Determine if a CGImage is completely white

CGImage+Utilities.swift

import UIKit

extension CGImage {
    var isBlank: Bool {
        guard let data = dataProvider?.data, let buffer = CFDataGetBytePtr(data) else { return false }
        let length = CFDataGetLength(data)
        var i = 0
        while i < length {
            if buffer[i] < 255, buffer[i + 1] < 255, buffer[i + 2] < 255 {
                return false
            }
            i += 4
        }
        return true
    }
}

// Usage:
let img = #imageLiteral(resourceName: "MyImage")
img.cgImage?.isBlank // return true or false depending if it is all white or not