add highlight circle for radar chart

Charts/Classes/Charts/RadarChartView.swift

@@ -37,6 +37,19 @@ public class RadarChartView: PieRadarChartViewBase
     /// flag indicating if the web lines should be drawn or not
     public var drawWeb = true
 
+    /// flag indicating if highlight circle should be drawn or not
+    public var drawHighlightCircle = true
+
+    public var circleFillColor = UIColor.whiteColor()
+
+    public var circleInnerRadius = CGFloat(3.0)
+
+    public var circleOuterRadius = CGFloat(4.0)
+
+    public var circleStrokeWidth = CGFloat(2.0)
+
+    public var circleStrokeAlpha = CGFloat(0.3)
+
     /// modulus that determines how many labels and web-lines are skipped before the next is drawn
     private var _skipWebLineCount = 0
 

Charts/Classes/Renderers/RadarChartRenderer.swift

@@ -281,8 +281,55 @@ public class RadarChartRenderer: LineScatterCandleRadarChartRenderer
 
             // draw the lines
             drawHighlightLines(context: context, point: _highlightPointBuffer, set: set)
+
+            if (_chart.drawHighlightCircle)
+            {
+                let p = ChartUtils.getPosition(center: center, dist: CGFloat(y) * factor,
+                    angle: sliceangle * CGFloat(j) + _chart.rotationAngle)
+
+                if (!p.x.isNaN && !p.y.isNaN)
+                {
+                    highlightDataDot(context: context, atPoint: p, innerRadius: _chart.circleInnerRadius, outerRadius: _chart.circleOuterRadius, fillColor: _chart.circleFillColor, strokeColor: set.colorAt(0), strokeWidth: _chart.circleStrokeWidth, strokeAlpha: _chart.circleStrokeAlpha)
+                }
+            }
         }
 
         CGContextRestoreGState(context)
     }
+
+    internal func highlightDataDot(context context:CGContext, atPoint point:CGPoint, innerRadius:CGFloat, outerRadius:CGFloat, fillColor:UIColor, strokeColor:UIColor, strokeWidth: CGFloat, strokeAlpha: CGFloat) {
+        // draw inner filled dot
+        let innerPath = CGPathCreateMutable()
+
+        CGPathAddArc(innerPath, nil, CGFloat(point.x), CGFloat(point.y), innerRadius, CGFloat(0), CGFloat(M_PI*2), true)
+        CGPathCloseSubpath(innerPath)
+
+        CGContextSaveGState(context)
+
+        CGContextSetFillColorWithColor(context, fillColor.CGColor)
+        CGContextSetAlpha(context, CGFloat(1.0))
+
+        CGContextBeginPath(context)
+        CGContextAddPath(context, innerPath)
+        CGContextFillPath(context)
+
+        CGContextRestoreGState(context)
+
+        // draw outer stroke dot
+        let outerPath = CGPathCreateMutable()
+        CGPathAddArc(outerPath, nil, CGFloat(point.x), CGFloat(point.y), outerRadius, CGFloat(0), CGFloat(M_PI*2), true)
+        CGPathCloseSubpath(outerPath)
+
+        CGContextSaveGState(context)
+
+        CGContextSetStrokeColorWithColor(context, strokeColor.CGColor)
+        CGContextSetLineWidth(context, strokeWidth)
+        CGContextSetAlpha(context, strokeAlpha)
+
+        CGContextBeginPath(context)
+        CGContextAddPath(context, outerPath)
+        CGContextStrokePath(context)
+
+        CGContextRestoreGState(context)
+    }
 }