I'm well aware that there are only two available UIView transitions, UIViewAnimationTransitionFlipFromLeft and UIViewAnimationTransitionFlipFromRight. I'm wondering if there is anyway that I can implement / emulate a UIViewAnimationTransitionFlipFromTop or UIViewAnimationTransitionFlipFromBottom.
The only way I can think to do this is by flipping the x axis with the y axis, but I've not seen any information about how to do this. Just setting the coordinates of each axis won't fix the issue as the x-axis till remains the x-axis.
Does anyone have any ideas how this can be accomplished?
You can do this by applying a CATransform3D to your main view's CALayer, with your secondary view's CALayer behind it. In this response, I point to a Mac implementation of this animation by Mike Lee. You should be able to reuse a significant portion of that code to recreate this effect on the iPhone.
Guess you'll have to use a UIView animation block with a 3D rotation transform of 90 degrees, have the Core Animation delegate call you when that's done, swap the view with the new one (3D rotated on the other side) and chain with the last 90 degrees for the new view...
Although its not exactly what you want, there are two built-in animations that you didn't mention: UIViewAnimationTransitionCurlDown and UIViewAnimationTransitionCurlUp.
CurlUp looks like someone is peeling the view from the bottom up to the top, and CurlDown looks like the view is being unrolled down on top of the screen from top to bottom. You should at least give them a look, as they are easy to use.
Related
I have a custom UIView which I named UIWheel that I am rotating upon TouchDown. This UIWheel has many UIViews which I would like to rotate at the opposite direction (so that they remain appearing upright even after rotation) .
How do I code to tell it to get all of the UIViews in the UIWheel and in TouchDown rotate in the opposite direction?
Using the subviews property, iterate over each subview and rotate it exactly the way you rotate the outer view, but in the opposite direction.
As another option, you can move the part which you do want to rotate into its own subview, and just rotate that subview. It's a little counter-intuitive to rotate every object, then rotate a large number of them back into position.
I've learned that the best way to get graceful rotation is to set the auto rotation mask on the view that you want resize or move. This works fine if you're using SDK views like UILabel, but if you have your own custom view that uses the drawRect method it doesn't rotate as gracefully. In fact the only thing that happens is that it stretches whatever you drew in drawRect.
I've tried redrawing both before and after the rotation, but it doesn't give me that smooth rotation.
I looked at a UITextField auto rotating (flexible width) in slow motion and it follows the edge perfectly during the rotation. That is what I want my view to do, so how do I do that? My views jump to the right position either before or after the rotation.
The following line will make your UIView stretch the middle pixel only. If this is not your desired behavior I suggest you read the documentation for contentStretch to learn how to manipulate the values of the CGRect.
[self setContentStretch:CGRectMake(0.5, 0.5, 0.0, 0.0)];
I would guess that the UITextField you're looking at has at least three subviews, one displaying the left cap of the field's border, one displaying the right cap, and one displaying the middle, with autoresizing masks of "flexible right margin", "flexible left margin", and "flexible width", respectively. If you set up your custom view something like that, and make sure its autoresizesSubviews property is set to YES, then you should get the same smooth resize that the text field does.
I have a single UIView for drawing any one of a set of items. That is, my one UIView subclass can be told to draw a square, circle, or triangle for example.
I'd like to have a transition to flip that view so that the UIView draws a different shape at the half way point, so it looks like I'm transitioning to a different view, but really I'm just redrawing the single view at the half way point of the transition.
Is there a way to do this, without resorting to using two different UIViews and swapping them out in the animation block? It would be a bit clumsy for me to rejig what I have to use the swap mechanism.
Ideally all I need is some callback or notification that the animation is at the half way point, and then I can redraw the view with the new shape then.
Thanks for any help!
Even if you did know the midpoint of your flip animation, I don't believe redrawing the content of the view mid-animation would do anything. I think that the contents of the view's layer are cached at the beginning of the animation and don't change as the animation proceeds. Also, your view would end up inverted, left to right, at the end of the animation if you didn't have another view behind it.
If you wish to do this as a custom animation, you could break this into two halves using something like Mike Lee's Lemur Flip implementation that I describe in this answer. After the first half of the animation, you could redraw the view's content and complete the animation, ending up back where you started.
However, to me it seems more clumsy to not switch views in response to the transition. It certainly will take a lot more code to do.
you can try to do smth like this. For example, your animationDuration property is set to 2.0f. so, the half way point is 1 second, so you can use
[self performSelector:#selector(yourCallbackMethod) withObject:nil afterDelay:1.0f];
The only way I know of that you could do this is to re-create the animation using Core Animation and then monitor the animation in the presentationLayer using a timer. There is no KVO available in Core Animation Layers so you have to monitor it explicitly.
