new boolean property on linechart to toggle mouseover dots

spec/line-chart-spec.js

@@ -122,6 +122,20 @@ describe('dc.lineChart', function() {
             });
         });
 
+        describe('data point highlights and refs off', function () {
+            beforeEach(function () {
+                chart.title(function (d) { return d.value; });
+                chart.brushOn(false).xyTipsOn(false).render();
+            });
+            it('should not generate per data points', function () {
+                expect(chart.selectAll('circle.dot').size())toBe(0);
+            });
+            it('should not generate x and y refs', function () {
+                expect(chart.selectAll('path.xRef').size()).toBe(0);
+                expect(chart.selectAll('path.yRef').size()).toBe(0);
+            });
+        });
+
         describe('data point highlights', function () {
             beforeEach(function () {
                 chart.title(function (d) { return d.value; });

src/line-chart.js

@@ -52,6 +52,7 @@ dc.lineChart = function (parent, chartGroup) {
     var _tension = 0.7;
     var _defined;
     var _dashStyle;
+    var _xyTipsOn = true;
 
     _chart.transitionDuration(500);
     _chart._rangeBandPadding(1);
@@ -233,7 +234,7 @@ dc.lineChart = function (parent, chartGroup) {
     }
 
     function drawDots(chartBody, layers) {
-        if (!_chart.brushOn()) {
+        if (!_chart.brushOn() && _chart.xyTipsOn()) {
             var tooltipListClass = TOOLTIP_G_CLASS + '-list';
             var tooltips = chartBody.select('g.' + tooltipListClass);
 
@@ -338,6 +339,20 @@ dc.lineChart = function (parent, chartGroup) {
         }
     }
 
+    /**
+     #### .xyTipsOn([boolean])
+     Turn on/off the mouseover behavior of an individual data point which renders a circle and x/y axis
+     dashed lines back to each respective axis.  This is ignored if the chart brush is on (`brushOn`)
+     Default: true
+     */
+    _chart.xyTipsOn = function (_) {
+        if (!arguments.length) {
+            return _xyTipsOn;
+        }
+        _xyTipsOn = _;
+        return _chart;
+    };
+
     /**
     #### .dotRadius([dotRadius])
     Get or set the radius (in px) for dots displayed on the data points. Default dot radius is 5.