[Swift] 画像の特定のピクセルの色を調べる ref: http://qiita.com/ohkawa/items/71db370b5a6b75bae517

UIImage+PixelColor.swift

import UIKit

let pixelDataByteSize = 4

extension UIImage {

    func getColor(pos: CGPoint) -> UIColor {

        let imageData = CGDataProviderCopyData(CGImageGetDataProvider(self.CGImage))
        let data : UnsafePointer = CFDataGetBytePtr(imageData)
        let scale = UIScreen.mainScreen().scale
        let address : Int = ((Int(self.size.width) * Int(pos.y * scale)) + Int(pos.x * scale)) * pixelDataByteSize
        let r = CGFloat(data[address])
        let g = CGFloat(data[address+1])
        let b = CGFloat(data[address+2])
        let a = CGFloat(data[address+3])

        return UIColor(red: r, green: g, blue: b, alpha: a)
    }
}

Useage.swift

let image = UIImage(named: "myImage")
let pixelColor = image!.getColor(CGPointMake(100, 100))

License is Completely Free
You can use this in any case without copyright notice.

In Swift 4.x:

fileprivate let pixelDataByteSize = 4

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

        guard let imageData = cgImage?.dataProvider?.data else { return nil }
        
        let data : UnsafePointer = CFDataGetBytePtr(imageData)
        let scale = UIScreen.main.scale
        let address : Int = ((Int(size.width) * Int(pos.y * scale)) + Int(pos.x * scale)) * pixelDataByteSize
        let r = CGFloat(data[address])
        let g = CGFloat(data[address+1])
        let b = CGFloat(data[address+2])
        let a = CGFloat(data[address+3])

        return UIColor(red: r, green: g, blue: b, alpha: a)
    }
}

Thanks!