Update README.md

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Example/Example.xcodeproj/project.pbxproj

@@ -17,7 +17,7 @@
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
-		22C936CC2447221100128DE6 /* Example.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = Example.app; sourceTree = BUILT_PRODUCTS_DIR; };
+		22C936CC2447221100128DE6 /* Round Code.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = "Round Code.app"; sourceTree = BUILT_PRODUCTS_DIR; };
 		22C936CF2447221100128DE6 /* AppDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppDelegate.swift; sourceTree = "<group>"; };
 		22C936D12447221100128DE6 /* SceneDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SceneDelegate.swift; sourceTree = "<group>"; };
 		22C936D32447221100128DE6 /* ViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ViewController.swift; sourceTree = "<group>"; };
@@ -51,7 +51,7 @@
 		22C936CD2447221100128DE6 /* Products */ = {
 			isa = PBXGroup;
 			children = (
-				22C936CC2447221100128DE6 /* Example.app */,
+				22C936CC2447221100128DE6 /* Round Code.app */,
 			);
 			name = Products;
 			sourceTree = "<group>";
@@ -97,7 +97,7 @@
 				22C936E42447225600128DE6 /* RoundCode */,
 			);
 			productName = Example;
-			productReference = 22C936CC2447221100128DE6 /* Example.app */;
+			productReference = 22C936CC2447221100128DE6 /* Round Code.app */;
 			productType = "com.apple.product-type.application";
 		};
 /* End PBXNativeTarget section */
@@ -306,7 +306,7 @@
 					"@executable_path/Frameworks",
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = com.roundcode.example;
-				PRODUCT_NAME = "$(TARGET_NAME)";
+				PRODUCT_NAME = "Round Code";
 				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
@@ -325,7 +325,7 @@
 					"@executable_path/Frameworks",
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = com.roundcode.example;
-				PRODUCT_NAME = "$(TARGET_NAME)";
+				PRODUCT_NAME = "Round Code";
 				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};

