As Ben said, you'll need to work with the UIView's
layer, using a CATransform3D
to perform the layer's
rotation
. The trick to get perspective working, as described here, is to directly access one of the matrix cells
of the CATransform3D
(m34). Matrix math has never been my thing, so I can't explain exactly why this works, but it does. You'll need to set this value to a negative fraction for your initial transform, then apply your layer rotation transforms to that. You should also be able to do the following:
Objective-C
UIView *myView = [[self subviews] objectAtIndex:0];
CALayer *layer = myView.layer;
CATransform3D rotationAndPerspectiveTransform = CATransform3DIdentity;
rotationAndPerspectiveTransform.m34 = 1.0 / -500;
rotationAndPerspectiveTransform = CATransform3DRotate(rotationAndPerspectiveTransform, 45.0f * M_PI / 180.0f, 0.0f, 1.0f, 0.0f);
layer.transform = rotationAndPerspectiveTransform;
Swift 5.0
if let myView = self.subviews.first {
let layer = myView.layer
var rotationAndPerspectiveTransform = CATransform3DIdentity
rotationAndPerspectiveTransform.m34 = 1.0 / -500
rotationAndPerspectiveTransform = CATransform3DRotate(rotationAndPerspectiveTransform, 45.0 * .pi / 180.0, 0.0, 1.0, 0.0)
layer.transform = rotationAndPerspectiveTransform
}
which rebuilds the layer transform from scratch for each rotation.
A full example of this (with code) can be found here, where I've implemented touch-based rotation and scaling on a couple of CALayers
, based on an example by Bill Dudney. The newest version of the program, at the very bottom of the page, implements this kind of perspective operation. The code should be reasonably simple to read.
The sublayerTransform
you refer to in your response is a transform that is applied to the sublayers of your UIView's
CALayer
. If you don't have any sublayers, don't worry about it. I use the sublayerTransform in my example simply because there are two CALayers
contained within the one layer that I'm rotating.
Already asked, but with a very different title.
What #defines are set up by Xcode when compiling for iPhone
I'll repeat my answer from there:
It's in the SDK docs under "Compiling source code conditionally"
The relevant definition is TARGET_OS_SIMULATOR, which is defined in /usr/include/TargetConditionals.h within the iOS framework. On earlier versions of the toolchain, you had to write:
#include "TargetConditionals.h"
but this is no longer necessary on the current (Xcode 6/iOS8) toolchain.
So, for example, if you want to check that you are running on device, you should do
#if TARGET_OS_SIMULATOR
// Simulator-specific code
#else
// Device-specific code
#endif
depending on which is appropriate for your use-case.
Best Answer
You should use UIImageView. It is a subclass of UIView and you can set the image with an instance on UIImage.
Here is an example to add it to another UIView.