Add gradient properties to BEMLine and BEMSimpleLineGraphView classes

Author: kattrali

Classes/BEMLine.h

@@ -79,9 +79,15 @@ typedef NS_ENUM(NSInteger, BEMLineAnimation) {
 /// The color of the area above the line, inside of its superview
 @property (strong, nonatomic) UIColor *topColor;
 
+/// A color gradient applied to the area above the line, inside of its superview. If set, it will be drawn on top of the fill from the \p topColor property.
+@property (assign, nonatomic) CGGradientRef topGradient;
+
 /// The color of the area below the line, inside of its superview
 @property (strong, nonatomic) UIColor *bottomColor;
 
+/// A color gradient applied to the area below the line, inside of its superview. If set, it will be drawn on top of the fill from the \p bottomColor property.
+@property (assign, nonatomic) CGGradientRef bottomGradient;
+
 @property (strong, nonatomic) UIColor *xAxisBackgroundColor;
 
 @property (nonatomic) CGFloat xAxisBackgroundAlpha;

Classes/BEMSimpleLineGraphView.h

@@ -197,6 +197,10 @@
 @property (nonatomic) CGFloat alphaBottom;
 
 
+/// Fill gradient of the bottom part of the graph (between the line and the X-axis). When set, it will draw a gradient over top of the fill provided by the \p colorBottom and \p alphaBottom properties.
+@property (assign, nonatomic) CGGradientRef gradientBottom;
+
+
 /// Color of the top part of the graph (between the line and the top of the view the graph is drawn in).
 @property (strong, nonatomic) UIColor *colorTop;
 
@@ -205,6 +209,9 @@
 @property (nonatomic) CGFloat alphaTop;
 
 
+/// Fill gradient of the top part of the graph (between the line and the top of the view the graph is drawn in). When set, it will draw a gradient over top of the fill provided by the \p colorTop and \p alphaTop properties.
+@property (assign, nonatomic) CGGradientRef gradientTop;
+
 /// Color of the line of the graph.
 @property (strong, nonatomic) UIColor *colorLine;
 

Classes/BEMSimpleLineGraphView.m

@@ -441,6 +441,8 @@ - (void)drawLine {
     line.bottomColor = self.colorBottom;
     line.topAlpha = self.alphaTop;
     line.bottomAlpha = self.alphaBottom;
+    line.topGradient = self.gradientTop;
+    line.bottomGradient = self.gradientBottom;
     line.lineWidth = self.widthLine;
     line.lineAlpha = self.alphaLine;
     line.bezierCurveIsEnabled = self.enableBezierCurve;