Implemented part c of task 11 (closes #11)

Author: Peter Vanhoef

Calculator/Calculator/Base.lproj/Main.storyboard

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="12120" systemVersion="16E195" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" colorMatched="YES" initialViewController="fcY-c8-IEH">
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="12120" systemVersion="16F73" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" colorMatched="YES" initialViewController="fcY-c8-IEH">
     <device id="retina4_7" orientation="portrait">
         <adaptation id="fullscreen"/>
     </device>
@@ -77,7 +77,7 @@
                                                     <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="FnA-Yx-lDt">
                                                         <rect key="frame" x="0.0" y="0.0" width="53" height="96"/>
                                                         <color key="backgroundColor" white="0.66666666666666663" alpha="1" colorSpace="calibratedWhite"/>
-                                                        <fontDescription key="fontDescription" type="system" pointSize="25"/>
+                                                        <fontDescription key="fontDescription" type="system" pointSize="23"/>
                                                         <state key="normal" title="→M">
                                                             <color key="titleColor" white="0.0" alpha="1" colorSpace="calibratedWhite"/>
                                                         </state>
@@ -132,7 +132,7 @@
                                                     <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="dtK-K0-MGK">
                                                         <rect key="frame" x="290" y="0.0" width="53" height="96"/>
                                                         <color key="backgroundColor" red="1" green="1" blue="1" alpha="1" colorSpace="calibratedRGB"/>
-                                                        <fontDescription key="fontDescription" type="system" pointSize="15"/>
+                                                        <fontDescription key="fontDescription" type="system" pointSize="14"/>
                                                         <state key="normal" title="Graph">
                                                             <color key="titleColor" red="1" green="0.0" blue="0.0" alpha="1" colorSpace="calibratedRGB"/>
                                                         </state>
@@ -148,7 +148,7 @@
                                                     <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="tLe-zK-OUJ">
                                                         <rect key="frame" x="0.0" y="0.0" width="53" height="95.5"/>
                                                         <color key="backgroundColor" white="0.66666666666666663" alpha="1" colorSpace="calibratedWhite"/>
-                                                        <fontDescription key="fontDescription" type="system" pointSize="25"/>
+                                                        <fontDescription key="fontDescription" type="system" pointSize="24"/>
                                                         <state key="normal" title="cos">
                                                             <color key="titleColor" white="0.0" alpha="1" colorSpace="calibratedWhite"/>
                                                         </state>
@@ -528,6 +528,6 @@
         </scene>
     </scenes>
     <inferredMetricsTieBreakers>
-        <segue reference="jyr-Pc-8eS"/>
+        <segue reference="Zbq-q6-BA9"/>
     </inferredMetricsTieBreakers>
 </document>

Calculator/Calculator/GraphingView.swift

@@ -44,12 +44,21 @@ class GraphingView: UIView {
         }
     }
 
+    func setOrigin(byReactingTo tapRecognizer: UITapGestureRecognizer) {
+        switch tapRecognizer.state {
+        case .changed, .ended:
+            origin = tapRecognizer.location(in: self)
+        default:
+            break
+        }
+    }
+    
     private var axesDrawer = AxesDrawer(color: UIColor.black, contentScaleFactor: 1.0)
 
     private func pathForUnaryFunction() -> UIBezierPath {
         let path = UIBezierPath()
 
-        if dataSource != nil {
+        if dataSource != nil && origin != nil {
             // iterate over every pixel of the width of the view
             let numberOfPixelsHorizontally = Int(bounds.size.width * contentScaleFactor)
             var firstPixel = true

Calculator/Calculator/GraphingViewController.swift

@@ -21,17 +21,6 @@ class GraphingViewController: UIViewController, GraphingViewDataSource {
         // Dispose of any resources that can be recreated.
     }
 
-
-    /*
-    // MARK: - Navigation
-
-    // In a storyboard-based application, you will often want to do a little preparation before navigation
-    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
-        // Get the new view controller using segue.destinationViewController.
-        // Pass the selected object to the new view controller.
-    }
-    */
-    
     @IBOutlet weak var graphingView: GraphingView! {
         didSet {
             graphingView.dataSource = self
@@ -41,6 +30,10 @@ class GraphingViewController: UIViewController, GraphingViewDataSource {
 
             let panRecognizer = UIPanGestureRecognizer(target: graphingView, action: #selector(graphingView.moveOrigin(byReactingTo:)))
             graphingView.addGestureRecognizer(panRecognizer)
+            
+            let tapRecognizer = UITapGestureRecognizer(target: graphingView, action: #selector(graphingView.setOrigin(byReactingTo:)))
+            tapRecognizer.numberOfTapsRequired = 2
+            graphingView.addGestureRecognizer(tapRecognizer)
         }
     }