Swift重写UIButton的图片和标题的位置

import UIKit

class ResetBtn: UIButton {

    let IMAGE_RATIO :CGFloat = 0.7  // 图片占整个按钮高度的比例

    let TITLE_FONT:CGFloat = 13   // 设置按钮标题字体默认的大小
    override init(frame: CGRect) {

        super.init(frame: frame)

        self.setImageAndTitle()

    }

    required init?(coder aDecoder: NSCoder) {

        super.init(coder: aDecoder)

         self.setImageAndTitle()
    }

    func setImageAndTitle(){

        self.imageView?.contentMode = .Center   // 设置图片显示的模式  居中

        self.titleLabel?.textAlignment = .Center  // 文本文字居中显示

        self.titleLabel?.font = UIFont.systemFontOfSize(TITLE_FONT) //文本文字默认大小
        self.setTitleColor(UIColor.lightGrayColor(), forState: .Normal)  // 文本文字默认颜色

    }

 /// 重写highlighted 状态

    override var  highlighted : Bool {

            set{

            }
            get{

                return false
            }

    }

    override func imageRectForContentRect(contentRect: CGRect) -> CGRect {

        let imageX:CGFloat = 0
        let imageY:CGFloat = 0
        let imageW:CGFloat = self.frame.size.width
        let imageH:CGFloat = self.frame.size.height * IMAGE_RATIO

        return CGRectMake(imageX, imageY, imageW, imageH)

    }

    override func titleRectForContentRect(contentRect: CGRect) -> CGRect {

        let titleX:CGFloat = 0
        let titleY:CGFloat = self.frame.size.height * IMAGE_RATIO

        let titleW:CGFloat = self.frame.size.width
        let titleH:CGFloat = self.frame.size.height * (1.0 - IMAGE_RATIO)

        return CGRectMake(titleX, titleY, titleW, titleH)

    }

}