Example/Example/Base.lproj/Main.storyboard

@@ -7,10 +7,10 @@
         <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
     </dependencies>
     <scenes>
-        <!--Round Code-->
+        <!--View Controller-->
         <scene sceneID="a2g-4i-pyL">
             <objects>
-                <viewController id="0zP-ee-W0J" customClass="ViewController" customModule="Example" customModuleProvider="target" sceneMemberID="viewController">
+                <viewController id="0zP-ee-W0J" customClass="ViewController" customModule="Round_Code" customModuleProvider="target" sceneMemberID="viewController">
                     <view key="view" contentMode="scaleToFill" id="Rvj-Nv-Ukh">
                         <rect key="frame" x="0.0" y="0.0" width="414" height="896"/>
                         <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
@@ -23,11 +23,9 @@
                             </imageView>
                             <textField opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="left" contentVerticalAlignment="center" borderStyle="roundedRect" placeholder="Message" minimumFontSize="17" clearButtonMode="always" translatesAutoresizingMaskIntoConstraints="NO" id="KyC-Sh-W2M">
                                 <rect key="frame" x="5" y="503" width="404" height="27"/>
-                                <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                                 <constraints>
                                     <constraint firstAttribute="height" constant="27" id="BZz-IP-j2V"/>
                                 </constraints>
-                                <color key="textColor" white="0.0" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                                 <fontDescription key="fontDescription" type="system" pointSize="14"/>
                                 <textInputTraits key="textInputTraits" autocorrectionType="no" spellCheckingType="no"/>
                                 <connections>
@@ -45,7 +43,7 @@
                                 <rect key="frame" x="20" y="93" width="374" height="32"/>
                                 <segments>
                                     <segment title="Orange"/>
-                                    <segment title="Magenta"/>
+                                    <segment title="Red"/>
                                     <segment title="Green"/>
                                     <segment title="Brown"/>
                                     <segment title="Cyan"/>
@@ -56,13 +54,13 @@
                             </segmentedControl>
                             <label hidden="YES" opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="" textAlignment="center" lineBreakMode="tailTruncation" numberOfLines="0" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="pan-9N-son">
                                 <rect key="frame" x="0.0" y="88" width="414" height="774"/>
-                                <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
+                                <color key="backgroundColor" systemColor="systemBackgroundColor" cocoaTouchSystemColor="whiteColor"/>
                                 <fontDescription key="fontDescription" type="system" pointSize="32"/>
                                 <nil key="textColor"/>
                                 <nil key="highlightedColor"/>
                             </label>
                         </subviews>
-                        <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
+                        <color key="backgroundColor" systemColor="systemBackgroundColor" cocoaTouchSystemColor="whiteColor"/>
                         <constraints>
                             <constraint firstItem="aXm-cj-1eD" firstAttribute="trailing" secondItem="zZa-y7-66Y" secondAttribute="trailing" constant="20" id="5cA-OR-hh7"/>
                             <constraint firstItem="akC-qR-hPk" firstAttribute="width" secondItem="IDN-sg-2ib" secondAttribute="width" id="603-Vl-61F"/>
@@ -85,17 +83,31 @@
                         </constraints>
                         <viewLayoutGuide key="safeArea" id="aXm-cj-1eD"/>
                     </view>
-                    <navigationItem key="navigationItem" title="Round Code" id="XgG-ZM-i9d">
-                        <barButtonItem key="leftBarButtonItem" title="Share" id="so2-d3-VCF">
-                            <connections>
-                                <action selector="share:" destination="0zP-ee-W0J" id="uNU-bV-PaS"/>
-                            </connections>
-                        </barButtonItem>
-                        <barButtonItem key="rightBarButtonItem" title="Camera" id="Ckh-RB-Kad">
-                            <connections>
-                                <action selector="scan:" destination="0zP-ee-W0J" id="h78-sA-B0C"/>
-                            </connections>
-                        </barButtonItem>
+                    <navigationItem key="navigationItem" id="XgG-ZM-i9d">
+                        <leftBarButtonItems>
+                            <barButtonItem title="Share" id="so2-d3-VCF">
+                                <connections>
+                                    <action selector="share:" destination="0zP-ee-W0J" id="uNU-bV-PaS"/>
+                                </connections>
+                            </barButtonItem>
+                            <barButtonItem title="Config" id="33c-Ng-bhx">
+                                <connections>
+                                    <action selector="changeConfig:" destination="0zP-ee-W0J" id="izA-qU-8it"/>
+                                </connections>
+                            </barButtonItem>
+                        </leftBarButtonItems>
+                        <rightBarButtonItems>
+                            <barButtonItem title="Camera" id="Ckh-RB-Kad">
+                                <connections>
+                                    <action selector="scan:" destination="0zP-ee-W0J" id="h78-sA-B0C"/>
+                                </connections>
+                            </barButtonItem>
+                            <barButtonItem title="Image" id="rwW-La-cl3">
+                                <connections>
+                                    <action selector="scanImage:" destination="0zP-ee-W0J" id="Cdh-9Q-DD2"/>
+                                </connections>
+                            </barButtonItem>
+                        </rightBarButtonItems>
                     </navigationItem>
                     <connections>
                         <outlet property="imageView" destination="IDN-sg-2ib" id="V1v-sS-seZ"/>

Example/Example/Info.plist

@@ -22,6 +22,8 @@
 	<true/>
 	<key>NSAppleMusicUsageDescription</key>
 	<string>To scan roundcodes</string>
+	<key>NSPhotoLibraryAddUsageDescription</key>
+	<string>To save RoundCode images</string>
 	<key>NSCameraUsageDescription</key>
 	<string>To scan roundcodes</string>
 	<key>UIApplicationSceneManifest</key>
@@ -62,5 +64,7 @@
 		<string>UIInterfaceOrientationLandscapeLeft</string>
 		<string>UIInterfaceOrientationLandscapeRight</string>
 	</array>
+	<key>UIUserInterfaceStyle</key>
+	<string>Light</string>
 </dict>
 </plist>

Example/Example/ViewController.swift

@@ -30,21 +30,60 @@ class ViewController: UIViewController {
   @IBOutlet weak var messageLabel: UILabel!
   var coder = RCCoder()
   var image = RCImage(message: "")
-  let colors: [[UIColor]] = [[.orange, .gray], [.orange, .magenta], [.systemGreen, .systemBlue], [.orange, .brown], [.purple, .cyan]]
-
+  let colors: [[UIColor]] = [[.orange, .magenta], [.systemPink, .systemTeal], [.systemTeal, .systemGreen], [.orange, .brown], [.purple, .cyan]]
+  var isScanningFromLibrary = false
 }
 
