Fixing Issue #75

@@ -262,7 +262,7 @@
         UIGraphicsBeginImageContext(self.frame.size);
         // setup the color of the chart line
         if (chartData.color) {
-            chartLine.strokeColor = [chartData.color CGColor];
+            chartLine.strokeColor = [[chartData.color colorWithAlphaComponent:chartData.alpha]CGColor];
         } else {
             chartLine.strokeColor = [PNGreen CGColor];
             pointLayer.strokeColor = [PNGreen CGColor];
@@ -475,7 +475,7 @@
 
             // create point
             CAShapeLayer *pointLayer = [CAShapeLayer layer];
-            pointLayer.strokeColor   = [chartData.color CGColor];
+            pointLayer.strokeColor   = [[chartData.color colorWithAlphaComponent:chartData.alpha]CGColor];
             pointLayer.lineCap       = kCALineCapRound;
             pointLayer.lineJoin      = kCALineJoinBevel;
             pointLayer.fillColor     = nil;

@@ -19,6 +19,7 @@ typedef PNLineChartDataItem *(^LCLineChartDataGetter)(NSUInteger item);
 @interface PNLineChartData : NSObject
 
 @property (strong) UIColor *color;
+@property (nonatomic) CGFloat alpha;
 @property NSUInteger itemCount;
 @property (copy) LCLineChartDataGetter getData;
 

@@ -22,6 +22,7 @@
     _inflexionPointStyle = PNLineChartPointStyleNone;
     _inflexionPointWidth = 6.f;
     _lineWidth = 2.f;
+    _alpha = 1.f;
 }
 
 @end

@@ -34,6 +34,7 @@
         NSArray * data01Array = @[@60.1, @160.1, @126.4, @262.2, @186.2, @127.2, @176.2];
         PNLineChartData *data01 = [PNLineChartData new];
         data01.color = PNFreshGreen;
+        data01.alpha = 0.3f;
         data01.itemCount = data01Array.count;
         data01.inflexionPointStyle = PNLineChartPointStyleTriangle;
         data01.getData = ^(NSUInteger index) {
@@ -45,6 +46,7 @@
         NSArray * data02Array = @[@20.1, @180.1, @26.4, @202.2, @126.2, @167.2, @276.2];
         PNLineChartData *data02 = [PNLineChartData new];
         data02.color = PNTwitterColor;
+        data02.alpha = 0.5f;
         data02.itemCount = data02Array.count;
         data02.inflexionPointStyle = PNLineChartPointStyleSquare;
         data02.getData = ^(NSUInteger index) {