In other words, it's probably not worth it. I suggest you think of a different way to solve your problem.
I'm making an app where one of the objects needs to appear not to move or rotate during AutoRotation, but everything else needs to rotate and be repositioned. The way I did this is by manually rotating the object, and moving it into the same position, relative to the device, that it had prior to rotation. The problem is that it looks funny, appearing to rotate into the same position it had before.
If I suppress the animation effects during rotation, it would appear that the object never moved, and everything else just snapped into place, which is what I want. I haven't been able to find anything in the documentation that tells me how to do this though. How do I do this?
When it comes to UIViewController rotation there are two ways you can set up so you get a chance to rotate and move your own views.
In the one-step process, in your UIViewController-derived class provide an implementation of willAnimateRotationToInterfaceOrientation. It gets called and you can kick off your object rotation so while the system is rotating everything else your object is getting counter-rotated so it looks like it's staying put. You'll want to calculate how much to counter-rotate and in which direction based on current interface orientation vs. new orientation.
The other way is to get notified to do custom rotation in two steps. For example, in the first half you can shrink the object down, move it, and rotate it part way then in the second half finish the rotation as you scale back up to normal size. It's a pretty clever way to make the rotation animation look smoother to the eye.
For the two-step process, you need to define two methods. willAnimateFirstHalfOfRotationToInterfaceOrientation gets called for the first half of the rotation (i.e. up to 45 degrees for a 90 degree rotation and at 90 degrees for an upside down flip). Once past that point the second half is called via willAnimateSecondHalfOfRotationFromInterfaceOrientation.
If your object has a 1:1 aspect ratio (i.e square or round) and in the middle of the view then the one-step process will probably work fine. But if it's a non-square object and has to move position (for example if it's at position 40, 60 in portrait but moves to 20, 100 in landscape) and maybe even needs a bit of scaling to look better then you may want to try the two-step process and see if it looks smoother.
If your object is inside its own individual UIView then it's pretty easy to schedule the rotations through UIView animations. Just create a transform through CGAffineTransformMakeRotation, then inside a pair of UIView beginAnimations/commitAnimations blocks set the transform property of the view to this value. You can tweak the timing through setAnimationDuration.
EDIT: Based on the comments, I'm adding some code to show how you could attach the view to the top-level window instead of to the view controller. Your object would then reside in this view instead of the one managed by controller (which is getting rotated). You still need to over-ride the UIViewController rotate methods, but instead of rotating an object under control of the view controller you would trigger a counter-rotation in the object on the top-level.
To add a view to the top-level window:
YourAppDelegate* windowDelegate = ((YourAppDelegate*) [UIApplication sharedApplication].delegate);
[windowDelegate.window addSubview:yourView];
Keep a reference to yourView somewhere you can get to, then in the UIViewController's willAnimateRotationToInterfaceOrientation counter-rotate yourView, i.e. calculate how much to rotate the view in reverse to where you're going--if the phone is turning 90-degrees clockwise, you'll want to rotate the view back 90 degrees counter-clockwise, etc. Then use UIView animations on yourView.
If you don't want rotation animations, overload -shouldAutorotateToInterfaceOrientation: in your UIViewController and return NO. You can then observe UIDeviceOrientationDidChangeNotification to receive manual orientation change notifications.
This may work:
Listen for willRotateToInterfaceOrientation
[UIView setAnimationsEnabled:NO];
Listen for UIDeviceOrientationDidChangeNotification
[UIView setAnimationsEnabled:YES];
Untested, but I know that does work for some cases.
I've got a UIScrollview which fills a landscape screen, which contains a small tree of UIViews around inside it which I can scroll horizontally. I'd like to apply a barrel distortion to the scrollview, so that as the subviews move from the outside to the centre of the scrollview, they change shape.
What is a good what to go about applying distortions like this?
Is there a way to override drawRect for the scroll view, draw onto a bitmap, distort it, then draw that to the ScrollView's context instead? Or are there built in APIs to do this sort of distortion?
(source: arielnet.com)
You could get close to this effect by properly transforming the layers for each of your UIViews. Using a CATransform3D, you can rotate and translate each of the layers in 3-D, as well as apply a perspective effect. For your case, you can translate each of your UIView layers so that they are like a carousel, with the middle view forward and straight-on to the screen, and the side layers tilted and recessed slightly from the screen. This would not cause a curvature of the layers themselves (they will still be drawn as rectangles), but if you apply a transform on the main view's layer to create a perspective effect you should be able to get very close.
For an example of this kind of 3-D positioning of layers, I recommend this example where a full 3-D maze is constructed out of CALayers.
As far as the scroll view goes, you probably will have to do custom touch handling for this. You might be able to get by with respinding to the UIScrollViewDelegate methods like scrollViewDidScroll:, but I've not tried this myself.