iOS | 如何快速获取运行时图像的宽度/高度

请尝试以下代码。它可以根据您对iPhone 6S设备的要求完美地工作。当设备屏幕方向更改为横向模式时，我正在计算标签框的x位置和宽度。对于其他设备（例如5S和4S），您需要根据设备的高宽比计算x的位置和宽度。例如，我使用了9和18之类的常数。如果要为不同的设备工作代码，则需要使用比率因子。希望对您有所帮助！

import UIKit

class ViewController: UIViewController {

@IBOutlet weak var theImageView: UIImageView!
@IBOutlet weak var theLabel: UILabel!

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    theLabel.frame.size.width = (theImageView.image?.size.width)!

    NSNotificationCenter.defaultCenter().addObserver(self, selector: "rotated", name: UIDeviceOrientationDidChangeNotification, object: nil)
}

override func viewDidAppear(animated: Bool) {

    if(UIDeviceOrientationIsLandscape(UIDevice.currentDevice().orientation))
    {
        if (theImageView.image?.size.height)! > (theImageView.image?.size.width)! {
            theLabel.frame.origin.x = (view.frame.size.width - (theImageView.image?.size.height)!)/2
            theLabel.frame.size.width = (theImageView.image?.size.height)!
        }
        else {
            theLabel.frame.origin.x = ((theImageView.image?.size.height)!/2) - 9
            theLabel.frame.size.width = rint(view.frame.size.width) - (theImageView.image?.size.height)! + 18
        }
    }

    if(UIDeviceOrientationIsPortrait(UIDevice.currentDevice().orientation))
    {
        theLabel.frame.size.width = theImageView.frame.size.width
    }
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

override func viewWillTransitionToSize(size: CGSize, withTransitionCoordinator coordinator: UIViewControllerTransitionCoordinator) {
    //theImageView.frame.size.width = (theImageView.image?.size.width)!
    //theImageView.frame.size.height = (theImageView.image?.size.height)!
}

func rotated()
{
    if(UIDeviceOrientationIsLandscape(UIDevice.currentDevice().orientation))
    {
        if (theImageView.image?.size.height)! > (theImageView.image?.size.width)! {
            theLabel.frame.origin.x = (view.frame.size.width - (theImageView.image?.size.height)!)/2
            theLabel.frame.size.width = (theImageView.image?.size.height)!
        }
        else {
            theLabel.frame.origin.x = ((theImageView.image?.size.height)!/2) - 9
            theLabel.frame.size.width = rint(view.frame.size.width) - (theImageView.image?.size.height)! + 18
        }
    }

    if(UIDeviceOrientationIsPortrait(UIDevice.currentDevice().orientation))
    {
        theLabel.frame.size.width = theImageView.frame.size.width
    }


}