weak -> unowned (#3039)

* weak -> unowned

`ViewPortJob`s are owned by the Charts that make them. They are guaranteed to only exist while the chart exists. The `Transformer` and `ViewPortHandler` are supplied by the chart, so they will also only exist while the chart exists. Therefor none of them need to be `weak`, but can be `unowned` instead. It's a minor change in the code base (removing some guard statements), but it makes it much easier to discern how the framework is architected.

* pulled latest master

Source/Charts/Jobs/AnimatedMoveViewJob.swift

@@ -20,12 +20,6 @@ open class AnimatedMoveViewJob: AnimatedViewPortJob
 {
     internal override func animationUpdate()
     {
-        guard
-            let viewPortHandler = viewPortHandler,
-            let transformer = transformer,
-            let view = view
-            else { return }
-
         var pt = CGPoint(
             x: xOrigin + (CGFloat(xValue) - xOrigin) * phase,
             y: yOrigin + (CGFloat(yValue) - yOrigin) * phase

Source/Charts/Jobs/AnimatedViewPortJob.swift

@@ -40,16 +40,16 @@ open class AnimatedViewPortJob: ViewPortJob
         duration: TimeInterval,
         easing: ChartEasingFunctionBlock?)
     {
+        self.xOrigin = xOrigin
+        self.yOrigin = yOrigin
+        self._duration = duration
+        self._easing = easing
+
         super.init(viewPortHandler: viewPortHandler,
             xValue: xValue,
             yValue: yValue,
             transformer: transformer,
             view: view)
-
-        self.xOrigin = xOrigin
-        self.yOrigin = yOrigin
-        self._duration = duration
-        self._easing = easing
     }
 
     deinit

Source/Charts/Jobs/AnimatedZoomViewJob.swift

@@ -14,7 +14,7 @@ import CoreGraphics
 
 open class AnimatedZoomViewJob: AnimatedViewPortJob
 {
-    internal var yAxis: YAxis?
+    internal var yAxis: YAxis
     internal var xAxisRange: Double = 0.0
     internal var scaleX: CGFloat = 0.0
     internal var scaleY: CGFloat = 0.0
@@ -40,6 +40,15 @@ open class AnimatedZoomViewJob: AnimatedViewPortJob
         duration: TimeInterval,
         easing: ChartEasingFunctionBlock?)
     {
+        self.yAxis = yAxis
+        self.xAxisRange = xAxisRange
+        self.scaleX = scaleX
+        self.scaleY = scaleY
+        self.zoomCenterX = zoomCenterX
+        self.zoomCenterY = zoomCenterY
+        self.zoomOriginX = zoomOriginX
+        self.zoomOriginY = zoomOriginY
+
         super.init(viewPortHandler: viewPortHandler,
             xValue: 0.0,
             yValue: 0.0,
@@ -49,32 +58,17 @@ open class AnimatedZoomViewJob: AnimatedViewPortJob
             yOrigin: yOrigin,
             duration: duration,
             easing: easing)
-
-        self.yAxis = yAxis
-        self.xAxisRange = xAxisRange
-        self.scaleX = scaleX
-        self.scaleY = scaleY
-        self.zoomCenterX = zoomCenterX
-        self.zoomCenterY = zoomCenterY
-        self.zoomOriginX = zoomOriginX
-        self.zoomOriginY = zoomOriginY
     }
 
     internal override func animationUpdate()
     {
-        guard
-            let viewPortHandler = viewPortHandler,
-            let transformer = transformer,
-            let view = view
-            else { return }
-
         let scaleX = xOrigin + (self.scaleX - xOrigin) * phase
         let scaleY = yOrigin + (self.scaleY - yOrigin) * phase
 
         var matrix = viewPortHandler.setZoom(scaleX: scaleX, scaleY: scaleY)
         viewPortHandler.refresh(newMatrix: matrix, chart: view, invalidate: false)
 
-        let valsInView = CGFloat(yAxis?.axisRange ?? 0.0) / viewPortHandler.scaleY
+        let valsInView = CGFloat(yAxis.axisRange) / viewPortHandler.scaleY
         let xsInView = CGFloat(xAxisRange) / viewPortHandler.scaleX
 
         var pt = CGPoint(
@@ -91,6 +85,6 @@ open class AnimatedZoomViewJob: AnimatedViewPortJob
     internal override func animationEnd()
     {
         (view as? BarLineChartViewBase)?.calculateOffsets()
-        view?.setNeedsDisplay()
+        view.setNeedsDisplay()
     }
 }

Source/Charts/Jobs/MoveViewJob.swift

@@ -18,15 +18,9 @@ import CoreGraphics
 
 @objc(MoveChartViewJob)
 open class MoveViewJob: ViewPortJob
-{    
+{
     open override func doJob()
     {
-        guard
-            let viewPortHandler = viewPortHandler,
-            let transformer = transformer,
-            let view = view
-            else { return }
-
         var pt = CGPoint(
             x: xValue,
             y: yValue

Source/Charts/Jobs/ViewPortJob.swift

@@ -16,27 +16,27 @@ import CoreGraphics
 @objc(ChartViewPortJob)
 open class ViewPortJob: NSObject
 {
-    internal var point: CGPoint = CGPoint()
-    internal weak var viewPortHandler: ViewPortHandler?
-    internal var xValue: Double = 0.0
-    internal var yValue: Double = 0.0
-    internal weak var transformer: Transformer?
-    internal weak var view: ChartViewBase?
-    
+    internal var point: CGPoint = .zero
+    internal unowned var viewPortHandler: ViewPortHandler
+    internal var xValue = 0.0
+    internal var yValue = 0.0
+    internal unowned var transformer: Transformer
+    internal unowned var view: ChartViewBase
+
     @objc public init(
         viewPortHandler: ViewPortHandler,
         xValue: Double,
         yValue: Double,
         transformer: Transformer,
         view: ChartViewBase)
     {
-        super.init()
-
         self.viewPortHandler = viewPortHandler
         self.xValue = xValue
         self.yValue = yValue
         self.transformer = transformer
         self.view = view
+
+        super.init()
     }
 
     @objc open func doJob()

Source/Charts/Jobs/ZoomViewJob.swift

@@ -22,7 +22,7 @@ open class ZoomViewJob: ViewPortJob
     internal var scaleX: CGFloat = 0.0
     internal var scaleY: CGFloat = 0.0
     internal var axisDependency: YAxis.AxisDependency = .left
-    
+
     @objc public init(
         viewPortHandler: ViewPortHandler,
         scaleX: CGFloat,
@@ -33,26 +33,21 @@ open class ZoomViewJob: ViewPortJob
         axis: YAxis.AxisDependency,
         view: ChartViewBase)
     {
+        self.scaleX = scaleX
+        self.scaleY = scaleY
+        self.axisDependency = axis
+
         super.init(
             viewPortHandler: viewPortHandler,
             xValue: xValue,
             yValue: yValue,
             transformer: transformer,
             view: view)
-
-        self.scaleX = scaleX
-        self.scaleY = scaleY
-        self.axisDependency = axis
+
     }
 
     open override func doJob()
     {
-        guard
-            let viewPortHandler = viewPortHandler,
-            let transformer = transformer,
-            let view = view
-            else { return }
-
         var matrix = viewPortHandler.setZoom(scaleX: scaleX, scaleY: scaleY)
         viewPortHandler.refresh(newMatrix: matrix, chart: view, invalidate: false)