如何获取UIImage中像素的颜色

Question

所以我正在尝试制作一个程序，在这个程序中我拍照，它"告诉"用户颜色是什么。我在实现func-getPixelColor部分时遇到了问题。有人能给我一些关于如何将这个程序融合在一起的提示吗？

import UIKit
class ViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
@IBOutlet weak var cameraButton: UIButton!
@IBOutlet weak var cameraView: UIImageView!
@IBOutlet weak var photosButton: UIButton!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
@IBAction func tappedCameraButton(_ sender: Any) {
let picker = UIImagePickerController()
picker.sourceType = .camera
picker.allowsEditing = true
picker.delegate = self
present(picker, animated: true)
}
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {

cameraView?.image = info[UIImagePickerController.InfoKey.editedImage] as? UIImage
picker.dismiss(animated: true, completion: nil)
}
extension UIImage {
func getPixelColor(pos: CGPoint) -> UIColor {
let pixelData = self.cgImage!.dataProvider!.data
let data: UnsafePointer<UInt8> = CFDataGetBytePtr(pixelData)
let pixelInfo: Int = ((Int(self.size.width) * Int(pos.y)) + Int(pos.x)) * 4
let r = CGFloat(data[pixelInfo]) / CGFloat(255.0)
let g = CGFloat(data[pixelInfo+1]) / CGFloat(255.0)
let b = CGFloat(data[pixelInfo+2]) / CGFloat(255.0)
let a = CGFloat(data[pixelInfo+3]) / CGFloat(255.0)
return UIColor(red: r, green: g, blue: b, alpha: a)
}
}
}

}

Answer 1

您需要获取用户触摸的CGPoint，然后使用getPixelColor(pos:)来获取颜色。

有两种方法可以获得CGPoint

1. 您可以使用任何方法来获取位置触摸Began(_：with：(、触摸Moved、触摸Ended

2. 使用敲击手势

这是StackOverlow代码，用于获取CGPoint：如何从抽头位置获取CGPoint？

Answer 2

extension UIImage {
func getPixelColor(pos: CGPoint) -> UIColor? {

guard let cgImg = cgImage, let provider = cgImg.dataProvider else {
return nil
}
let pixelData = provider.data

let data: UnsafePointer<UInt8> = CFDataGetBytePtr(pixelData)
let pixelInfo: Int = ((Int(self.size.width) * Int(pos.y)) + Int(pos.x)) * 4
let r = CGFloat(data[pixelInfo]) / CGFloat(255.0)
let g = CGFloat(data[pixelInfo+1]) / CGFloat(255.0)
let b = CGFloat(data[pixelInfo+2]) / CGFloat(255.0)
let a = CGFloat(data[pixelInfo+3]) / CGFloat(255.0)
return UIColor(red: r, green: g, blue: b, alpha: a)
}
}