I'm sure this can be improved upon, but this method allows a user to use the Line tool to draw what would represent a radius, starting at the center point and ending at the edge of the circle. The geometry (the 2 end points) of that line is then used to generate a circle and place it on the map. I hope someone else can make use of this.
function addCircleToMap(geometry){ //the geometry that get�??s passed in contains the 2 points that define the line that was draw.
drawingToolbar.deactivate();
map.showZoomSlider();
var symbol; // the symbol is just the line (pen) that will be used to draw the shape
symbol = new esri.symbol.SimpleFillSymbol(esri.symbol.SimpleFillSymbol.STYLE_SOLID, new esri.symbol.SimpleLineSymbol(esri.symbol.SimpleLineSymbol.STYLE_SOLID, new dojo.Color([239, 62, 66, .6]), 3), new dojo.Color([240, 223, 186, 0.25]));
var circleGeometry = new esri.geometry.Polygon(new esri.SpatialReference({wkid:102100}));
var points = new Array();
var degree;var i=0;var edgeX, edgeY,tmpPoint,path
//since mercator projection is expressed in meters, we can use some simple math to look at the 2 points in terms of a right triangle sitting on lat/lon lines
//then use the pythagorean theorem to get the hypotenuse (distance) between the 2 points
var dist = Math.sqrt(Math.pow((geometry.paths[0][0][0] - geometry.paths[0][1][0]),2) + Math.pow((geometry.paths[0][0][1] - geometry.paths[0][1][1]),2));
while(i<361){ //now, with our 2 points and the distance, we can loop 360 times and calculate 360 points around the circumference of our soon-to-be circle.
degree = i * (Math.PI / 180);
edgeX = geometry.paths[0][0][0] + Math.cos(degree) * dist;
edgeY = geometry.paths[0][0][1] + Math.sin(degree) * dist;
points.push([edgeX,edgeY]); //push the new point into the point array
i++;
}
//put the point array into the polygon object
circleGeometry.addRing(points);
//create a graphic object using our new polygon/point array
var graphic = new esri.Graphic(circleGeometry, symbol);
try {
bufferLayer.clear();
map.removeLayer(bufferLayer);
}
catch (err) { } //this layer won't always exist, so we'll need to check.
bufferLayer = new esri.layers.GraphicsLayer();
bufferLayer.add(graphic); // add the graphic to the graphics layer
map.addLayer(bufferLayer); //and add the new layer to the map
}
