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Why CAAnimation Rotation is returning to previous state
I'm trying to animate a rotation using CATransform3DMakeRotation, but the problem is once the animation is finished, the image goes back to its initial position, i.e back to zero. But I'd like to keep it where it finished rotating. How would I do that?
edit
What I'm trying to do is to create the same compass which comes with the new iPhone. Basically the locationmanager gives me new headings every few seconds (or several per second). Using the new heading and the timestamp, I was trying to get a smooth animation of the image but not getting anywhere. The only thing which seems to work is applying the transform directly, e.g.
compassimage.layer.transform = CATransform3DMakeRotation(newHeading.trueHeading *M_PI/180,0,0,1.0):
but that's not animated...
You should set the animation.removedOncompletion to NO
Ok, back to basics, just trying to rotate an image by 90 degrees and keeping it there. Added the following code to - (void)viewDidLoad but even though it rotates it still going back to it's initial position once the animation is finished
CATransform3D rotationTransform = CATransform3DMakeRotation(M_PI, 0, 0, 1.0);
CABasicAnimation* rotationAnimation;
rotationAnimation = [CABasicAnimation animationWithKeyPath:#"transform"];
rotationAnimation.toValue = [NSValue valueWithCATransform3D:rotationTransform];
rotationAnimation.duration = 2.0f;
rotationAnimation.removedOnCompletion = NO;
[image.layer addAnimation:rotationAnimation forKey:#"rotationAnimation"];
all you have to do is change the figure so that it is negative.
compassimage.layer.transform = CATransform3DMakeRotation(-newHeading.trueHeading *M_PI/180,0,0,1.0):
Related
I am using the accelerometer to move a sprite around the screen but I don't want to leave the screen.
I try with this
self.physicsWorld.contactDelegate = self;
self.physicsBody = [SKPhysicsBody bodyWithEdgeLoopFromRect:self.frame];
self.physicsBody.categoryBitMask = edgeCategory;
sprite.physicsBody.collisionBitMask = edgeCategory;
But the sprite still leaves the screen
I also change the scene anchor point
self.anchorPoint = CGPointMake(0.5, 0.5);
Try creating 4 rectangle SpriteNodes and making them very thin, long lines that make up your border. Give them all the same CategoryBitMask, etc.
This way, You can set the roof and floor using self.size.width as the length and around 1 or two as the thickness. Opposite for the Sides.
This will ignore the problem I think you are having where the scenes physicsBody rectangle is not centered to the middle of the screen.
If you did not previously do this, using your method:
Set sprite.categorybBitMask = spriteCategory;
Set self.collsionBitMask = spriteCategory;
one of the nodes MUST BE DYNAMIC! for collision to work.
I've created my own transition animation between views. I animate two properties, the position and the transform, to provide a cube-like transition between views. The frame uses CABasicAnimation while the transform uses a "2-stage" CAKeyframeAnimation. Everything works fine except for one small detail I can't seem to figure out. In my transition I apply a CATransform3DScale on the middle key frame to create a zoom-in/zoom-out effect. That works fine except the animation looks slightly jerky. It's animating the between the key frames in a linear fashion, and I would like to smooth that out. Now CAKeyframeAnimation has a way to do that using calculationMode, but it doesn't seem to work for transforms. I've tried setting it to kCAAnimationCubic and kCAAnimationCubicPaced with no effect.
Here is the code that animates one view's transform (a similar block of code animates the other view):
CAKeyframeAnimation *aTransform = [CAKeyframeAnimation animationWithKeyPath:#"transform"];
CATransform3D transform1 = RotateOnX(toView, M_PI_4);
transform1 = CATransform3DScale(transform1, RotationalZoom, RotationalZoom, RotationalZoom);
[aTransform setValues:Array([NSValue valueWithCATransform3D:RotateOnX(toView, M_PI_2)],
[NSValue valueWithCATransform3D:transform1],
[NSValue valueWithCATransform3D:RotateOnX(toView, 0)])];
[toView.layer addAnimation:aTransform forKey:#"transform"];
Note: RotateOnX(UIView *, CGFloat) is a block that returns a transform for a view rotated on X by the desired Radians.
As you can see I only set a scaling transform on the middle key frame. Also, the rotation of the view is perfectly smooth, it's only the scaling that appears to 'jerk' as it changes direction.
