iOS Swift: Rotate and Scale UIView without resizing - ios

I have a UIView which i want to scale and rotate via pan and pinch gesture. But issue is when i scale view and after then when i rotate it's resizing back to initial value before scaling.
extension UIView {
func addPinchGesture() {
var pinchGesture = UIPinchGestureRecognizer()
pinchGesture = UIPinchGestureRecognizer(target: self,
action: #selector(handlePinchGesture(_:)))
self.addGestureRecognizer(pinchGesture)
}
#objc func handlePinchGesture(_ sender: UIPinchGestureRecognizer) {
self.transform = self.transform.scaledBy(x: sender.scale, y: sender.scale)
sender.scale = 1
}
}
// ROTATION
extension UIView {
func addRotationGesture() {
var rotationGesture = RotationGestureRecognizer()
rotationGesture = RotationGestureRecognizer(target: self,
action: #selector(handleRotationGesture(_:)))
self.addGestureRecognizer(rotationGesture)
}
#objc func handleRotationGesture(_ sender: RotationGestureRecognizer) {
var originalRotation = CGFloat()
switch sender.state {
case .began:
sender.rotation = sender.lastRotation
originalRotation = sender.rotation
case .changed:
let newRotation = sender.rotation + originalRotation
self.transform = CGAffineTransform(rotationAngle: newRotation) // Rotation is fine but it is resizing view
// self.transform = self.transform.rotated(by: newRotation / CGFloat(180 * Double.pi)) // NOT WORKING i.e. irregular rotation
case .ended:
sender.lastRotation = sender.rotation
default:
break
}
}
}
Before Scaling
After Scaling
After Rotation
I want it to be rotate without affecting view size. How can i achieve that?

You are resetting the scale transform of view when applying rotation transform. Create a property to hold original scale of the view.
var currentScale: CGFloat = 0
And when pinch is done, store the currentScale value to current scale. Then when rotating also use this scale, before applying the rotation.
let scaleTransform = CGAffineTransform(scaleX: currentScale, y: currentScale)
let concatenatedTransform = scaleTransform.rotated(by: newRotation)
self.transform = concatenatedTransform
You are using extension to add gesture recognizers, for that reason you cannot store currentScale. You can also get the scale values of view from current transform values. Here is how your code would look like,
extension UIView {
var currentScale: CGPoint {
let a = transform.a
let b = transform.b
let c = transform.c
let d = transform.d
let sx = sqrt(a * a + b * b)
let sy = sqrt(c * c + d * d)
return CGPoint(x: sx, y: sy)
}
func addPinchGesture() {
var pinchGesture = UIPinchGestureRecognizer()
pinchGesture = UIPinchGestureRecognizer(target: self,
action: #selector(handlePinchGesture(_:)))
self.addGestureRecognizer(pinchGesture)
}
#objc func handlePinchGesture(_ sender: UIPinchGestureRecognizer) {
self.transform = self.transform.scaledBy(x: sender.scale, y: sender.scale)
sender.scale = 1
}
}
// ROTATION
extension UIView {
func addRotationGesture() {
var rotationGesture = RotationGestureRecognizer()
rotationGesture = RotationGestureRecognizer(target: self,
action: #selector(handleRotationGesture(_:)))
self.addGestureRecognizer(rotationGesture)
}
#objc func handleRotationGesture(_ sender: RotationGestureRecognizer) {
var originalRotation = CGFloat()
switch sender.state {
case .began:
sender.rotation = sender.lastRotation
originalRotation = sender.rotation
case .changed:
let scale = CGAffineTransform(scaleX: currentScale.x, y: currentScale.y)
let newRotation = sender.rotation + originalRotation
self.transform = scale.rotated(by: newRotation)
case .ended:
sender.lastRotation = sender.rotation
default:
break
}
}
}
I used this answer as a reference for extracting the scale value.