 extension ViewController {
   
+  @IBAction func changeConfig(_ sender: Any) {
+    textField.text = ""
+    image.message = ""
+    imageView.image = try? coder.encode(image)
+    let vc = UIAlertController(title: "Select Configuration", message: nil, preferredStyle: .actionSheet)
+    let uuidAction = UIAlertAction(title: "UUID", style: .default) { _ in
+      self.coder = RCCoder(configuration: .uuidConfiguration)
+    }
+    let numericAction = UIAlertAction(title: "Numeric", style: .default) { _ in
+      self.coder = RCCoder(configuration: .numericConfiguration)
+    }
+    let shortAction = UIAlertAction(title: "Short", style: .default) { _ in
+      self.coder = RCCoder(configuration: .shortConfiguration)
+    }
+    let defaultAction = UIAlertAction(title: "Default", style: .default) { _ in
+      self.coder = RCCoder(configuration: .defaultConfiguration)
+    }
+    let cancelAction = UIAlertAction(title: "Cancel", style: .cancel)
+    vc.addAction(uuidAction)
+    vc.addAction(numericAction)
+    vc.addAction(shortAction)
+    vc.addAction(defaultAction)
+    vc.addAction(cancelAction)
+    present(vc, animated: true)
+  }
+  
+  
+  @IBAction func scanImage(_ sender: Any) {
+    isScanningFromLibrary = true
+    let vc = UIImagePickerController()
+    vc.sourceType = .photoLibrary
+    vc.allowsEditing = true
+    vc.delegate = self
+    present(vc, animated: true)
+  }
+  
+  
   @IBAction func scan(_ sender: Any) {
     let vc = RCCameraViewController()
+    coder.scanningMode  = .lightBackground
+    vc.coder = coder
     vc.delegate = self
     present(vc, animated: true)
   }
   
   @IBAction func share(_ sender: Any) {
     image.size = 1000
-    image.contentInsets = UIEdgeInsets(top: 100, left: 100, bottom: 100, right: 100)
+    image.contentInsets = UIEdgeInsets(top: 50, left: 50, bottom: 50, right: 50)
     let uiImage = try? coder.encode(image)
     image.size = 300
     image.contentInsets = UIEdgeInsets(top: 8, left: 8, bottom: 8, right: 8)
@@ -87,8 +126,24 @@ extension ViewController: UINavigationControllerDelegate, UIImagePickerControlle
   
   func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
     let camImage = info[.editedImage] as! UIImage
-    image.attachmentImage = camImage
-    imageView.image = try? coder.encode(image)
+    if isScanningFromLibrary {
+      if let message = try? coder.decode(camImage) {
+        messageLabel.text = message
+        messageLabel.isHidden = false
+        DispatchQueue.main.asyncAfter(deadline: .now() + 3) {
+          self.messageLabel.isHidden = true
+        }
+      }
+    } else {
+      image.attachmentImage = camImage
+      imageView.image = try? coder.encode(image)
+    }
+    isScanningFromLibrary = false
+    picker.dismiss(animated: true)
+  }
+  
+  func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
+    isScanningFromLibrary = false
     picker.dismiss(animated: true)
   }
 }

README.md

@@ -5,10 +5,8 @@
 [![Twitter: @aslanyanhaik](https://img.shields.io/badge/Contact-Twitter-blue.svg?style=flat)](https://twitter.com/aslanyanhaik)
 
 
-
-RoundCode is a Facebook messenger like custom QR code with lots of customization. 
-
-In addition to encoder the RoundCode also includes convenient camera scanner and decoder.
+RoundCode is custom circular QR code with lots of customization. 
+Similar to Facebook messenger and Apple's App Clip Codes the RoundCode includes convenient camera scanner and decoder.
 
 <h3 align="center">
 <img src="appearance.png" alt="Different styles of RoundCode for iOS"/>
@@ -81,14 +79,14 @@ You can also decode a UIImage like this
 
 ```swift
 let coder = RCCoder()
-  do {
-    messageLabel.text = try coder.decode(UIImage(named: code)!)
-  } catch {
-    //handle errors
-  }
+do {
+  messageLabel.text = try coder.decode(UIImage(named: code)!)
+} catch {
+  //handle errors
+}
 ```
 
