资产目录中的景观与肖像背景图像 [英] Landscape vs. Portrait background image in Asset Catalog

问题描述

我有一个似乎陷入资产目录和大小类之间裂缝的用例。我的通用应用程序需要一个横向和纵向方向不同的全屏幕背景图像，而且仅支持iPad和iPad的横向图像。 iPhone 6。

I have a use case that seems to fall into the cracks between asset catalogs and size classes. My Universal app needs a full screen background image that is different in Landscape and Portrait orientations, and Landscape is only supported for the iPad & iPhone 6.

由于我无法将景观图像添加到新图像集的资产目录中，因此我目前的解决方案如下所示（支持iOS 7和8） ：

Since I can't add landscape images to the asset catalog for a new image set, my current solution looks like this (supports iOS 7 & 8):

// permit landscape mode only for iPads & iPhone 6 (would prefer to use size classes, but...?)
override func shouldAutorotate() -> Bool {
    let size = view.frame.size
    let maxv = max(size.width, size.height)
    return ((maxv > 700.0) || (maxv == 512.0)) ? true : false
}

// this will be triggered only for iOS 7, as long as viewWillTransitionToSize:withTransitionCoordinator: is also implemented!
override func willRotateToInterfaceOrientation(toInterfaceOrientation: UIInterfaceOrientation, duration: NSTimeInterval) {
    adjustToOrientation(toInterfaceOrientation)
}

// this will be triggered only for iOS 8
override func viewWillTransitionToSize(size: CGSize, withTransitionCoordinator coordinator: UIViewControllerTransitionCoordinator) {

    let orientation = UIApplication.sharedApplication().statusBarOrientation

    // need to reverse the sense of the orientation here; Application still has the previous orientation
    switch orientation {
        case .Portrait, .PortraitUpsideDown:
            adjustToOrientation(.LandscapeLeft)
        case .LandscapeLeft, .LandscapeRight:
            adjustToOrientation(.Portrait)
        default:
            adjustToOrientation(.Portrait)
    }

}

func adjustToOrientation(newInterfaceOrientation: UIInterfaceOrientation) {

    let size = view.frame.size

    // rotation already permitted only for iPad & iPhone 6, but need to know which one (size classes useless here?)
    switch (max(size.width, size.height)) {
        case 1024.0:
            if UIInterfaceOrientationIsLandscape(newInterfaceOrientation) {
                backgroundImage.image = UIImage(named: "Background-Landscape@2x~ipad.png")
            } else {
                backgroundImage.image = UIImage(named: "Background@2x~ipad.png")
            }
        case 736.0:
            if UIInterfaceOrientationIsLandscape(newInterfaceOrientation) {
                backgroundImage.image = UIImage(named: "Background-Landscape@3x~iphone.png")
            } else {
                backgroundImage.image = UIImage(named: "Background@3x~iphone.png")
            }
        case 512.0:
            if UIInterfaceOrientationIsLandscape(newInterfaceOrientation) {
                backgroundImage.image = UIImage(named: "Background-Landscape~ipad.png")
            } else {
                backgroundImage.image = UIImage(named: "Background~ipad.png")
            }
        default:
            break
    }

}

这有效，但似乎很脆弱。在实际处于横向模式之前，是否有更正确的方法将设备识别为支持横向中常规尺寸类的设备？或者某种方式，我错过了为图像集指定景观等价物？

This works, but seems fragile. Is there a more correct way to identify the device as something that supports a regular size class in Landscape, before actually being in Landscape mode? Or some way that I've missed to specify the Landscape equivalents for an image set?

推荐答案

所以最终的解决方案是：

So the final solution was:

- 将图像资源上的Width属性设置为Any + Regular，并为iPhone 6+和iPad添加几个Landscape图像，UIImage自动完成其余的

-Set the Width property on the image asset to Any+Regular and added a couple of Landscape images for the iPhone 6+ and iPad, and UIImage automatically does the rest

- 一种更优雅的方式，只允许这两个设备轮换，iOS 7和iOS 8：

-A more elegant way to permit rotation only for those two devices, in both iOS 7 & iOS 8:

override func shouldAutorotate() -> Bool {
    let scale = UIScreen.mainScreen().scale
    let idiom = UIDevice.currentDevice().userInterfaceIdiom
    return ((idiom == .Pad) || (scale > 2.0)) ? true : false
}

所以上面所有这些都是5行代码！

So all of the above down to 5 lines of code!

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