如何在iOS中更改图像的RGB值？

// 加载图像
let originalImage = UIImage(named: "image.jpg")

// 创建图形上下文
UIGraphicsBeginImageContextWithOptions(originalImage.size, false, 0.0)
let context = UIGraphicsGetCurrentContext()

// 将原始图像绘制到图形上下文中
originalImage.draw(in: CGRect(x: 0, y: 0, width: originalImage.size.width, height: originalImage.size.height))

// 获取图像数据
let data = context!.data
let dataPointer = data?.assumingMemoryBound(to: UInt8.self)

// 修改图像数据的RGB值
let bytesPerPixel = 4
let bytesPerRow = bytesPerPixel * Int(originalImage.size.width)
let imageHeight = Int(originalImage.size.height)

for y in 0..<imageHeight {
    let rowStart = y * bytesPerRow
    for x in 0..<bytesPerRow {
        let pixelIndex = rowStart + x
        let redIndex = pixelIndex + 0
        let greenIndex = pixelIndex + 1
        let blueIndex = pixelIndex + 2
        
        // 增加红色通道值
        dataPointer?[redIndex] = min(dataPointer?[redIndex] ?? 0 + 50, 255)
    }
}

// 将修改后的图像数据绘制回图形上下文中
context?.draw(context!.makeImage()!, in: CGRect(x: 0, y: 0, width: originalImage.size.width, height: originalImage.size.height))

// 获取修改后的图像
let modifiedImage = UIGraphicsGetImageFromCurrentImageContext()

// 结束图形上下文
UIGraphicsEndImageContext()