问题描述

我已经学会了如何使用仿射变换旋转视图(请参阅 用于子视图四周的间距约束.

@IBOutlet 弱变量 rightSpace: NSLayoutConstraint！@IBOutlet 弱变量 leftSpace:NSLayoutConstraint！@IBOutlet 弱 var topSpace:NSLayoutConstraint！@IBOutlet weak var bottomSpace: NSLayoutConstraint！

subview.transform = CGAffineTransformMakeRotation(CGFloat(M_PI_2))

self.rightSpace.constant = CGFloat(0)self.leftSpace.constant = CGFloat(0)self.topSpace.constant = CGFloat(0)self.bottomSpace.constant = CGFloat(0)

但正是在这一点上，我意识到我真的不需要更改间距值.我希望间距保持为 0.我只需要它自行调整.然而，旋转把这搞砸了.效果如下图所示:

我在尝试通过 HDMI/AirPlay 从 iOS 运行外部视频到旋转的电视屏幕时遇到了这个问题.

有时，电视会设置将信号旋转"90 度或 180 度等，但通常它没有该选项.

使用这样的包装"视图，我可以强制外部屏幕上的视图控制器旋转其内容，而内容实际上并不知道有什么不同.

让 contentsView = SomeWildCustomViewUsingAutoLayoutEtc()让 wrapper = RotatingWrapperView(contentsView)wrapper.translatesAutoresizingMaskIntoConstraints = falseparentView.addSubview(包装器)//...wrapper.rotation = .upsideDown

RotatingWrapperView 的来源:https://github.com/quantcon/UIKit/blob/master/AutoLayoutRotationDemo/Views/RotatingWrapperView.swift

I have learned how to rotate a view with Affine Transforms (see here). I have also learned about Auto Layout (see here and here), and even programmatic Auto Layout (see here and here). However, I don't know how to get Auto Layout to work with a rotated view.

This image shows what I would like to do:

I think the trouble comes from the width and the height changing because of the rotation. Is there any way to make a rotated view fill it's superview? Is there some trick to get Auto Layout to work or is it just incompatible after a rotation?

(I've only learned Swift, but I'd be glad to wade through Objective-C answers if that is what you are more familiar with.)

Update

Following @VinayJain's suggestion I did the following:

• pinned the subview edges to the superview in the storyboard.

• created IBOutlets for the spacing constraints on all sides of the subview.

  @IBOutlet weak var rightSpace: NSLayoutConstraint!
  @IBOutlet weak var leftSpace: NSLayoutConstraint!
  @IBOutlet weak var topSpace: NSLayoutConstraint!
  @IBOutlet weak var bottomSpace: NSLayoutConstraint!
  

• rotated the subview

  subview.transform = CGAffineTransformMakeRotation(CGFloat(M_PI_2))
  

• changed the constraints from the outlets

  self.rightSpace.constant = CGFloat(0)
  self.leftSpace.constant = CGFloat(0)
  self.topSpace.constant = CGFloat(0)
  self.bottomSpace.constant = CGFloat(0)
  

But it was at this point that I realized that I don't really need to change the spacing value. I want the spacing to remain 0. I just need it to adjust itself. However, the rotation messes that up. The effect is shown in the following image:

I came across this problem when trying to run external video over HDMI / AirPlay from iOS to a rotated TV screen.

Sometimes, the TV will have a setting to "rotate" the signal 90-degrees or 180-degrees, etc. but often times it will not have that option.

With a "wrapper" view like this, I am able to force the view controller on the external screen to rotate its contents without the contents actually being aware that anything is different.

let contentsView = SomeWildCustomViewUsingAutoLayoutEtc()
let wrapper = RotatingWrapperView(contentsView)
wrapper.translatesAutoresizingMaskIntoConstraints = false
parentView.addSubview(wrapper)
// ...
wrapper.rotation = .upsideDown

Source for RotatingWrapperView: https://github.com/quantcon/UIKit/blob/master/AutoLayoutRotationDemo/Views/RotatingWrapperView.swift

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