-### Appearance
+## Appearance
 
 You can change the appearance like this
 
@@ -100,10 +98,14 @@ image.size = 300
 image.gradientType = .linear(angle: CGFloat.pi)
 image.tintColors = [.red, .black]
 ```
+If image is on dark background you should change scanning mode to `darkBackground`
 
-⚠️ When choosing colors or transparent background you should keep in mind that decoder will detect the code on light background with dark colors ⚠️
+```swift
+let coder = RCCoder()
+coder.scanningMode = .darkBackground
+```
 
-### Advanced
+## Advanced coding configuration
 
 You can provide custom coding configuration in order to encode long text by reducing number of characters
 

RoundCode.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name             = 'RoundCode'
-  s.version          = '1.0.1'
+  s.version          = '1.3.0'
   s.summary          = 'Facebook messenger style custom barcode.'
   s.description      = <<-DESC
                      Encode and decode data into custom stylish barcode.

Sources/Internal/RCBitCoder.swift

@@ -70,7 +70,6 @@ extension RCBitCoder {
   
   
   func decode(_ bits: [RCBit]) throws -> String {
-    guard bits.contains(.one) else { return "" }
     //starting character to bits
     var startingIndexCharacter = String(repeating: "0", count: configuration.bitesPerSymbol)
     startingIndexCharacter += String(configuration.characters.firstIndex(of: configuration.version.startingCharacter)!, radix: 2)

Sources/Internal/RCConstants.swift

@@ -28,5 +28,6 @@ struct RCConstants {
   static let dotSizeScale: CGFloat = 0.08
   static let dotPatterns: [CGFloat] = [6, 4, 2]
   static let dotPointRange = (Float(1.3)...Float(2.5))
-  static let pixelThreshold = 180
+  static let lightBackgroundRange = UInt8(0)...UInt8(180)
+  static let darkBackgroundRange = UInt8(100)...UInt8(255)
 }

Sources/Internal/RCImageDecoder.swift

@@ -27,41 +27,24 @@ struct RCImageDecoder {
   internal let configuration: RCCoderConfiguration
   internal var size = 720
   internal var bytesPerRow = 720
-  internal var padding = 0
-  private var sectionSize: Int {
-    self.size / 5
-  }
+  internal var pixelThreshold = RCConstants.lightBackgroundRange
 }
 
 extension RCImageDecoder {
   func process(pointer: UnsafeMutablePointer<UInt8>) throws -> [RCBit] {
     let bufferData = UnsafeMutableBufferPointer<UInt8>(start: pointer, count: size * bytesPerRow)
     let data = PixelContainer(rows: bytesPerRow, items: bufferData)
-    var points = [CGPoint]()
-    for side in Side.allCases {
-      switch side {
-        case .left:
-          let point = try scanControlPoint(for: data, region: (padding, (size - sectionSize) / 2), side: side)
-          points.append(point)
-        case .top:
-          let point = try scanControlPoint(for: data, region: ((size - sectionSize) / 2, padding), side: side)
-          points.append(point)
-        case .right:
-          let point = try scanControlPoint(for: data, region: (size - sectionSize - padding, (size - sectionSize) / 2), side: side)
-          points.append(point)
-        case .bottom:
-          let point = try scanControlPoint(for: data, region: ((size - sectionSize) / 2, size - sectionSize - padding), side: side)
-          points.append(point)
-      }
-    }
-    let image = try fixPerspective(pointer, points: points)
-    let bits = decode(image)
+    let points = try scanControlPoints(for: data)
+    let transform = calculateTransform(from: points)
+    let mapper = RCPointMapper(transform: transform, size: size)
+    let locations = mapper.map(points: calculateBitLocations())
+    let bits = locations.map { pixelThreshold.contains(data[Int($0.x), Int($0.y)]) ? RCBit.one : RCBit.zero }
     return bits
   }
   
   func decode(_ image: UIImage) throws -> [RCBit] {
     let pixelData = UnsafeMutableRawPointer.allocate(byteCount: size * size, alignment: MemoryLayout<UInt8>.alignment)
-    let context = generateContext(data: pixelData, size: size, bytesPerRow: self.bytesPerRow)
+    let context = CGContext(data: pixelData, width: size, height: size, bitsPerComponent: 8, bytesPerRow: bytesPerRow, space: CGColorSpaceCreateDeviceGray(), bitmapInfo: CGImageAlphaInfo.none.rawValue)