I was facing the same issue Once I pinch from a finger, then after I rotate from a button it automatically scales down from the current but I set logic below.
#objc func rotateViewPanGesture(_ recognizer: UIPanGestureRecognizer) {
touchLocation = recognizer.location(in: superview)
let center = CGRectGetCenter(frame)
switch recognizer.state {
case .began:
deltaAngle = atan2(touchLocation!.y - center.y, touchLocation!.x - center.x) - CGAffineTrasformGetAngle(transform)
initialBounds = bounds
initialDistance = CGpointGetDistance(center, point2: touchLocation!)
case .changed:
let ang = atan2(touchLocation!.y - center.y, touchLocation!.x - center.x)
let angleDiff = deltaAngle! - ang
let a = transform.a
let b = transform.b
let c = transform.c
let d = transform.d
let sx = sqrt(a * a + b * b)
let sy = sqrt(c * c + d * d)
let currentScale = CGPoint(x: sx, y: sy)
let scale = CGAffineTransform(scaleX: currentScale.x, y: currentScale.y)
self.transform = scale.rotated(by: -angleDiff)
layoutIfNeeded()
case .ended:
print("end gesture status")
default:break
}
}

Related

Completion block of animation is performed immediately

I'm trying to remove the custom view from the superview after the end of the animation in the completion block, but it is called immediately and the animation becomes sharp. I managed to solve the problem in a not very good way: just adding a delay to remove the view.
Here is the function for animating the view:
private func animatedHideSoundView(toRight: Bool) {
let translationX = toRight ? 0.0 : -screenWidth
UIView.animate(withDuration: 0.5) {
self.soundView.transform = CGAffineTransform(translationX: translationX, y: 0.0)
} completion: { isFinished in
if isFinished {
self.soundView.removeFromSuperview()
self.songPlayer.pause()
}
}
}
The problem in this line: self.soundView.removeFromSuperview()
When I call this function in the switch recognizer.state completion block statement it executes early and when elsewhere everything works correctly.
#objc private func soundViewPanned(recognizer: UIPanGestureRecognizer) {
let touchPoint = recognizer.location(in: view)
switch recognizer.state {
case .began:
initialOffset = CGPoint(x: touchPoint.x - soundView.center.x, y: touchPoint.y - soundView.center.y)
case .changed:
soundView.center = CGPoint(x: touchPoint.x - initialOffset.x, y: touchPoint.y - initialOffset.y)
if notHiddenSoundViewRect.minX > soundView.frame.minX {
animatedHideSoundView(toRight: false)
} else if notHiddenSoundViewRect.maxX < soundView.frame.maxX {
animatedHideSoundView(toRight: true)
}
case .ended, .cancelled:
let decelerationRate = UIScrollView.DecelerationRate.normal.rawValue
let velocity = recognizer.velocity(in: view)
let projectedPosition = CGPoint(
x: soundView.center.x + project(initialVelocity: velocity.x, decelerationRate: decelerationRate),
y: soundView.center.y + project(initialVelocity: velocity.y, decelerationRate: decelerationRate)
)
let nearestCornerPosition = nearestCorner(to: projectedPosition)
let relativeInitialVelocity = CGVector(
dx: relativeVelocity(forVelocity: velocity.x, from: soundView.center.x, to: nearestCornerPosition.x),
dy: relativeVelocity(forVelocity: velocity.y, from: soundView.center.y, to: nearestCornerPosition.y)
)
let timingParameters = UISpringTimingParameters(dampingRatio: 0.8, initialVelocity: relativeInitialVelocity)
let animator = UIViewPropertyAnimator(duration: 0.5, timingParameters: timingParameters)
animator.addAnimations {
self.soundView.center = nearestCornerPosition
}
animator.startAnimation()
default: break
}
}
I want the user to be able to swipe this soundView off the screen.
That's why I check where the soundView is while the user is moving it, so that if he moves the soundView near the edge of the screen, I can hide the soundView animatedly.
Maybe I'm doing it wrong, but I couldn't think of anything else, because I don't have much experience. Could someone give me some advice on this?
I managed to solve it this way, but I don't like it:
private func animatedHideSoundView(toRight: Bool) {
let translationX = toRight ? 0.0 : -screenWidth
UIView.animate(withDuration: 0.5) {
self.soundView.transform = CGAffineTransform(translationX: translationX, y: 0.0)
}
DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
self.soundView.removeFromSuperview()
self.songPlayer.pause()
}
}
enter image description here
You can see and run all code here: https://github.com/swiloper/AnimationProblem
Couple notes...
First, in your controller code, you are calling animatedHideSoundView() from your pan gesture recognizer every time you move the touch. It's unlikely that's what you want to do.
Second, if you call animatedHideSoundView(toRight: true) your code:
private func animatedHideSoundView(toRight: Bool) {
let translationX = toRight ? 0.0 : -screenWidth
UIView.animate(withDuration: 0.5) {
self.soundView.transform = CGAffineTransform(translationX: translationX, y: 0.0)
} completion: { isFinished in
if isFinished {
self.soundView.removeFromSuperview()
self.songPlayer.pause()
}
}
}
sets translationX to Zero ... when you then try to animate the transform, the animation will take no time because you're not changing the x.
