This class will put perspective on an upright image.
It works perfectly BUT does not work live in Storyboard with IBDesignable. Which is very sad.
Is it possible to use CATransform3D and the like for live display on Storyboard with IBDesignable??
// Twist.swift .. twist on Y, perspective from the left
import UIKit
@IBDesignable
class Twist:UIViewController
{
@IBInspectable var perspective:CGFloat = 0.5 // -1 to 1
@IBOutlet var im:UIView! // the image you want to twist on y
override func prepareForInterfaceBuilder()
{ twist(perspective) }
override func viewDidAppear(animated: Bool)
{
twist(perspective)
super.viewWillAppear(animated)
}
func twist(f:CGFloat) // -1 to 1
{
// hinge around left edge
im.layer.anchorPoint = CGPointMake(0, 0.5)
im.center = CGPointMake(0.0, self.view.bounds.size.height/2.0)
// base transform, twist on y
var t:CATransform3D = CATransform3DIdentity
t.m34 = -1/500
im.layer.transform = t
im.layer.transform = CATransform3DRotate(t, f*CGFloat(M_PI_2), 0, 1, 0);
}
}
来源:https://stackoverflow.com/questions/37311649/layer-transform-matrix-catransform3d-etc-but-with-ibdesignable