Adds gradientFill to C4Shape

C4/UI/C4Image.swift

@@ -78,6 +78,13 @@ public class C4Image: C4View, NSCopying {
 
     //MARK: Initializers
 
+    /// Initializes an empty C4Image
+    public override init() {
+        super.init()
+        let uiimage = UIImage()
+        self.view = ImageView(image: uiimage)
+    }
+
     /// Initializes a new C4Image using the specified filename from the bundle (i.e. your project), it will also grab images
     /// from the web if the filename starts with http.
     ///

C4/UI/C4Shape.swift

@@ -22,7 +22,8 @@ import UIKit
 
 /// C4Shape is a concrete subclass of C4View that draws a bezier path in its coordinate space.
 public class C4Shape: C4View {
-
+    var clearContents: CGImageRef!
+
     internal class ShapeView : UIView {
         var shapeLayer: C4ShapeLayer {
             get {
@@ -56,6 +57,11 @@ public class C4Shape: C4View {
         lineWidth = 1
         lineCap = .Round
         lineJoin = .Round
+
+        let i = C4Image()
+        i.size = C4Size(1,1)
+        clearContents = i.render()!.cgimage
+        shapeLayer.contents = clearContents
     }
 
     /// Initializest a new C4Shape from a specified C4Path.
@@ -71,7 +77,46 @@ public class C4Shape: C4View {
         updatePath()
         adjustToFitPath()
     }
-
+
+    public convenience init(_ shape: C4Shape) {
+        self.init()
+        let disable = C4ShapeLayer.disableActions
+        C4ShapeLayer.disableActions = true
+        self.path = shape.path
+        shapeLayer.path = path?.CGPath
+        self.frame = shape.frame
+        self.lineWidth = shape.lineWidth
+        self.lineDashPhase = shape.lineDashPhase
+        self.lineCap = shape.lineCap
+        self.lineJoin = shape.lineJoin
+        self.lineDashPattern = shape.lineDashPattern
+        self.fillColor = shape.fillColor
+        self.strokeColor = shape.strokeColor
+        self.strokeStart = shape.strokeStart
+        self.strokeEnd = shape.strokeEnd
+        self.miterLimit = shape.miterLimit
+        updatePath()
+        adjustToFitPath()
+        C4ShapeLayer.disableActions = disable
+    }
+
+    public var gradientFill: C4Gradient? {
+        didSet {
+            guard gradientFill != nil else {
+                shapeLayer.contents = clearContents
+                return
+            }
+            if mask == nil  {
+                let m = C4Shape(self)
+                m.fillColor = black
+                m.strokeColor = black
+                mask = m
+            }
+            fillColor = nil
+            shapeLayer.contents = gradientFill?.render()?.cgimage
+        }
+    }
+
     /// The path defining the shape to be rendered. If the path extends outside the layer bounds it will not automatically
     /// be clipped to the layer. Defaults to nil. Animatable.
     public var path: C4Path? {
@@ -133,6 +178,9 @@ public class C4Shape: C4View {
         }
         set(color) {
             shapeLayer.fillColor = color?.CGColor
+            if color != nil {
+                gradientFill = nil
+            }
         }
     }
 

C4/UI/C4ShapeLayer.swift

@@ -81,6 +81,11 @@ public class C4ShapeLayer: CAShapeLayer {
             animation.configureOptions()
             animation.fromValue = self.lineDashPhase
             return animation;
+        } else if key == "contents" {
+            let animation = CABasicAnimation(keyPath: key)
+            animation.configureOptions()
+            animation.fromValue = self.contents
+            return animation;
         }
 
         return super.actionForKey(key)