I have created a circle using CAShapeLayer. I want to rotate this circle at fix centre. i'm using following code for animation. Using this code circle is rotating but not at a fix centre. Is centre keeps on changing. I don't want that to happen.
This is my code for animation
CABasicAnimation* rotationAnimation;
rotationAnimation = [CABasicAnimation animationWithKeyPath:#"transform.rotation.z"];
rotationAnimation.toValue = [NSNumber numberWithFloat: M_PI * 2.0 * rotations * 2.0 ];
rotationAnimation.duration = 10.0; // rotationAnimation.cumulative = YES;
rotationAnimation.repeatCount = 1.0;
rotationAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
[circle1 addAnimation:rotationAnimation forKey:#"rotationAnimation"];
Thanks
This will keep it inside rect.
[circle1 setAnchorPoint:(0.5,0.5)];
CGFloat angle = rotationAnimation.toValue;
CGFloat radius = someRadius;
CGPoint rotationCenter = CGPointMake(centerX,centerY);
circle1.frame = CGRectMake(rotationCenter.x + radius * cos(angle), rotationCenter.y + radius * sin(angle), circle1.frame.size.width, circle1.frame.size.height);
Related
I am developing a small game in iphone... Game concept is place an object in top of the bar...Rotating a bar using accelerometer. When bar rotating , i need to move an object with respect to bar. How to implement this concept...Any examples or references?
Rotating both img:
barImg,objImg //UIImageView
barImg.transform = CGAffineTransformMakeRotation(Ypos);
objImg.transform=CGAffineTransformMakeRotation(Ypos);
So for rotating 360 Degree with animation:
CABasicAnimation *rotationAnimation;
rotationAnimation = [CABasicAnimation animationWithKeyPath:#"transform.rotation.z"];
rotationAnimation.toValue = [NSNumber numberWithFloat:-M_PI * 2.0]; // full rotation*/ * rotations * duration ];
rotationAnimation.duration = 1;
rotationAnimation.cumulative = YES;
rotationAnimation.repeatCount = MAXFLOAT;
[rotatingTelIamgeview.layer addAnimation:rotationAnimation forKey:#"rotationAnimation"];
you can play with toValue for changing the angle.
For moving an object:
CGPoint startPoint = CGPointMake(lvMessageInputBar.animationBubbleImageView.layer.frame.origin.x+lvMessageInputBar.animationBubbleImageView.layer.frame.size.width/2
, lvMessageInputBar.animationBubbleImageView.layer.frame.origin.y +lvMessageInputBar.animationBubbleImageView.layer.frame.size.height/2 );
CGPoint endPoint = CGPointMake(endPoint.origin.x+Endpoint.size.width/2, bubleRect.origin.y+bubleRect.size.height/2);
CGPoint middlePoint = // any point between start and end corrdinates
CGMutablePathRef path = CGPathCreateMutable();
CGPathMoveToPoint(path, NULL, startPoint.x, startPoint.y);
CGPathAddQuadCurveToPoint(path, NULL,middlePoint.x, middlePoint.y,endPoint.x,endPoint.y);
CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:#"position"];
pathAnimation.delegate = self;
pathAnimation.removedOnCompletion = NO;
pathAnimation.path = path;
[pathAnimation setCalculationMode:kCAAnimationCubic];
[pathAnimation setFillMode:kCAFillModeForwards];
pathAnimation.duration = 0.3;
[lvMessageInputBar.animationBubbleImageView.layer addAnimation:pathAnimation forKey:nil];
The above example moves the layer of the object over a path.but CGPathAddQuadCurveToPoint makes the path not diagonal rather circular path (curve).
you can use CGPathAddPath if you do not want this effect.
If you are new to iPhone I would start with layer tutorial to get the idea behind CALayer and then take a look CALayer animations
CALayers introduction:
https://www.raywenderlich.com/3096-calayers-tutorial-for-ios-introduction-to-calayers
CALayer Animation documentation of from Apple:
https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/CoreAnimation_guide/Introduction/Introduction.html
You can also watch Session 424 (Core Animation in Practice, Part 1) and 425 (Core Animation in Practice, Part 2) of WWDC 2010:
https://developer.apple.com/videos/archive/
Hi I have a UIImageView which is part on, part off screen.
I want to rotate the view around a point off screen (the center of the view.)