Third, I strongly suggest that you start simple. The code you linked to cannot be copy/pasted/run, which makes it difficult to offer help.
Here's a minimal version of your UniversalTypesViewController class (it uses your linked SoundView class):
final class UniversalTypesViewController: UIViewController {
// MARK: Properties
private lazy var soundView = SoundView(frame: CGRect(x: 0, y: 0, width: 80, height: 80))
private let panGestureRecognizer = UIPanGestureRecognizer()
private var initialOffset: CGPoint = .zero
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .systemYellow
panGestureRecognizer.addTarget(self, action: #selector(soundViewPanned(recognizer:)))
soundView.addGestureRecognizer(panGestureRecognizer)
}
private func animatedShowSoundView() {
// reset soundView's transform
soundView.transform = .identity
// add it to the view
view.addSubview(soundView)
// position soundView near bottom, but past the right side of view
soundView.frame.origin = CGPoint(x: view.frame.width, y: view.frame.height - soundView.frame.height * 2.0)
soundView.startSoundBarsAnimation()
// animate soundView into view
UIView.animate(withDuration: 0.5, delay: 0.0, options: .curveEaseOut) {
self.soundView.transform = CGAffineTransform(translationX: -self.soundView.frame.width * 2.0, y: 0.0)
}
}
private func animatedHideSoundView(toRight: Bool) {
let translationX = toRight ? view.frame.width : -(view.frame.width + soundView.frame.width)
UIView.animate(withDuration: 0.5) {
self.soundView.transform = CGAffineTransform(translationX: translationX, y: 0.0)
} completion: { isFinished in
if isFinished {
self.soundView.removeFromSuperview()
//self.songPlayer.pause()
}
}
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
// if soundView is not in the view hierarchy,
// animate it into view - animatedShowSoundView() func adds it as a subview
if soundView.superview == nil {
animatedShowSoundView()
} else {
// unwrap the touch
guard let touch = touches.first else { return }
// get touch location
let loc = touch.location(in: self.view)
// if touch is inside the soundView frame,
// return, so pan gesture can move soundView
if soundView.frame.contains(loc) { return }
// if touch is on the left-half of the screen,
// animate soundView to the left and remove after animation
if loc.x < view.frame.midX {
animatedHideSoundView(toRight: false)
} else {
// touch is on the right-half of the screen,
// so just remove soundView
animatedHideSoundView(toRight: true)
}
}
}
// MARK: Objc methods
#objc private func soundViewPanned(recognizer: UIPanGestureRecognizer) {
let touchPoint = recognizer.location(in: view)
switch recognizer.state {
case .began:
initialOffset = CGPoint(x: touchPoint.x - soundView.center.x, y: touchPoint.y - soundView.center.y)
case .changed:
soundView.center = CGPoint(x: touchPoint.x - initialOffset.x, y: touchPoint.y - initialOffset.y)
case .ended, .cancelled:
()
default: break
}
}
}
If you run that, tapping anywhere will animate soundView into view at bottom-right. You can then drag soundView around.
If you tap away from soundView frame, on the left-half of the screen, soundView will be animated out to the left and removed after animation completes.
If you tap away from soundView frame, on the right-half of the screen, soundView will be animated out to the right and removed after animation completes.
Once you've got that working, and you see what's happening, you can implement it in the rest of your much-more-complex code.
Edit
Take a look at this modified version of your code.
One big problem in your code is that you're making multiple calls to animatedHideSoundView(). When the drag gets near the edge, your code calls that... but then it gets called again because the drag is still "active."
So, I added a var isHideAnimationRunning: Bool flag so calls to positioning when dragging and positioning when "hide" animating don't conflict.
A few other changes:
instead of mixing Transforms with .center positioning, get rid of the Transforms and just use .center
I created a struct with logically named corner points - makes it much easier to reference them
strongly recommended: add comments to your code!
So, give this a try:
import UIKit
let screenWidth: CGFloat = UIScreen.main.bounds.width
let screenHeight: CGFloat = UIScreen.main.bounds.height
let sideSpacing: CGFloat = 32.0
let mediumSpacing: CGFloat = 16.0
var isNewIphone: Bool {
return screenHeight / screenWidth > 1.8
}
extension CGPoint {
func distance(to point: CGPoint) -> CGFloat {
return sqrt(pow(point.x - x, 2) + pow(point.y - y, 2))
}
}
// so we can refer to corner positions by logical names
struct CornerPoints {
var topLeft: CGPoint = .zero
var bottomLeft: CGPoint = .zero
var bottomRight: CGPoint = .zero
var topRight: CGPoint = .zero
}
final class ViewController: UIViewController {
private var cornerPoints = CornerPoints()
private let soundViewSide: CGFloat = 80.0
private lazy var halfSoundViewWidth = soundViewSide / 2
private lazy var newIphoneSpacing = isNewIphone ? mediumSpacing : 0.0
private lazy var soundView = SoundView(frame: CGRect(origin: .zero, size: CGSize(width: soundViewSide, height: soundViewSide)))
