如何在uiimage中找到特定颜色并更改颜色

import UIKit

func changeColorInImage(image: UIImage, targetColor: UIColor, newColor: UIColor) -> UIImage? {
    // 1. 将UIImage转换为CGImage
    guard let cgImage = image.cgImage else {
        return nil
    }
    
    // 2. 创建一个位图上下文
    let width = cgImage.width
    let height = cgImage.height
    let colorSpace = CGColorSpaceCreateDeviceRGB()
    let bytesPerPixel = 4
    let bytesPerRow = bytesPerPixel * width
    let bitsPerComponent = 8
    let bitmapInfo = CGImageAlphaInfo.premultipliedLast.rawValue | CGBitmapInfo.byteOrder32Big.rawValue
    guard let context = CGContext(data: nil, width: width, height: height, bitsPerComponent: bitsPerComponent, bytesPerRow: bytesPerRow, space: colorSpace, bitmapInfo: bitmapInfo) else {
        return nil
    }
    
    // 3. 绘制图像到位图上下文
    let rect = CGRect(x: 0, y: 0, width: width, height: height)
    context.draw(cgImage, in: rect)
    
    // 4. 获取位图数据
    guard let data = context.data else {
        return nil
    }
    
    let buffer = data.bindMemory(to: UInt32.self, capacity: width * height)
    
    // 5. 遍历位图数据并修改颜色
    let targetComponents = targetColor.cgColor.components!
    let newComponents = newColor.cgColor.components!
    
    for i in 0..<(width * height) {
        let pixel = buffer[i]
        let red = CGFloat((pixel >> 16) & 0xff) / 255.0
        let green = CGFloat((pixel >> 8) & 0xff) / 255.0
        let blue = CGFloat(pixel & 0xff) / 255.0
        
        if red == targetComponents[0] && green == targetComponents[1] && blue == targetComponents[2] {
            let newRed = UInt32(newComponents[0] * 255.0) << 16
            let newGreen = UInt32(newComponents[1] * 255.0) << 8
            let newBlue = UInt32(newComponents[2] * 255.0)
            let newPixel = newRed | newGreen | newBlue
            
            buffer[i] = newPixel
        }
    }
    
    // 6. 创建新的UIImage
    if let newCGImage = context.makeImage() {
        let newImage = UIImage(cgImage: newCGImage)
        return newImage
    }
    
    return nil
}

// 使用示例
let originalImage = UIImage(named: "original_image")
let targetColor = UIColor.red
let newColor = UIColor.blue

if let modifiedImage = changeColorInImage(image: originalImage, targetColor: targetColor, newColor: newColor) {
    // 处理修改后的图像
} else {
    // 修改颜色失败
}