How do I do this?
fullRotationAnimation = [CABasicAnimation animationWithKeyPath:#"transform.rotation"];
fullRotationAnimation.fromValue= [NSNumber numberWithFloat:0.0f];
fullRotationAnimation.toValue = [NSNumber numberWithFloat:2 * M_PI];
fullRotationAnimation.duration = 4;
fullRotationAnimation.repeatCount = 1;
[self->greyRings.layer addAnimation:fullRotationAnimation forKey:#"360"];
I'm using that code at the moment but it just spins it around the center of the screen.
Any ideas please?
Using block animation:
- (void)rotateImageView:(UIImageView *)imageView aroundPoint:(CGPoint)point byAngle:(CGFloat)angle {
CGFloat sinA = sin(angle);
CGFloat cosA = cos(angle);
CGFloat x = point.x;
CGFloat y = point.y;
CGAffineTransform transform = CGAffineTransformMake(cosA,sinA,-sinA,cosA,x-x*cosA+y*sinA,y-x*sinA-y*cosA);
[UIView animateWithDuration:4.0 animations:^{
imageView.transform = transform;
}];
}
Note that angle is in radians, so a full rotation is 2.0*M_PI.
Maybe you have to set anchorPoint of CALayer: see Specifying a Layer’s Geometry for more detail.
//(0,0) is the left-bottom of your layer bounds
self->greyRings.layer.anchorPoint = CGPointMake(0.0f, 0.0f);
I think a negative anchorPoint should also work. So you'd better give your bounds and we can calculate for you.
I've started using CATransform3D lately and it seems very nice. I just have 1 issue with the rotation though. I'm trying to rotate my view for 360˚ degrees to the right but if I just put pass 360 to CATransform3DRotate it doesn't work (It just doesn't move at all.)
Here's my code:
CALayer *layer = dock.layer;
CATransform3D r = CATransform3DIdentity;
r.m34 = 1.0 / -500;
r = CATransform3DRotate(r, DegreesToRadians(360.0f), 100.0f, 1.0f, 100.0f);
layer.transform = r;
Does anyone know how to fix this issue? Thanks in advance! :)
You can animate a layer through one (or more) full rotations around its Z axis by animating the layer's transform.rotation key path, like this:
CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:#"transform.rotation"];
animation.duration = .25;
animation.fromValue = [NSNumber numberWithFloat:0];
animation.toValue = [NSNumber numberWithFloat:2 * M_PI];
[layer addAnimation:animation forKey:animation.keyPath];
You can animate around the X or Y axes using the key paths transform.rotation.x and transform.rotation.y. (The transform.rotation.z key path has the same effect as the transform.rotation key path.) You can apply multiple rotations, on separate axes, simultaneously.
Another way to do it, which probably works better if you want to rotate around an off-axis vector, is using a keyframe animation, like this:
CALayer *layer = [sender layer];
CATransform3D transform = CATransform3DIdentity;
transform.m34 = 1.0 / -50;
layer.transform = transform;
CAKeyframeAnimation *animation = [CAKeyframeAnimation animationWithKeyPath:#"transform"];
animation.values = [NSArray arrayWithObjects:
[NSValue valueWithCATransform3D:CATransform3DRotate(transform, 0 * M_PI / 2, 100, 1, 100)],
[NSValue valueWithCATransform3D:CATransform3DRotate(transform, 1 * M_PI / 2, 100, 1, 100)],
[NSValue valueWithCATransform3D:CATransform3DRotate(transform, 2 * M_PI / 2, 100, 1, 100)],
[NSValue valueWithCATransform3D:CATransform3DRotate(transform, 3 * M_PI / 2, 100, 1, 100)],
[NSValue valueWithCATransform3D:CATransform3DRotate(transform, 4 * M_PI / 2, 100, 1, 100)],
nil];
animation.duration = 2;
[layer addAnimation:animation forKey:animation.keyPath];
I have been trying for the last few days to create the ken burns effect using a CALayer with animations and then save it to a video file.
I have my image layer which is inside another layer that is 1024x576. All of the animations are applied to the image layer.