private lazy var notHiddenSoundViewRect = CGRect(x: mediumSpacing, y: 0.0, width: screenWidth - mediumSpacing * 2, height: screenHeight)
private var initialOffset: CGPoint = .zero
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .yellow
// setup corner points
let left = sideSpacing + halfSoundViewWidth
let right = view.frame.maxX - (sideSpacing + halfSoundViewWidth)
let top = sideSpacing + halfSoundViewWidth - newIphoneSpacing
let bottom = view.frame.maxY - (sideSpacing + halfSoundViewWidth - newIphoneSpacing)
cornerPoints.topLeft = CGPoint(x: left, y: top)
cornerPoints.bottomLeft = CGPoint(x: left, y: bottom)
cornerPoints.bottomRight = CGPoint(x: right, y: bottom)
cornerPoints.topRight = CGPoint(x: right, y: top)
let panGestureRecognizer = UIPanGestureRecognizer()
panGestureRecognizer.addTarget(self, action: #selector(soundViewPanned(recognizer:)))
soundView.addGestureRecognizer(panGestureRecognizer)
// for development, let's add a double-tap recognizer to
// add the soundView again (if it's been removed)
let dt = UITapGestureRecognizer(target: self, action: #selector(showAgain(_:)))
dt.numberOfTapsRequired = 2
view.addGestureRecognizer(dt)
DispatchQueue.main.asyncAfter(deadline: .now() + 1.0) {
self.animatedShowSoundView()
}
}
#objc func showAgain(_ f: UITapGestureRecognizer) {
// if soundView has been removed
if soundView.superview == nil {
// add it
animatedShowSoundView()
}
}
private func animatedShowSoundView() {
// start at bottom-right, off-screen to the right
let pt: CGPoint = cornerPoints.bottomRight
soundView.center = CGPoint(x: screenWidth + soundViewSide, y: pt.y)
view.addSubview(soundView)
soundView.startSoundBarsAnimation()
// animate to bottom-right corner
UIView.animate(withDuration: 0.5, delay: 0.0, options: .curveEaseOut) {
self.soundView.center = pt
}
}
// flag so we know if soundView is currently
// "hide" animating
var isHideAnimationRunning: Bool = false
private func animatedHideSoundView(toRight: Bool) {
// only execute if soundView is not currently "hide" animating
if !isHideAnimationRunning {
// set flag to true
isHideAnimationRunning = true
// target center X
let targetX: CGFloat = toRight ? screenWidth + soundViewSide : -soundViewSide
UIView.animate(withDuration: 0.5) {
self.soundView.center.x = targetX
} completion: { isFinished in
self.isHideAnimationRunning = false
if isFinished {
self.soundView.removeFromSuperview()
//self.songPlayer.pause()
}
}
}
}
#objc private func soundViewPanned(recognizer: UIPanGestureRecognizer) {
let touchPoint = recognizer.location(in: view)
switch recognizer.state {
case .began:
// only execute if soundView is not currently "hide" animating
if !isHideAnimationRunning {
initialOffset = CGPoint(x: touchPoint.x - soundView.center.x, y: touchPoint.y - soundView.center.y)
}
case .changed:
// only execute if soundView is not currently "hide" animating
if !isHideAnimationRunning {
soundView.center = CGPoint(x: touchPoint.x - initialOffset.x, y: touchPoint.y - initialOffset.y)
if notHiddenSoundViewRect.minX > soundView.frame.minX {
animatedHideSoundView(toRight: false)
} else if notHiddenSoundViewRect.maxX < soundView.frame.maxX {
animatedHideSoundView(toRight: true)
}
}
case .ended, .cancelled:
// only execute if soundView is not currently "hide" animating
if !isHideAnimationRunning {
let decelerationRate = UIScrollView.DecelerationRate.normal.rawValue
let velocity = recognizer.velocity(in: view)
let projectedPosition = CGPoint(
x: soundView.center.x + project(initialVelocity: velocity.x, decelerationRate: decelerationRate),
y: soundView.center.y + project(initialVelocity: velocity.y, decelerationRate: decelerationRate)
)
let nearestCornerPosition = nearestCorner(to: projectedPosition)
let relativeInitialVelocity = CGVector(
dx: relativeVelocity(forVelocity: velocity.x, from: soundView.center.x, to: nearestCornerPosition.x),
dy: relativeVelocity(forVelocity: velocity.y, from: soundView.center.y, to: nearestCornerPosition.y)
)
let timingParameters = UISpringTimingParameters(dampingRatio: 0.8, initialVelocity: relativeInitialVelocity)
let animator = UIViewPropertyAnimator(duration: 0.5, timingParameters: timingParameters)
animator.addAnimations {
self.soundView.center = nearestCornerPosition
}
animator.startAnimation()
}
default: break
}
}
private func project(initialVelocity: CGFloat, decelerationRate: CGFloat) -> CGFloat {
return (initialVelocity / 1000) * decelerationRate / (1 - decelerationRate)
}
private func nearestCorner(to point: CGPoint) -> CGPoint {
var minDistance = CGFloat.greatestFiniteMagnitude
var nearestPosition = CGPoint.zero
for position in [cornerPoints.topLeft, cornerPoints.bottomLeft, cornerPoints.bottomRight, cornerPoints.topRight] {
let distance = point.distance(to: position)
if distance < minDistance {
nearestPosition = position
minDistance = distance
}
}
return nearestPosition
}
/// Calculates the relative velocity needed for the initial velocity of the animation.
private func relativeVelocity(forVelocity velocity: CGFloat, from currentValue: CGFloat, to targetValue: CGFloat) -> CGFloat {
guard currentValue - targetValue != 0 else { return 0 }
return velocity / (targetValue - currentValue)
}
}

