Add option to animate the slider's scale to give a visual indication during the pan gesture when adjusting its value

Author: daprice

TactileSlider/Classes/TactileSlider.swift

@@ -57,8 +57,13 @@ import UIKit
 	}
 
 	@IBInspectable open var isContinuous: Bool = true
+	
+	// If true, a single tap anywhere in the slider will set it to that value
 	@IBInspectable open var enableTapping: Bool = true
 
+	// If true, the slider will animate its scale when it is being dragged
+	@IBInspectable open var scaleUpWhenInUse: Bool = false
+	
 	@IBInspectable open var trackBackground: UIColor = UIColor.darkGray {
 		didSet {
 			renderer.trackBackground = trackBackground
@@ -205,6 +210,12 @@ import UIKit
 			if isContinuous || sender.state == .ended || sender.state == .cancelled {
 				sendActions(for: .valueChanged)
 			}
+			
+			if sender.state != .ended && sender.state != .cancelled {
+				renderer.popUp = scaleUpWhenInUse
+			} else {
+				renderer.popUp = false
+			}
 		}
 	}
 

TactileSlider/Classes/TactileSliderLayerRenderer.swift

@@ -35,6 +35,14 @@ internal class TactileSliderLayerRenderer {
 		}
 	}
 
+	var popUp: Bool = false {
+		didSet(oldValue) {
+			if oldValue != popUp {
+				updatePopUp()
+			}
+		}
+	}
+	
 	let trackLayer = CALayer()
 	let thumbLayer = CAShapeLayer()
 	let maskLayer = CAShapeLayer()
@@ -73,6 +81,21 @@ internal class TactileSliderLayerRenderer {
 		trackLayer.opacity = alpha
 	}
 
+	private func updatePopUp() {
+		CATransaction.begin()
+		CATransaction.setDisableActions(true)
+		
+		let zPosition: CGFloat = popUp ? 1.025 : 1
+		trackLayer.transform = CATransform3DScale(CATransform3DIdentity, zPosition, zPosition, zPosition)
+		
+		let animation = CABasicAnimation(keyPath: "transform.scale")
+		animation.timingFunction = CAMediaTimingFunction(name: CAMediaTimingFunctionName.easeOut)
+		animation.duration = 0.1
+		trackLayer.add(animation, forKey: nil)
+		
+		CATransaction.commit()
+	}
+	
 	internal func updateBounds(_ bounds: CGRect) {
 		CATransaction.begin()
 		CATransaction.setDisableActions(true)