pointRadius: 6 };
vectorTypeLookup[label] = { fillColor: '#ee9900', fillOpacity:
0.4, strokeWidth: 1.0, strokeColor: '#ee9900', pointRadius: 3,
labelAlign: tr, fontSize: 12px, fontColor: #005596,
fontWeight: bold, labelSelect: true
};
vectorTypeLookup[sketch] = { fillColor: '#005596', fillOpacity:
0.4, strokeWidth: 3.0, strokeColor: '#005596', pointRadius: 6 };
/* create a template that will use the functions to get the
appropriate colour */
var vectorTemplate = { fillColor: ${getFillColour}, fillOpacity:
${getFillOpacity}, strokeWidth: ${getStrokeWidth}, strokeColor:
${getStrokeColour}, pointRadius: ${getPointRadius},
labelAlign: ${getLabelAlign}, fontSize: ${getFontSize},
fontColor: ${getFontColour}, fontWeight: ${getFontWeight}, labelSelect:
${getLabelSelect}, label: ${getLabel}
};
/*
the style will use the context when determining the appropriate
style - see the vectorStyle declaration
- ex. drawing a polygon on the drawLayer.
1) drawLayer is assigned the vectorStyleMap to detrmine the style
2) The vectorStyleMap uses the vectorStyle rule to know what style
properties are available
3) The vectorStyle refers to vectorTemplate to configure the
different properties (fillColor, strokeWidth). The vectorContext is used to
evaluate the ${...} items
4) Each function in vectorContext returns the appropriate property
value
*/
var vectorContext = {
getVectorType: function(feature) {
try {
if (typeof (feature._sketch) !== undefined) {
return vectorTypeLookup[sketch]; /* used when
modifying items */
} else if
(feature.geometry.CLASS_NAME.search(/polygon$/i) = 0) {
return vectorTypeLookup[polygon];
} else if (feature.geometry.CLASS_NAME.search(/point$/i)
= 0 typeof (feature.attributes.label) !== undefined) { /* labels are
point vectors */
return vectorTypeLookup[label];
} else if (feature.geometry.CLASS_NAME.search(/point$/i)
= 0) {
return vectorTypeLookup[point];
} else if
(feature.geometry.CLASS_NAME.search(/linestring$/i) = 0) {
return vectorTypeLookup[line];
} else {
/*who knows */
return vectorTypeLookup[normal];
}
} catch (e) { return vectorTypeLookup[normal]; }
},
getFillColour: function(feature) { return
vectorContext.getVectorType(feature).fillColor; },
getFillOpacity: function(feature) { return
vectorContext.getVectorType(feature).fillOpacity; },
getStrokeWidth: function(feature) { return
vectorContext.getVectorType(feature).strokeWidth; },
getStrokeColour: function(feature) { return
vectorContext.getVectorType(feature).strokeColor; },
getPointRadius: function(feature) { return
vectorContext.getVectorType(feature).pointRadius; },
getLabel: function(feature) {
if (typeof (feature.attributes.label) != undefined) {
/* return the label */
return feature.attributes.label;
} else {
return ; /* nothing */
}
},
getLabelAlign: function(feature) {
try {
return vectorContext.getVectorType(feature).labelAlign;
} catch (e) { return ; }
},
getFontSize: function(feature) {
try {
return vectorContext.getVectorType(feature).fontSize;
} catch (e) { return ; }