     context?.draw(image.cgImage!, in: CGRect(origin: .zero, size: CGSize(width: size, height: size)))
     let bits = try process(pointer: pixelData.assumingMemoryBound(to: UInt8.self))
     pixelData.deallocate()
@@ -70,47 +53,66 @@ extension RCImageDecoder {
 }
 
 extension RCImageDecoder {
-  private func scanControlPoint(for data: PixelContainer, region: (x: Int, y: Int), side: Side) throws -> CGPoint {
-    
-    func scan(region: (x: Int, y: Int, size: Int), data: PixelContainer, coordinate: (Int) -> (x: Int, y: Int), comparison: (PixelPattern, (x: Int, y: Int)) -> Bool) -> [PixelPattern] {
-      var lastPattern = PixelPattern(bit: data[region.x, region.y] > RCConstants.pixelThreshold ? RCBit.zero : RCBit.one, x: region.x, y: region.y, count: 0)
-      var pixelPatterns = [lastPattern]
-      var count = 0
-      let maxSize = region.size * region.size
-      while count < maxSize {
-        let coordinate = coordinate(count)
-        let bit = data[coordinate.x, coordinate.y] > RCConstants.pixelThreshold ? RCBit.zero : RCBit.one
-        if comparison(lastPattern, coordinate), lastPattern.bit == bit {
-          lastPattern.count += 1
-          pixelPatterns[pixelPatterns.count - 1] = lastPattern
-        } else {
-          lastPattern = PixelPattern(bit: bit, x: coordinate.x, y: coordinate.y, count: 1)
-          pixelPatterns.append(lastPattern)
-        }
-        count += 1
+  private func scanControlPoints(for data: PixelContainer) throws -> [CGPoint] {
+    var horizontalPatterns = [PixelPattern]()
+    var verticalPatterns = [PixelPattern]()
+    var points = [CGPoint]()
+    for side in Side.allCases {
+      switch side {
+        case .left:
+          horizontalPatterns = scanPixelPattern(for: .horizontal, data: data)
+          points.append(try controlPoint(for: horizontalPatterns, side: side))
+        case .right:
+          points.append(try controlPoint(for: horizontalPatterns, side: side))
+        case .top:
+          verticalPatterns = scanPixelPattern(for: .vertical, data: data)
+          points.append(try controlPoint(for: verticalPatterns, side: side))
+        case .bottom:
+          points.append(try controlPoint(for: verticalPatterns, side: side))
       }
-      return pixelPatterns
     }
-    
-    let pixelPatterns: [PixelPattern]
-    switch side {
-      case .left, .right:
-        pixelPatterns = scan(region: (region.x, region.y, sectionSize), data: data, coordinate: { count in
-          let x = count % sectionSize + region.x
-          let y = count / sectionSize + region.y
-          return (x, y)
-        }, comparison: { (pattern, coordinate) in
-          return pattern.y == coordinate.y
-        })
-      case .top, .bottom:
-        pixelPatterns = scan(region: (region.x, region.y, sectionSize), data: data, coordinate: { count in
-          let x = count / sectionSize + region.x
-          let y = count % sectionSize + region.y
-          return (x, y)
-        }, comparison: { (pattern, coordinate) in
-          return pattern.x == coordinate.x
-        })
+    return points
+  }
+
+  private func scanPixelPattern(for mode: ScanMode, data: PixelContainer) -> [PixelPattern] {
+    var lastPattern = PixelPattern(bit: pixelThreshold.contains((data[0, 0])) ? RCBit.one : RCBit.zero, x: 0, y: 0, count: 0)
+    var pixelPatterns = [lastPattern]
+    var count = 0
+    let maxSize = size * size
+    switch mode {
+      case .horizontal:
+        while count < maxSize {
+          let x = count % size
+          let y = count / size
+          let bit = pixelThreshold.contains(data[x, y]) ? RCBit.one : RCBit.zero
+          if lastPattern.y == y, lastPattern.bit == bit {
+            lastPattern.count += 1
+            pixelPatterns[pixelPatterns.count - 1] = lastPattern
+          } else {
+            lastPattern = PixelPattern(bit: bit, x: x, y: y, count: 1)
+            pixelPatterns.append(lastPattern)
+          }
+          count += 1
+      }
+      case .vertical:
+        while count < maxSize {
+          let x = count / size