Does anyone have any ideas on how to smooth out the scaling/zooming?
Try the timingFunctions property. Since you have 3 keyframes, you need 2 timing functions: one for the animation from keyframe 0 to keyframe 1, and another for the animation from keyframe 1 to keyframe 2.
aTransform.timingFunctions = [NSArray arrayWithObjects:
[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInOut],
[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInOut],
nil];
FUTURE VIEWERS:
I have managed to finish this rotation animation and code with description can be found on tho question. NSImage rotation in NSView is not working
Before you proceed please up vote Duncan C 's answer. As I manage to achieve this rotation from his answer.
I have an image like this,
I want to keep rotating this sync icon, On a different thread. Now I tried using Quartz composer and add the animation to QCView but it is has very crazy effect and very slow too.
Question :
How do I rotate this image continuously with very less processing expense?
Effort
I read CoreAnimation, Quartz2D documentation but I failed to find the way to make it work. The only thing I know so far is, I have to use
CALayer
CAImageRef
AffineTransform
NSAnimationContext
Now, I am not expecting code, but an understanding with pseudo code will be great!
Getting an object to rotate more than 180 degrees is actually a little bit tricky. The problem is that you specify a transformation matrix for the ending rotation, and the system decides to rotate in the other direction.
What I've done is to create a CABasicAnimation of less than 180 degrees, set up to be additive , and with a repeat count. Each step in the animation animates the object more.
The following code is taken from an iOS application, but the technique is identical in Mac OS.
CABasicAnimation* rotate = [CABasicAnimation animationWithKeyPath: #"transform.rotation.z"];
rotate.removedOnCompletion = FALSE;
rotate.fillMode = kCAFillModeForwards;
//Do a series of 5 quarter turns for a total of a 1.25 turns
//(2PI is a full turn, so pi/2 is a quarter turn)
[rotate setToValue: [NSNumber numberWithFloat: -M_PI / 2]];
rotate.repeatCount = 11;
rotate.duration = duration/2;
rotate.beginTime = start;
rotate.cumulative = TRUE;
rotate.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
CAAnimation objects operate on layers, so for Mac OS, you'll need to set the "wants layer" property in interface builder, and then add the animation to your view's layer.
To make your view rotate forever, you'd set repeat count to some very large number like 1e100.
Once you've created your animation, you'd add it to your view's layer with code something like this:
[myView.layer addAnimation: rotate forKey: #"rotateAnimation"];
That's about all there is to it.
Update:
I've recently learned of another way to handle rotations of greater than 180 degrees, or continuous rotations.
There is a special object called a CAValueFunction that lets you apply a change to your layer's transform using an arbitrary value, including values that specify multiple full rotations.
You create a CABasicAnimation of your layer's transform property, but then instead of providing a transform, the value you supply is an NSNumber that gives the new rotation angle. If you provide a new angle like 20pi, your layer will rotate 10 full rotations (2pi/rotation). The code looks like this:
//Create a CABasicAnimation object to manage our rotation.
CABasicAnimation *rotation = [CABasicAnimation animationWithKeyPath:#"transform"];
rotation.duration = 10.0;
CGFLOAT angle = 20*M_PI;
//Set the ending value of the rotation to the new angle.
rotation.toValue = #(angle);
//Have the rotation use linear timing.
rotation.timingFunction =
[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
/*
This is the magic bit. We add a CAValueFunction that tells the CAAnimation we are
modifying the transform's rotation around the Z axis.
Without this, we would supply a transform as the fromValue and toValue, and
for rotations > a half-turn, we could not control the rotation direction.
By using a value function, we can specify arbitrary rotation amounts and
directions and even rotations greater than 360 degrees.
*/
rotation.valueFunction =
[CAValueFunction functionWithName: kCAValueFunctionRotateZ];
/*
Set the layer's transform to it's final state before submitting the animation, so
it is in it's final state once the animation completes.
*/
imageViewToAnimate.layer.transform =
CATransform3DRotate(imageViewToAnimate.layer.transform, angle, 0, 0, 1.0);
[imageViewToAnimate.layer addAnimation:rotation forKey:#"transform.rotation.z"];
(I Extracted the code above from a working example application, and took out some things that weren't directly related to the subject. You can see this code in use in the project KeyframeViewAnimations (link) on github. The code that does the rotation is in a method called `handleRotate'
I have a game where you have "specks" and "connectors".
