Change color of certain pixels(outlined with bezierpath) in a UIImage

Question

I have displayed an image with 50% alpha in UIImageview. My requirement is to highlight(alpha 100%) some parts(outlined with bezierpath) of UIImage. Here are steps I tried.

1. drawing image in UIGraphicsGetCurrentContext
2. outlining the desired parts using bezier path.
3. extract new image using this code- let newImage = UIGraphicsGetImageFromCurrentImageContext

I tried process the newImage using below code -

`func processPixelsInImage(_ image: UIImage) -> UIImage? { guard let inputCGImage = image.cgImage else { //print("unable to get cgImage") return nil } let colorSpace = CGColorSpaceCreateDeviceRGB() let width = inputCGImage.width let height = inputCGImage.height let bytesPerPixel = 4 let bitsPerComponent = 8 let bytesPerRow = bytesPerPixel * width let bitmapInfo = RGBA32.bitmapInfo

    guard let context = CGContext(data: nil, width: width, height: height, bitsPerComponent: bitsPerComponent, bytesPerRow: bytesPerRow, space: colorSpace, bitmapInfo: bitmapInfo) else {
        //print("unable to create context")
        return nil
    }
    context.draw(inputCGImage, in: CGRect(x: 0, y: 0, width: width, height: height))

    guard let buffer = context.data else {
        //print("unable to get context data")
        return nil
    }

    let pixelBuffer = buffer.bindMemory(to: RGBA32.self, capacity: width * height)

    //let white = RGBA32(red: 255, green: 255, blue: 255, alpha: 255)
    //let clear = RGBA32(red: 0, green: 0, blue: 0, alpha: 1)

    for row in 0 ..< Int(height) {
        for column in 0 ..< Int(width) {
            let offset = row * width + column
            let color = image.getPixelColor(pos: CGPoint(x: row, y: column))
            
            let newpixelcolor = RGBA32(red: UInt8(color.0 * 255), green: UInt8(color.1 * 255), blue: UInt8(color.2 * 255), alpha: 1)
            
            for path in bezierPathArray {
                if path.contains(CGPoint(x: row, y: column)) {
                    pixelBuffer[offset] = newpixelcolor//color.withAlphaComponent(1.0)
                }
            }
        }
    }

    let outputCGImage = context.makeImage()!
    let outputImage = UIImage(cgImage: outputCGImage, scale: image.scale, orientation: image.imageOrientation)

    return outputImage
}`

Problem with above code - consuming 100% CPU, too much memory (50 mb for 760*1280 image).

I am thinking to process the pixels using Metal framework(utilising GPU instead of CPU)

How I can do it? Pls help. Any help would be highly appreciated