+          let y = count % size
+          let bit = pixelThreshold.contains(data[x, y]) ? RCBit.one : RCBit.zero
+          if lastPattern.x == x, lastPattern.bit == bit {
+            lastPattern.count += 1
+            pixelPatterns[pixelPatterns.count - 1] = lastPattern
+          } else {
+            lastPattern = PixelPattern(bit: bit, x: x, y: y, count: 1)
+            pixelPatterns.append(lastPattern)
+          }
+          count += 1
+      }
     }
+    return pixelPatterns
+  }
+  
+  private func controlPoint(for pixelPatterns: [PixelPattern], side: Side) throws -> CGPoint {
     let controlPoints = try pixelPatterns.withUnsafeBufferPointer { (pixelPatternsBuffer) -> [CGPoint] in
       var points = [CGPoint]()
       guard pixelPatternsBuffer.count >= 5 else { throw RCError.decoding }
@@ -162,43 +164,22 @@ extension RCImageDecoder {
       }
     }.first!
   }
-  
-  private func fixPerspective(_ data: UnsafeMutablePointer<UInt8>, points: [CGPoint]) throws -> CGImage {
-    guard let context = generateContext(data: data, size: size, bytesPerRow: bytesPerRow), let cgImage = context.makeImage() else {
-      throw RCError.decoding
-    }
-    let image = UIGraphicsImageRenderer(size: CGSize(width: CGFloat(size), height: CGFloat(size))).image { context in
-      let baseView = UIView(frame: context.format.bounds)
-      let imageView = UIImageView(frame: context.format.bounds)
-      baseView.addSubview(imageView)
-      imageView.image = UIImage(cgImage: cgImage)
-      imageView.layer.anchorPoint = .zero
-      imageView.layer.frame = context.format.bounds
-      let perspective = RCTransformation(points)
-      let destination = RCTransformation([CGPoint(x: context.format.bounds.minX, y: context.format.bounds.midY),
-                                          CGPoint(x: context.format.bounds.midX, y: context.format.bounds.minY),
-                                          CGPoint(x: context.format.bounds.midX, y: context.format.bounds.maxY),
-                                          CGPoint(x: context.format.bounds.maxX, y: context.format.bounds.midY)])
-      let transform = perspective.perspectiveTransform(to: destination)
-      imageView.transform3D = transform
-      baseView.drawHierarchy(in: context.format.bounds, afterScreenUpdates: true)
-    }
-    guard let renderImage = image.cgImage else {
-      throw RCError.decoding
-    }
-    return renderImage
+    
+  private func calculateTransform(from points: [CGPoint]) -> CATransform3D {
+    let perspective = RCTransformation(points)
+    let middleRect = CGRect(origin: .zero, size: CGSize(width: CGFloat(size), height: CGFloat(size)))
+    let destination = RCTransformation([CGPoint(x: middleRect.minX, y: middleRect.midY),
+                                        CGPoint(x: middleRect.midX, y: middleRect.minY),
+                                        CGPoint(x: middleRect.midX, y: middleRect.maxY),
+                                        CGPoint(x: middleRect.maxX, y: middleRect.midY)])
+    return perspective.perspectiveTransform(to: destination)
   }
   
-  private func decode(_ image: CGImage) -> [RCBit] {
-    let pixelData = UnsafeMutableRawPointer.allocate(byteCount: image.width * image.height, alignment: MemoryLayout<UInt8>.alignment)
-    let context = generateContext(data: pixelData, size: image.width, bytesPerRow: image.width)
-    context?.draw(image, in: CGRect(origin: .zero, size: CGSize(width: image.width, height: image.height)))
-    let buffer = UnsafeMutableBufferPointer<UInt8>(start: pixelData.assumingMemoryBound(to: UInt8.self), count: image.width * image.height)
-    let data = PixelContainer(rows: image.height, items: buffer)
-    let size = CGFloat(data.columns)
-    let lineWidth = CGFloat(image.height) * RCConstants.dotSizeScale / 5 //number of lines including spaces
-    let mainRadius = CGFloat(image.height) / 2
-    let startAngle = asin(CGFloat(image.height) * RCConstants.dotSizeScale / mainRadius)
+  private func calculateBitLocations() -> [CGPoint] {
+    let size = CGFloat(self.size)
+    let lineWidth = size * RCConstants.dotSizeScale / 5 //number of lines including spaces
