ios - Swift 函数代码求讲解每句的意思

Question

func coloredImage(image: UIImage, red: CGFloat, green: CGFloat, blue: CGFloat, alpha: CGFloat) -> UIImage! {
    let rect = CGRect(origin: CGPointZero, size: image.size)
    UIGraphicsBeginImageContextWithOptions(image.size, false, image.scale)
    let context = UIGraphicsGetCurrentContext()
    image.drawInRect(rect)
    CGContextSetRGBFillColor(context, red, green, blue, alpha)
    CGContextSetBlendMode(context, CGBlendMode.SourceAtop)
    CGContextFillRect(context, rect)
    let result = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return result
}

主要是不太明白这些UI和CG函数的意思，求大神讲解下

Answer 1

雷雷

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Answer 2

這種問題自己查函數手冊就好了
UI開頭的內容是來自UIKit庫這是iOS控制項庫UIKit库 这是iOS控件库
CG开头是来自 Core GraphicCG開頭是來自Core Graphic庫這是2D繪圖庫