Here is the code so far:
- (CALayer*)buildKenBurnsLayerWithImage:(UIImage *)image startPoint:(CGPoint)startPoint endPoint:(CGPoint)endPoint fromScale:(float)fromScale toScale:(float)toScale
{
float calFromScale = fromScale + 1;
float calToScale = toScale + 1;
float fromX = startPoint.x * calFromScale;
float fromY = (image.size.height * calFromScale) - (videoSize.height + (startPoint.y * calFromScale));
float toX = endPoint.x * calToScale;
float toY = (image.size.height * calToScale) - (videoSize.height + (endPoint.y * calToScale));
CGPoint anchor = CGPointMake(0.0, 0.0);
CALayer* imageLayer = [CALayer layer];
imageLayer.contents = (id)image.CGImage;
imageLayer.anchorPoint = anchor;
imageLayer.bounds = CGRectMake(0.0, 0.0, image.size.width, image.size.height);
imageLayer.position = CGPointMake(image.size.width * anchor.x, image.size.height * anchor.y);
imageLayer.contentsGravity = kCAGravityResizeAspect;
// create the panning animation.
CABasicAnimation* panningAnimation = [CABasicAnimation animationWithKeyPath:#"position"];
panningAnimation.fromValue = [NSValue valueWithCGPoint:CGPointMake(-fromX, -fromY)];
panningAnimation.toValue = [NSValue valueWithCGPoint:CGPointMake(-toX, -toY)];
panningAnimation.additive = YES;
panningAnimation.removedOnCompletion = NO;
// create the scale animation.
CABasicAnimation* scaleAnimation = [CABasicAnimation animationWithKeyPath:#"transform.scale"];
scaleAnimation.fromValue = [NSNumber numberWithFloat:fromScale];
scaleAnimation.toValue = [NSNumber numberWithFloat:toScale];
scaleAnimation.additive = YES;
scaleAnimation.removedOnCompletion = NO;
CAAnimationGroup* animationGroup = [CAAnimationGroup animation];
animationGroup.animations = [[NSMutableArray alloc] initWithObjects:panningAnimation,scaleAnimation, nil];
animationGroup.beginTime = 1e-100;
animationGroup.duration = 5.0;
animationGroup.removedOnCompletion = NO;
animationGroup.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
[imageLayer addAnimation:animationGroup forKey:nil];
return imageLayer;
}
Here is how i'm calling the method:
CALayer* animatedLayer = [self buildKenBurnsLayerWithImage:image startPoint:CGPointMake(100, 100) endPoint:CGPointMake(500, 500) fromScale:5.0 toScale:2.0];
The problem I am having is that the end result with panning and scaling is off by a few pixels on the screen.
If someone knows how to fix this i would great appreciate it.
All transformations are applied with respect to the anchor point. Try using the anchor point
CGPoint anchor = CGPointMake(0.5f, 0.5f);
Your "viewport" should no longer scale to the bottom right (if that is responsible for the animation being off by a few pixels), but equally to all directions.
How can we Move an Image 360 Degree from the starting point to the ending point?
Moving Image 360 Degree?
You can rotate a view, by some number of radians, regardless of whether it is less than a full rotation or many multiples of a full rotation, without having to split the rotation into pieces. As an example, the following code will spin a view, once per second, for a specified number of seconds. You can easily modify it to spin a view by a certain number of rotations, or by some number of radians.
- (void) runSpinAnimationWithDuration:(CGFloat) duration;
{
CABasicAnimation* rotationAnimation;
rotationAnimation = [CABasicAnimation animationWithKeyPath:#"transform.rotation.z"];
rotationAnimation.toValue = [NSNumber numberWithFloat: M_PI * 2.0 /* full rotation*/ * rotations * duration ];
rotationAnimation.duration = duration;
rotationAnimation.cumulative = YES;
rotationAnimation.repeatCount = 1.0;
rotationAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
[myView.layer addAnimation:rotationAnimation forKey:#"rotationAnimation"];
}
A 360 degree rotation in any axis leaves the view unchanged. So don't touch the image, and you're good to go!
You could use an animation function (CAValueFunction) for this too:
CABasicAnimation *rotationAnimation = [CABasicAnimation animationWithKeyPath:#"transform"];
rotationAnimation.duration = duration;
rotationAnimation.fromValue = [NSNumber numberWithFloat:0.0];
rotationAnimation.toValue = [NSNumber numberWithFloat:M_PI * 2.0];
rotationAnimation.valueFunction = [CAValueFunction functionWithName:kCAValueFunctionRotateZ];
rotationAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
[myView.layer addAnimation:rotationAnimation forKey:nil];