+    let mainRadius = size / 2
+    let startAngle = asin(size * RCConstants.dotSizeScale / mainRadius)
     var points = [CGPoint]()
     let center = CGPoint(x: size / 2, y: size / 2)
     (0...3).forEach { offset in
@@ -214,15 +195,7 @@ extension RCImageDecoder {
         }
       }
     }
-    let bits = points.map { data[Int($0.x), Int($0.y)] > RCConstants.pixelThreshold ? RCBit.zero : RCBit.one }
-    pixelData.deallocate()
-    return bits
-  }
-}
-
-extension RCImageDecoder {
-  private func generateContext(data: UnsafeMutableRawPointer?, size: Int, bytesPerRow: Int) -> CGContext? {
-    return  CGContext(data: data, width: size, height: size, bitsPerComponent: 8, bytesPerRow: bytesPerRow, space: CGColorSpaceCreateDeviceGray(), bitmapInfo: CGImageAlphaInfo.none.rawValue)
+    return points
   }
 }
 
@@ -242,6 +215,11 @@ extension RCImageDecoder {
     case right
   }
   
+  enum ScanMode {
+    case horizontal
+    case vertical
+  }
+  
   final class PixelContainer {
     let rows: Int
     var columns: Int { data.count / rows }

Sources/Internal/RCPointMapper.swift

@@ -0,0 +1,55 @@
+//  MIT License
+
+//  Copyright (c) 2020 Haik Aslanyan
+
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+
+import QuartzCore
+
+struct RCPointMapper {
+  
+  private var transform: CATransform3D
+  private let denominatorX: CGFloat
+  private let denominatorY: CGFloat
+  private let denominatorW: CGFloat
+  private let size: CGFloat
+  
+  init(transform: CATransform3D, size: Int) {
+    let translateDueToDisposition = CATransform3DMakeTranslation(-CGFloat(size) / 2, -CGFloat(size) / 2, 0)
+    self.transform = CATransform3DConcat(transform, translateDueToDisposition)
+    self.size = CGFloat(size)
+    self.denominatorX = transform.m12 * transform.m21 - transform.m11  * transform.m22 + transform.m14 * transform.m22 * transform.m41 - transform.m12 * transform.m24 * transform.m41 - transform.m14 * transform.m21 * transform.m42 + transform.m11 * transform.m24 * transform.m42
+    self.denominatorY = -transform.m12 * transform.m21 + transform.m11 * transform.m22 - transform.m14 * transform.m22 * transform.m41 + transform.m12 * transform.m24 * transform.m41 + transform.m14 * transform.m21 * transform.m42 - transform.m11 * transform.m24 * transform.m42
+    self.denominatorW = transform.m12 * transform.m21 - transform.m11 * transform.m22 + transform.m14 * transform.m22 * transform.m41 - transform.m12 * transform.m24 * transform.m41 - transform.m14 * transform.m21 * transform.m42 + transform.m11 * transform.m24 * transform.m42
+  }
+  
+  func map(points: [CGPoint]) -> [CGPoint] {
+    return points.map { point in
+      let modelPoint =  CGPoint(x: (point.x * 2.0 - size) / 2.0, y: (point.y * 2.0 - size) / 2.0)
+      let x = modelPoint.x
+      let y = modelPoint.y
+      let xp: CGFloat = (transform.m22 * transform.m41 - transform.m21 * transform.m42 - transform.m22 * x + transform.m24 * transform.m42 * x + transform.m21 * y - transform.m24 * transform.m41 * y) / denominatorX
+      let yp: CGFloat = (-transform.m11 * transform.m42 + transform.m12 * (transform.m41 - x) + transform.m14 * transform.m42 * x + transform.m11 * y - transform.m14 * transform.m41 * y) / denominatorY
+      let wp: CGFloat = (transform.m12 * transform.m21 - transform.m11 * transform.m22 + transform.m14 * transform.m22 * x - transform.m12 * transform.m24 * x - transform.m14 * transform.m21 * y + transform.m11 * transform.m24 * y) / denominatorW
+      let actualPoint = CGPoint(x: xp / wp, y: yp / wp)
+      let isOutOfBounds = !(0...size).contains(actualPoint.x) || !(0...size).contains(actualPoint.y)
+      return isOutOfBounds ? .zero : actualPoint
+    }
+  }
+}

Sources/Public/RCCameraViewController.swift

@@ -23,7 +23,7 @@
 import UIKit
 import AVFoundation
 
-public final class RCCameraViewController: UIViewController, UIImagePickerControllerDelegate {
+public final class RCCameraViewController: UIViewController {
   
   //MARK: Public properties
   public weak var delegate: RCCameraViewControllerDelegate?
