如何调整大图像的大小并使它迅速适应UIButton？

Question

I am trying to place a large image on a button after resizing to the exact size of button. I am making use of this code

var FB = UIButton(type:UIButtonType.Custom) as UIButton
var image = UIImage(named: "facebook-logo-png-2.png")
func buttonTouchDown(sender:UIButton!){
    print("button Touch Down")
}

 override func viewDidLoad() {
    super.viewDidLoad()

  FB.frame = CGRectMake(0,0 , 100, 100)
    FB.backgroundColor = UIColor.clearColor()
    FB.addTarget(self, action: #selector(buttonTouchDown(_:)), forControlEvents: .TouchDown)
    FB.setImage(image, forState: .Normal)
    FB.imageEdgeInsets = UIEdgeInsetsMake(25,25,25,25)
    self.view.addSubview(FB)}

I am not getting the desired output. Currently, my output looks like this screen shot This is my first iOS app, please help me if possible

Thanks in advance

Answer 1

Use this line

FB.contentMode = .ScaleAspectFit

Before self.view.addSubview(FB)

What it does is scale the image to the fit the size while being true to the aspect ratio of the image being set.