I make a UIImageView that connects two "specks"… but as you can see (if the picture works), when the specks are almost on top of each other, like on the left, it doesn't work. This is my code… and I was wondering how you would make the rotation more accurate in that sort of situation.
UIImageView *connector = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"RedConnector.png"]];
connector.contentMode = UIViewContentModeScaleToFill;
connector.hidden = NO;
connector.alpha = 1;
connector.frame = CGRectMake(0, 0, [self DistanceBetweenPoints:speck1.center :speck2.center], 7);
connector.center = CGPointMake((speck1.center.x + speck2.center.x)/2, (speck1.center.y + speck2.center.y)/2);
//This is where the prob is:
connector.transform = CGAffineTransformMakeRotation(tanh((speck2.center.y - speck1.center.y)/(speck2.center.x - speck1.center.x)) );
[Connectors addObject:connector];
[self.view addSubview:connector];
"DistanceBetweenPoints" is not the problem. That works fine. Also, I know the center AND the frame is sort of redundant-- I'll work that out later. Third of all, I have made sure that two specks are never directly on top of each other (to never divide by zero). Last of all, I STILL WANT THESE TO BE UIIMAGEVIEWS!! So I can change the image and animate them so it looks like electricity flowing from speck to speck.
If anybody could show me how to make the rotation more accurate, it would be greatly appreciated. Thanks!
You should use atan2(y,x), not tanh(y/x). That is, you want the arctangent, not the hyperbolic tangent.
This question has been asked before but in a slightly different way and I was unable to get any of the answers to work the way I wanted, so I am hoping somebody with great Core Animation skills can help me out.
I have a set of cards on a table. As the user swipes up or down the set of cards move up and down the table. There are 4 cards visible on the screen at any given time, but only the second card is showing its face. As the user swipes the second card flips back onto its face and the next card (depending on the swipe direction) lands in it's place showing its face.
I have set up my card view class like this:
#interface WLCard : UIView {
UIView *_frontView;
UIView *_backView;
BOOL flipped;
}
And I have tried flipping the card using this piece of code:
- (void) flipCard {
[self.flipTimer invalidate];
if (flipped){
return;
}
id animationsBlock = ^{
self.backView.alpha = 1.0f;
self.frontView.alpha = 0.0f;
[self bringSubviewToFront:self.frontView];
flipped = YES;
CALayer *layer = self.layer;
CATransform3D rotationAndPerspectiveTransform = CATransform3DIdentity;
rotationAndPerspectiveTransform.m34 = 1.0 / 500;
rotationAndPerspectiveTransform = CATransform3DRotate(rotationAndPerspectiveTransform, M_PI, 1.0f, 0.0f, 0.0f);
layer.transform = rotationAndPerspectiveTransform;
};
[UIView animateWithDuration:0.25
delay:0.0
options: UIViewAnimationCurveEaseInOut
animations:animationsBlock
completion:nil];
}
This code works but it has the following problems with it that I can't seem to figure out:
Only half of the card across the x-axis is animated.
Once flipped, the face of the card is upside down and mirrored.
Once I've flipped the card I cannot get the animation to ever run again. In other words, I can run the animation block as many times as I want, but only the first time will animate. The subsequent times I try to animate lead to just a fade in and out between the subviews.
Also, bear in mind that I need to be able to interact with the face of the card. i.e. it has buttons on it.
If anybody has run into these issues it would be great to see your solutions. Even better would be to add a perspective transform to the animation to give it that extra bit of realism.
This turned out to be way simpler than I thought and I didn't have to use any CoreAnimation libraries to achieve the effect. Thanks to #Aaron Hayman for the clue. I used transitionWithView:duration:options:animations:completion
My implementation inside the container view:
[UIView transitionWithView:self
duration:0.2
options:UIViewAnimationOptionTransitionFlipFromBottom
animations: ^{
[self.backView removeFromSuperview];
[self addSubview:self.frontView];
}
completion:NULL];
The trick was the UIViewAnimationOptionTransitionFlipFromBottom option. Incidentally, Apple has this exact bit of code in their documentation. You can also add other animations to the block like resizing and moving.
Ok, this won't be a complete solution but I'll point out some things that might be helpful. I'm not a Core-Animation guru but I have done a few 3D rotations in my program.
