public override function findDataPoints(x:Number, y:Number):Array {
   var result:Array = []; //array of HitData

   // Ignore mouse points outside of the data region of the chart. (e.g. on the axis labels)
   if (!dataRegion.contains(x, y)) {
      return result;
   }

   // The x,y coordinates given to findDataPoints are relative to the LineChart. Make them local to
   // the component which holds the data series
   var mouseLoc:Point = new Point(x - _seriesHolder.x, y - _seriesHolder.y);

   // Loop through each LineSeries displayed on the chart
   // This can also work with AreaSeries, etc. without too much modification
   for each (var line:LineSeries in this.series) {

      if (!line.visible) {
         continue;
      }

      // Get the value on the chart at the given mouse point
      var valueAtMouse:Array = line.localToData(mouseLoc);

      // Loop through the data points for this line and find the closest data point to the left of the mouse.
      // NOTE: This is specific to a "step" chart. For a regular "segment" chart, you'll need to find the 2 
      // points on either side of the mouse and interpolate the value.
      var last:LineSeriesItem = null;
      for each (var item:LineSeriesItem in line.items) {
         if (item.xValue < valueAtMouse[0]) {
            last = item;
         }
         else {
            break;
         }
      }

      // If we found a data point and the line is within 50 pixels of the mouse vertically, we'll show a data tip
      // If you want to show data tips for ALL points at a specific x-value, just remove the vertical proximity check
      if (last && Math.abs(last.y - mouseLoc.y) < 50) {

         // We need to clone the data point that we found and modify its xValue to match that of our mouse
         // location. This way the popup data tip that displays will show the xValue at the mouse instead of
         // the nearest data point
         var hitPoint:LineSeriesItem = LineSeriesItem(last.clone());
         hitPoint.x = last.x;
         hitPoint.y = last.y;
         hitPoint.xValue = Math.floor(valueAtMouse[0]);
         hitPoint.yValue = last.yValue;

         // Compute the distance between the mouse and the data point.
         var dist:Number = Math.sqrt(Math.pow(mouseLoc.x - last.x, 2) + Math.pow(mouseLoc.y - last.y, 2));

         // Create a HitData object which the data tip will use. I ignore the ID param for now since I didn't
         // find it useful. If you need to implement it, see LineSeries.createDataID
         var hitData:HitData = new HitData(0, dist, x, hitPoint.y + _seriesHolder.y, hitPoint);

         // Make the data tip color scheme match the line. If you do anything fancy with your line coloring
         // you'll probably have to modify this.
         var stroke:SolidColorStroke = SolidColorStroke(line.getStyle('lineStroke'));
         hitData.contextColor = stroke.color;

         // Create the function which actually gives the text value for the data tip. Normally the LineSeries
         // constructs its own HitData objects and is responsible for supplying this function.
         hitData.dataTipFunction = makeDataTipFunction(line);

         result.push(hitData);
      }
   }

   return result;
}

protected function makeDataTipFunction(line:LineSeries):Function {

   // Create a data tip function for a given LineSeries. The code
   // below was copied almost exactly from LineSeries.formatDataTip
   return function(hd:HitData):String {
      var txt:String = "";

      var n:String = line.displayName;
      if (n && n != "") {
         txt += "<b>" + n + "</b><BR/>";
      }

      var xName:String = line.dataTransform.getAxis(CartesianTransform.HORIZONTAL_AXIS).displayName;

      if (xName != "") {
         txt += "<i>" + xName+ ":</i> ";
      }

      txt += line.dataTransform.getAxis(CartesianTransform.HORIZONTAL_AXIS).formatForScreen(
            LineSeriesItem(hd.chartItem).xValue) + "\n";

      var yName:String = line.dataTransform.getAxis(CartesianTransform.VERTICAL_AXIS).displayName;
      if (yName != "") {
         txt += "<i>" + yName + ":</i> ";
      }

      txt += line.dataTransform.getAxis(CartesianTransform.VERTICAL_AXIS).formatForScreen(
            LineSeriesItem(hd.chartItem).yValue) + "\n";

      return txt;
   }
}