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modified scanning area logic to support non centered images
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@aslanyanhaik
aslanyanhaik committed May 6, 2020
1 parent cbeea6e commit 255195d
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Showing 4 changed files with 76 additions and 80 deletions.
2 changes: 1 addition & 1 deletion Sources/Internal/RCConstants.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -28,5 +28,5 @@ 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 = (0...180)
static let pixelThreshold = (UInt8(0)...UInt8(180))
}
127 changes: 66 additions & 61 deletions Sources/Internal/RCImageDecoder.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -27,37 +27,17 @@ 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
}
}

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 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 { RCConstants.pixelThreshold.contains(Int(data[Int($0.x), Int($0.y)])) ? RCBit.one : RCBit.zero }
let bits = locations.map { RCConstants.pixelThreshold.contains(data[Int($0.x), Int($0.y)]) ? RCBit.one : RCBit.zero }
return bits
}

Expand All @@ -72,47 +52,67 @@ 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: RCConstants.pixelThreshold.contains(Int(data[region.x, region.y])) ? RCBit.one : RCBit.zero, 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 = RCConstants.pixelThreshold.contains(Int(data[coordinate.x, coordinate.y])) ? RCBit.one : RCBit.zero
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.init(bit: RCConstants.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 = RCConstants.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 = RCConstants.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 }
Expand Down Expand Up @@ -164,7 +164,7 @@ extension RCImageDecoder {
}
}.first!
}

private func calculateTransform(from points: [CGPoint]) -> CATransform3D {
let perspective = RCTransformation(points)
let middleRect = CGRect(origin: .zero, size: CGSize(width: CGFloat(size), height: CGFloat(size)))
Expand Down Expand Up @@ -215,6 +215,11 @@ extension RCImageDecoder {
case right
}

enum ScanMode {
case horizontal
case vertical
}

final class PixelContainer {
let rows: Int
var columns: Int { data.count / rows }
Expand Down
8 changes: 0 additions & 8 deletions Sources/Public/RCCameraViewController.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -113,7 +113,6 @@ public extension RCCameraViewController {
super.viewDidLayoutSubviews()
configureMaskLayer()
videoPreviewLayer?.frame = view.bounds
calculateScanArea()
}
}

Expand Down Expand Up @@ -157,7 +156,6 @@ 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)
Expand All @@ -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)
Expand Down
19 changes: 9 additions & 10 deletions Sources/Public/RCCoder.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -44,7 +44,6 @@ 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)
Expand All @@ -55,15 +54,15 @@ public extension RCCoder {
configuration.validate(text)
}

func validateForBlackBackground(colors: [UIColor]) -> Bool {
colors.allSatisfy { color in
var white: CGFloat = 0
var alpha: CGFloat = 0
guard color.getWhite(&white, alpha: &alpha) else { return false }
guard alpha == 1.0 else { return false }
return RCConstants.pixelThreshold.contains(Int(white * 255))
}
}
// func validateForBlackBackground(colors: [UIColor]) -> Bool {
// colors.allSatisfy { color in
// var white: CGFloat = 0
// var alpha: CGFloat = 0
// guard color.getWhite(&white, alpha: &alpha) else { return false }
// guard alpha == 1.0 else { return false }
// return RCConstants.pixelThreshold.contains(Int(white * 255))
// }
// }
}

extension RCCoder {
Expand Down

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