在Interface Builder(XCode 4)中设置UIButton拉伸背景图像

import UIKit

class InterfaceBuilderViewController: UIViewController {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let button = UIButton(type: .system)
        button.setTitle("Sample Button", for: .normal)
        if let sampleImage = UIImage(named: "sampleImage") {
            button.setImage(sampleImage, for: .normal)
        }
        
        button.frame = CGRect(x: 50, y: 50, width: 200, height: 40)
        view.addSubview(button)
    }
}

import UIKit

class InterfaceBuilderViewController: UIViewController {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let button = UIButton(type: .system)
        button.setTitle("Sample Button", for: .normal)
        if let sampleImage = UIImage(named: "sampleImage") {
            button.setImage(sampleImage, for: .normal)
            
            // 设置拉伸区域
            button.imageEdgeInsets = UIEdgeInsets(top: 0, left: -100, bottom: 0, right: 0)
            
            button.frame = CGRect(x: 50, y: 50, width: 200, height: 40)
            view.addSubview(button)
        }
    }
}

button.imageEdgeInsets = UIEdgeInsets(top: 0, left: -100, bottom: 0, right: 0)

button.setTitleColor(.white, for: .normal)
button.setTitle("Sample Button", for: .normal)
button.setTitleFont(UIFont.systemFont(ofSize: 17), for: .normal)
button.layer.cornerRadius = 5.0
button.layer.borderColor = UIColor.blue.cgColor
button.layer.borderWidth = 1.0