As in example http://openlayers.org/dev/examples/graphic-name.html ... I tried drawing my feature geometry as a flag but I realized that OpenLayers always uses the centroid of the geometry to place the feature at the specified point(latitude/longitude), whereas I wish the base of the flag to be placed at the specified point. Changing the value of Renderer.symbol did not make any effect neither did the graphicXOffset/graphicYOffset.
//my flag geometry
OpenLayers.Renderer.symbol.flag = [0, 0, 0, 140, 120, 140, 120, 60, 4, 60, 4, 0, 0, 0];
//create vector layer with default and select styles
myVectorLayer = new OpenLayers.Layer.Vector("Flag Geometry", {
renderers: renderer,
isBaseLayer: true,
graphicName: flag,
rotation: 180,
pointRadius: 15,
projection: new OpenLayers.Projection("EPSG:900913"),
styleMap: new OpenLayers.StyleMap({
"default": new OpenLayers.Style(OpenLayers.Util.applyDefaults({
fillColor: "red",
strokeColor: "gray",
label: "${label}",
fontColor: "${favColor}",
fontSize: "12px",
fontFamily: "Courier New, monospace",
fontWeight: "bold",
labelYOffset: 2 //for flag
}, OpenLayers.Feature.Vector.style["default"])),
"select": new OpenLayers.Style(OpenLayers.Util.applyDefaults({
}, OpenLayers.Feature.Vector.style["select"]))
})
});
var flag = new OpenLayers.Geometry.Point(latitude, longitude);
var flagFeature = new OpenLayers.Feature.Vector(flag);
myVectorLayer.addFeatures([flagFeature]);
To overcome this base point problem I changed the drawing method as follows:
myVectorLayer = new OpenLayers.Layer.Vector("Flag Geometry", {
renderers: renderer,
isBaseLayer: true,
projection: new OpenLayers.Projection("EPSG:900913"),
styleMap: new OpenLayers.StyleMap({
"default": new OpenLayers.Style(OpenLayers.Util.applyDefaults({
fillColor: "red",
strokeColor: "gray",
label: "${label}",
fontColor: "${favColor}",
fontSize: "12px",
fontFamily: "Courier New, monospace",
fontWeight: "bold",
labelYOffset: 2 //for flag
}, OpenLayers.Feature.Vector.style["default"])),
"select": new OpenLayers.Style(OpenLayers.Util.applyDefaults({
}, OpenLayers.Feature.Vector.style["select"]))
})
});
var pointList = [];
var xs = [0, 0, 240, 240, 8, 8, 0];
var ys = [0, 280, 280, 120, 120, 0, 0];
for(var p=0; p<6; ++p) {
var newPoint = new OpenLayers.Geometry.Point(camera.get('latitude') + xs[p],
camera.get('longitude') + ys[p]);
pointList.push(newPoint);
}
pointList.push(pointList[0]);
var linearRing = new OpenLayers.Geometry.LinearRing(pointList);
var flagVector = new OpenLayers.Feature.Vector(
new OpenLayers.Geometry.Polygon([linearRing]));
flagVector.attributes= {
label: 'label',
favColor: 'blue', //favorite color
align: "cm"
};
myVectorLayer.addFeatures([flagVector]);
This though will make the geometry zoom with map zoom not as the previous way.