@@ -113,7 +113,6 @@ public extension RCCameraViewController {
     super.viewDidLayoutSubviews()
     configureMaskLayer()
     videoPreviewLayer?.frame = view.bounds
-    calculateScanArea()
   }
 }
 
@@ -157,12 +156,11 @@ extension RCCameraViewController {
     guard let captureDevice = AVCaptureDevice.default(for: .video) else { return }
     do {
       captureSession.sessionPreset = .hd1280x720
-      calculateScanArea()
       let input = try AVCaptureDeviceInput(device: captureDevice)
       input.device.activeVideoMaxFrameDuration = CMTimeMake(value: 1, timescale: 30)
       captureSession.addInput(input)
       let videoOutput = AVCaptureVideoDataOutput()
-      videoOutput.setSampleBufferDelegate(self, queue: .main)
+      videoOutput.setSampleBufferDelegate(self, queue: DispatchQueue.global(qos: .userInteractive))
       videoOutput.videoSettings = [kCVPixelBufferPixelFormatTypeKey as String: NSNumber(value: kCVPixelFormatType_420YpCbCr8BiPlanarFullRange)]
       captureSession.addOutput(videoOutput)
     } catch {
@@ -170,12 +168,6 @@ extension RCCameraViewController {
     }
   }
   
-  private func calculateScanArea() {
-    let actualWidth = view.frame.height / 16 * 9
-    let sideArea = (actualWidth - view.frame.width * 0.9) / 2
-    coder.imageDecoder.padding = Int(sideArea / actualWidth * 720)
-  }
-  
   private func configureVideoPreview(orientation: AVCaptureVideoOrientation = .portrait) {
     videoPreviewLayer?.removeFromSuperlayer()
     videoPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
@@ -205,8 +197,10 @@ extension RCCameraViewController: AVCaptureVideoDataOutputSampleBufferDelegate {
     coder.imageDecoder.bytesPerRow = bytesPerRow
     if let message = try? coder.decode(buffer: lumaCopy.assumingMemoryBound(to: UInt8.self)) {
       captureSession.stopRunning()
-      delegate?.cameraViewController(didFinishScanning: message)
-      dismiss(animated: true)
+      DispatchQueue.main.async {[weak self] in
+        self?.delegate?.cameraViewController(didFinishScanning: message)
+        self?.dismiss(animated: true)
+      }
     }
     lumaCopy.deallocate()
     CVPixelBufferUnlockBaseAddress(pixelBuffer, .readOnly)

Sources/Public/RCCoder.swift

@@ -25,6 +25,11 @@ import UIKit
 public final class RCCoder {
   
   public let configuration: RCCoderConfiguration
+  public var scanningMode = ScanningMode.lightBackground {
+    didSet {
+      imageDecoder.pixelThreshold = scanningMode == .lightBackground ? RCConstants.lightBackgroundRange : RCConstants.darkBackgroundRange
+    }
+  }
   internal lazy var imageDecoder = RCImageDecoder(configuration: self.configuration)
   internal lazy var imageEncoder = RCImageEncoder(configuration: self.configuration)
   internal lazy var bitCoder = RCBitCoder(configuration: self.configuration)
@@ -44,7 +49,6 @@ public extension RCCoder {
   func decode(_ image: UIImage) throws -> String {
     guard image.size.width == image.size.height else { throw RCError.wrongImageSize }
     imageDecoder.size = image.cgImage!.height
-    imageDecoder.padding = 0
     imageDecoder.bytesPerRow = image.cgImage!.height
     let bits = try imageDecoder.decode(image)
     let message = try bitCoder.decode(bits)
@@ -56,6 +60,13 @@ public extension RCCoder {
   }
 }
 
+public extension RCCoder {
+  enum ScanningMode {
+    case lightBackground
+    case darkBackground
+  }
+}
+
 extension RCCoder {
   
   func decode(buffer: UnsafeMutablePointer<UInt8>) throws -> String {
@@ -64,3 +75,4 @@ extension RCCoder {
     return message
   }
 }
+

Sources/Public/RCCoderConfiguration.swift

@@ -24,13 +24,12 @@ import Foundation
 
 public struct RCCoderConfiguration {
   
-  public let version: Version
+  public let version = Version.v1
   public let maxMessageCount: Int
   public let bitesPerSymbol: Int
   public let characters: [Character]
   
-  public init(version: Version = .v1, characters: String) {
-    self.version = version
+  public init(characters: String) {
     var charactersArray = characters.map({$0})
     charactersArray.append(version.startingCharacter)
     charactersArray.append(contentsOf: version.emptyCharacters)