ios - 如何在快速更改屏幕方向时避免背景图像平铺

Question

我正在制作一个简单的单页 ios 应用程序的原型(prototype)。当设备方向从纵向切换到横向时，我试图让背景在两个图像之间交换。 '''

override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {

    UIGraphicsBeginImageContext(self.view.frame.size)

    switch UIDevice.current.orientation{
    case .portrait:
        UIImage(named: "img_001")?.draw(in: self.view.bounds)
    case .portraitUpsideDown:
        UIImage(named: "img_001")?.draw(in: self.view.bounds)
    case .landscapeLeft:
        UIImage(named: "img_002")?.draw(in: self.view.bounds)
    case .landscapeRight:
        UIImage(named: "img_002")?.draw(in: self.view.bounds)
    default:
        break
    }

    let image: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
    UIGraphicsEndImageContext()
    self.view.backgroundColor = UIColor(patternImage: image)

}

'''

当设备翻转时背景会发生变化，但图像平铺在显示屏上，而它需要是填充屏幕的单个图像。

Answer 1

稍微更新了您的代码以使用正确的“大小”和“边界”

UIGraphicsBeginImageContext(size)
    var bounds = self.view.bounds
    bounds.size = size

    switch UIDevice.current.orientation{
    case .portrait:
        UIImage(named: "download.jpg")?.draw(in: bounds)
    case .portraitUpsideDown:
        UIImage(named: "download.jpg")?.draw(in: bounds)
    case .landscapeLeft:
        UIImage(named: "download.jpg")?.draw(in: bounds)
    case .landscapeRight:
        UIImage(named: "download.jpg")?.draw(in: bounds)
    default:
        break
    }

    let image: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
    UIGraphicsEndImageContext()
    self.view.backgroundColor = UIColor(patternImage: image)

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