Firebase ML Kit ile Görüntü Üzerindeki Metinlerin Tanınması | iOS --- http://www.bulentsiyah.com/firebase-ml-kit-ile-goruntu-uzerindeki-metinlerin-taninmasi-ios/

FirebaseMLMetinTanimaViewController.swift

//
//  FirebaseMLMetinTanimaViewController.swift
//  ML Ornekleri
//
//  Created by Bülent Siyah on 6.07.2018.
//  Copyright © 2018 Bülent Siyah. All rights reserved.
//

import UIKit
import FirebaseMLVision

class FirebaseMLMetinTanimaViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
    
    @IBOutlet weak var imageView: UIImageView!
    @IBOutlet weak var textResult: UITextView!
    
    var imagePicker: UIImagePickerController!
    var userPickedImage: UIImage?
    
    var textDetector: VisionTextDetector!
      var cloudTextDetector: VisionCloudTextDetector!
      var frameSublayer = CALayer()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        textDetector = Vision().textDetector()
        imageView.layer.addSublayer(frameSublayer)
        
        cloudTextDetector = Vision().cloudTextDetector()
        
        imagePicker = UIImagePickerController()
        imagePicker.delegate = self

    }

    
    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
        
        if let pickedImage = info[UIImagePickerControllerOriginalImage] as? UIImage {
            imageView.contentMode = .scaleAspectFit
            imageView.image = pickedImage
            self.userPickedImage = pickedImage
        }
        
        dismiss(animated: true, completion: nil)
    }
    
    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        dismiss(animated: true, completion: nil)
    }
    
    
    @IBAction func btnResimSec(_ sender: Any) {
        imagePicker.allowsEditing = false
        imagePicker.sourceType = .photoLibrary
        present(imagePicker, animated: true, completion: nil)
    }
    
    @IBAction func btnAnalizEt(_ sender: Any) {
  self.textResult.text = ""
        let visionImage = VisionImage(image: self.userPickedImage!)
            textDetector.detect(in: visionImage) { features, error in
                self.processResult(from: features, error: error)
            }
        
      //  runCloudTextRecognition(with: imageView.image!)
    }
    
    func processResult(from text: [VisionText]?, error: Error?) {
        removeFrames()
        guard let features = text, let image = imageView.image else {
            return
        }
        for text in features {
            if let block = text as? VisionTextBlock {
                for line in block.lines {
                       self.textResult.insertText("\n")
                    for element in line.elements {
                        self.textResult.insertText( element.text)
                        self.addFrameView(
                            featureFrame: element.frame,
                            imageSize: image.size,
                            viewFrame: self.imageView.frame,
                            text: element.text
                        )
                    }
                }
            }
        }
    }
    

    
    func runCloudTextRecognition(with image: UIImage) {
        let visionImage = VisionImage(image: image)
        cloudTextDetector.detect(in: visionImage) { features, error in
            if let error = error {
                print("Received error: \(error)")
                return
            }
            
            self.processCloudResult(from: features, error: error)
        }
    }
    
    
    func processCloudResult(from text: VisionCloudText?, error: Error?) {
        removeFrames()
        guard let features = text, let image = imageView.image, let pages = features.pages else {
            return
        }
        for page in pages {
            for block in page.blocks ?? []  {
                for paragraph in block.paragraphs ?? [] {
                    for word in paragraph.words ?? [] {
                        self.addFrameView(
                            featureFrame: word.frame,
                            imageSize: image.size,
                            viewFrame: self.imageView.frame
                        )
                    }
                }
            }
        }
    }

    
    private func removeFrames() {
        guard let sublayers = self.frameSublayer.sublayers else { return }
        for sublayer in sublayers {
            guard let frameLayer = sublayer as CALayer? else {
                print("Failed to remove frame layer.")
                continue
            }
            frameLayer.removeFromSuperlayer()
        }
    }
    
    /// Converts a feature frame to a frame UIView that is displayed over the image.
    ///
    /// - Parameters:
    ///   - featureFrame: The rect of the feature with the same scale as the original image.
    ///   - imageSize: The size of original image.
    ///   - viewRect: The view frame rect on the screen.
    private func addFrameView(featureFrame: CGRect, imageSize: CGSize, viewFrame: CGRect, text: String? = nil) {
        print("Frame: \(featureFrame).")
        
        let viewSize = viewFrame.size
        
        // Find resolution for the view and image
        let rView = viewSize.width / viewSize.height
        let rImage = imageSize.width / imageSize.height
        
        // Define scale based on comparing resolutions
        var scale: CGFloat
        if rView > rImage {
            scale = viewSize.height / imageSize.height
        } else {
            scale = viewSize.width / imageSize.width
        }
        
        // Calculate scaled feature frame size
        let featureWidthScaled = featureFrame.size.width * scale
        let featureHeightScaled = featureFrame.size.height * scale
        
        // Calculate scaled feature frame top-left point
        let imageWidthScaled = imageSize.width * scale
        let imageHeightScaled = imageSize.height * scale
        
        let imagePointXScaled = (viewSize.width - imageWidthScaled) / 2
        let imagePointYScaled = (viewSize.height - imageHeightScaled) / 2
        
        let featurePointXScaled = imagePointXScaled + featureFrame.origin.x * scale
        let featurePointYScaled = imagePointYScaled + featureFrame.origin.y * scale
        
        // Define a rect for scaled feature frame
        let featureRectScaled = CGRect(x: featurePointXScaled,
                                       y: featurePointYScaled,
                                       width: featureWidthScaled,
                                       height: featureHeightScaled)
        
        drawFrame(featureRectScaled, text: text)
    }
    
    
    /// Creates and draws a frame for the calculated rect as a sublayer.
    ///
    /// - Parameter rect: The rect to draw.
    private func drawFrame(_ rect: CGRect, text: String? = nil) {
        let bpath: UIBezierPath = UIBezierPath(rect: rect)
        let rectLayer: CAShapeLayer = CAShapeLayer()
        rectLayer.path = bpath.cgPath
        rectLayer.strokeColor = Constants.lineColor
        rectLayer.fillColor = Constants.fillColor
        rectLayer.lineWidth = Constants.lineWidth
        if let text = text {
            let textLayer = CATextLayer()
            textLayer.string = text
            textLayer.fontSize = 12.0
            textLayer.foregroundColor = Constants.lineColor
            let center = CGPoint(x: rect.midX, y: rect.midY)
            textLayer.position = center
            textLayer.frame = rect
            textLayer.alignmentMode = kCAAlignmentCenter
            textLayer.contentsScale = UIScreen.main.scale
            frameSublayer.addSublayer(textLayer)
        }
        frameSublayer.addSublayer(rectLayer)
    }
  
    fileprivate enum Constants {
        static let lineWidth: CGFloat = 3.0
        static let lineColor = UIColor.yellow.cgColor
        static let fillColor = UIColor.clear.cgColor
    }


}