reworked SourcePreprocessor

Sources/Preprocessors/SourcePreprocessor.swift

@@ -32,28 +32,45 @@ class SourcePreprocessor: MotionPreprocessor {
     /// A reference to a MotionContext.
     weak var context: MotionContext!
 
-func process(fromViews: [UIView], toViews: [UIView]) {
+    /**
+     Processes the transitionary views.
+     - Parameter fromViews: An Array of UIViews.
+     - Parameter toViews: An Array of UIViews.
+     */
+    func process(fromViews: [UIView], toViews: [UIView]) {
         for fv in fromViews {
-      guard let id = context[fv]?.motionIdentifier,
-            let tv = context.destinationView(for: id) else { continue }
-      prepareFor(view: fv, targetView: tv)
+            guard let i = context[fv]?.motionIdentifier, let tv = context.destinationView(for: i) else {
+                continue
+            }
+            
+            prepare(view: fv, for: tv)
         }
+        
         for tv in toViews {
-      guard let id = context[tv]?.motionIdentifier,
-            let fv = context.sourceView(for: id) else { continue }
-      prepareFor(view: tv, targetView: fv)
+            guard let i = context[tv]?.motionIdentifier, let fv = context.sourceView(for: i) else {
+                continue
+            }
+            
+            prepare(view: tv, for: fv)
         }
     }
 
-  func prepareFor(view: UIView, targetView: UIView) {
+    /**
+     Prepares a given view for a target view.
+     - Parameter view: A UIView.
+     - Parameter for targetView: A UIView.
+     */
+    func prepare(view: UIView, for targetView: UIView) {
         let targetPos = context.container.convert(targetView.layer.position, from: targetView.superview!)
-
         var state = context[view]!
 
-    // use global coordinate space since over target position is converted from the global container
+        /**
+         Use global coordinate space since over target position is 
+         converted from the global container
+         */
         state.coordinateSpace = .global
 
-    // remove incompatible options
+        // Remove incompatible options.
         state.position = targetPos
         state.transform = nil
         state.size = nil
@@ -62,30 +79,39 @@ func process(fromViews: [UIView], toViews: [UIView]) {
         if view.bounds.size != targetView.bounds.size {
             state.size = targetView.bounds.size
         }
+
         if view.layer.cornerRadius != targetView.layer.cornerRadius {
             state.cornerRadius = targetView.layer.cornerRadius
         }
+        
         if view.layer.transform != targetView.layer.transform {
             state.transform = targetView.layer.transform
         }
+        
         if view.layer.shadowColor != targetView.layer.shadowColor {
             state.shadowColor = targetView.layer.shadowColor
         }
+        
         if view.layer.shadowOpacity != targetView.layer.shadowOpacity {
             state.shadowOpacity = targetView.layer.shadowOpacity
         }
+        
         if view.layer.shadowOffset != targetView.layer.shadowOffset {
             state.shadowOffset = targetView.layer.shadowOffset
         }
+        
         if view.layer.shadowRadius != targetView.layer.shadowRadius {
             state.shadowRadius = targetView.layer.shadowRadius
         }
+        
         if view.layer.shadowPath != targetView.layer.shadowPath {
             state.shadowPath = targetView.layer.shadowPath
         }
+        
         if view.layer.contentsRect != targetView.layer.contentsRect {
             state.contentsRect = targetView.layer.contentsRect
         }
+        
         if view.layer.contentsScale != targetView.layer.contentsScale {
             state.contentsScale = targetView.layer.contentsScale
         }