swift - 参数标签与任何可用的重载 swift 不匹配

Question

我有一个在图像上绘制文本的函数，但问题是当我调用这个函数时它给出了一个错误“参数标签'(_:, _:)'不匹配任何可用的重载” 我是 swift 的新手，不知道如何修复

func write_text_on_image(drawtext text:NSString , inimage img : UIImage , atpoint point : CGPoint) -> UIImage {

        let textcolor = UIColor.white
        let font = UIFont(name: "Helvetica", size: 16)

        let scale = UIScreen.main.scale
        UIGraphicsBeginImageContextWithOptions(img.size, false, scale)

        let font_attributes = [

            kCTFontAttributeName : font,
            kCTForegroundColorAttributeName : textcolor
        ]

      img.draw(in: CGRect(origin: CGPoint.zero, size: img.size))

        let rect = CGRect(origin: point, size: img.size)

        text.draw(in: rect, withAttributes: font_attributes as [NSAttributedString.Key : Any])

        let newimg = UIGraphicsGetImageFromCurrentImageContext()

        UIGraphicsEndPDFContext()

        return newimg!

    }

我称这个函数为

write_text_on_image(drawtext: "THis is some text", inimage: UIImage(named: "test.png")!, atpoint: CGPoint(20,20))[!

check out screen of function [] 1

Answer 1

正如@vadian 所说，代码补全会对您有所帮助。这是我在 Playground 中复制片段得到的结果:

func write_text_on_image(drawtext text:NSString , inimage img : UIImage , atpoint point : CGPoint) -> UIImage { return UIImage() }

write_text_on_image(drawtext: "NSString", inimage: UIImage(), atpoint: CGPoint(x: 0, y: 0))

不执行任何操作，但会编译。