获取CGImage Swift所有像素的RGBA值

import UIKit
import CoreGraphics

func getRGBAValues(from image: UIImage) -> [UInt8]? {
    guard let cgImage = image.cgImage else { return nil }
    
    let width = cgImage.width
    let height = cgImage.height
    let bytesPerPixel = 4
    let bytesPerRow = width * bytesPerPixel
    let colorSpace = CGColorSpaceCreateDeviceRGB()
    let context = CGContext(data: nil,
                            width: width,
                            height: height,
                            bitsPerComponent: 8,
                            bytesPerRow: bytesPerRow,
                            space: colorSpace,
                            bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue)
    
    context?.draw(cgImage, in: CGRect(x: 0, y: 0, width: width, height: height))
    
    guard let data = context?.data else { return nil }
    let pixels = data.bindMemory(to: UInt8.self, capacity: width * height * bytesPerPixel)
    
    var rgbaValues: [UInt8] = []
    for y in 0..<height {
        for x in 0..<width {
            let pixelIndex = (y * width + x) * bytesPerPixel
            let r = pixels[pixelIndex]
            let g = pixels[pixelIndex + 1]
            let b = pixels[pixelIndex + 2]
            let a = pixels[pixelIndex + 3]
            rgbaValues.append(r)
            rgbaValues.append(g)
            rgbaValues.append(b)
            rgbaValues.append(a)
        }
    }
    
    return rgbaValues
}

// 使用示例
if let image = UIImage(named: "exampleImage") {
    if let rgbaValues = getRGBAValues(from: image) {
        print("RGBA Values: \(rgbaValues)")
    } else {
        print("Failed to get RGBA values.")
    }
}