First, there is no 'back' to a view. So if you rotate something by M_PI (180 degrees) you're going to be looking at that view as though from the back (which is why it's upside down/mirrored).
I'm not sure what you mean by:
Only half of the card across the x-axis is animated.
But, it it might help to consider your anchor point (the point at which the rotation occurs). It's usually in the center, but often you need it to be otherwise. Note that anchor points are expressed as a proportion (percentage / 100)...so the values are 0 - 1.0f. You only need to set it once (unless you need it to change). Here's how you access the anchor point:
layer.anchorPoint = CGPointMake(0.5f, 0.5f) //This is center
The reason the animation only ever runs once is because transforms are absolute, not cumulative. Consider that you're always starting with the identity transform and then modifying that, and it'll make sense...but basically, no animation occurs because there's nothing to animate the second time (the view is already in the state you're requesting it to be in).
If you're animating from one view to another (and you can't use [UIView transitionWithView:duration:options:animations:completion:];) you'l have to use a two-stage animation. In the first stage of the animation, for the 'card' that is being flipped to backside, you'll rotate the view-to-disappear 'up/down/whatever' to M_PI_2 (at which point it will be 'gone', or not visible, because of it's rotation). And in the second stage, you're rotate the backside-of-view-to-disappear to 0 (which should be the identity transform...aka, the view's normal state). In addition, you'll have to do the exact opposite for the 'card' that is appearing (to frontside). You can do this by implementing another [UIView animateWithDuration:...] in the completion block of the first one. I'll warn you though, doing this can get a little bit complicated. Especially since you're wanting views to have a 'backside', which will basically require animating 4 views (the view-to-disappear, the view-to-appear, backside-of-view-to-disappear, and the backside-of-view-to-appear). Finally, in the completion block of the second animation you can do some cleanup (reset view that are rotated and make their alpha 0.0f, etc...).
I know this is complicated, so you might want read some tutorial on Core-Animation.
#Aaron has some good info that you should read.
The simplest solution is to use a CATransformLayer that will allow you to place other CALayer's inside and maintain their 3D hierarchy.
For example to create a "Card" that has a front and back you could do something like this:
CATransformLayer *cardContainer = [CATransformLayer layer];
cardContainer.frame = // some frame;
CALayer *cardFront = [CALayer layer];
cardFront.frame = cardContainer.bounds;
cardFront.zPosition = 2; // Higher than the zPosition of the back of the card
cardFront.contents = (id)[UIImage imageNamed:#"cardFront"].CGImage;
[cardContainer addSublayer:cardFront];
CALayer *cardBack = [CALayer layer];
cardBack.frame = cardContainer.bounds;
cardBack.zPosition = 1;
cardBack.contents = (id)[UIImage imageNamed:#"cardBack"].CGImage; // You may need to mirror this image
[cardContainer addSublayer:cardBack];
With this you can now apply your transform to cardContainer and have a flipping card.
#Paul.s
I followed your approach with card container but when i applt the rotation animation on card container only one half of the first card rotates around itself and finally the whole view appears.Each time one side is missing in the animation
Based on Paul.s this is updated for Swift 3 and will flip a card diagonally:
func createLayers(){
transformationLayer = CATransformLayer(layer: CALayer())
transformationLayer.frame = CGRect(x: 15, y: 100, width: view.frame.width - 30, height: view.frame.width - 30)
let black = CALayer()
black.zPosition = 2
black.frame = transformationLayer.bounds
black.backgroundColor = UIColor.black.cgColor
transformationLayer.addSublayer(black)
let blue = CALayer()
blue.frame = transformationLayer.bounds
blue.zPosition = 1
blue.backgroundColor = UIColor.blue.cgColor
transformationLayer.addSublayer(blue)
let tgr = UITapGestureRecognizer(target: self, action: #selector(recTap))
view.addGestureRecognizer(tgr)
view.layer.addSublayer(transformationLayer)
}
Animate a full 360 but since the layers have different zPositions the different 'sides' of the layers will show
func recTap(){
let animation = CABasicAnimation(keyPath: "transform")
animation.delegate = self
animation.duration = 2.0
animation.fillMode = kCAFillModeForwards
animation.isRemovedOnCompletion = false
animation.toValue = NSValue(caTransform3D: CATransform3DMakeRotation(CGFloat(Float.pi), 1, -1, 0))
transformationLayer.add(animation, forKey: "arbitrarykey")
}