Running swift condition just once on translation

I created a UIView and a UIImageView which is inside the UIView as a subview, then I added a pan gesture to the UIImageView to slide within the UIView, the image slides now but the problem I have now is when the slider gets to the end of the view if movex > xMax, I want to print this just once print("SWIPPERD movex"). The current code I have there continues to print print("SWIPPERD movex") as long as the user does not remove his/her hand from the UIImageView which is used to slide
private func swipeFunc() {
let swipeGesture = UIPanGestureRecognizer(target: self, action: #selector(acknowledgeSwiped(sender:)))
sliderImage.addGestureRecognizer(swipeGesture)
swipeGesture.delegate = self as? UIGestureRecognizerDelegate
}
#objc func acknowledgeSwiped(sender: UIPanGestureRecognizer) {
if let sliderView = sender.view {
let translation = sender.translation(in: self.baseView) //self.sliderView
switch sender.state {
case .began:
startingFrame = sliderImage.frame
viewCenter = baseView.center
fallthrough
case .changed:
if let startFrame = startingFrame {
var movex = translation.x
if movex < -startFrame.origin.x {
movex = -startFrame.origin.x
print("SWIPPERD minmax")
}
let xMax = self.baseView.frame.width - startFrame.origin.x - startFrame.width - 15 //self.sliderView
if movex > xMax {
movex = xMax
print("SWIPPERD movex")
}
var movey = translation.y
if movey < -startFrame.origin.y { movey = -startFrame.origin.y }
let yMax = self.baseView.frame.height - startFrame.origin.y - startFrame.height //self.sliderView
if movey > yMax {
movey = yMax
// print("SWIPPERD min")
}
sliderView.transform = CGAffineTransform(translationX: movex, y: movey)
}
default: // .ended and others:
UIView.animate(withDuration: 0.1, animations: {
sliderView.transform = CGAffineTransform.identity
})
}
}
}
override func point(inside point: CGPoint, with event: UIEvent?) -> Bool {
return sliderImage.frame.contains(point)
}
You may want to use the .ended state instead of .changed state, based on your requirements. And you've mentioned you want to get the right direction only. You could try below to determine if the swipe came from right to left, or vice-versa, change as you wish:
let velocity = sender.velocity(in: sender.view)
let rightToLeftSwipe = velocity.x < 0

Using UIPanGestureRecognizer to swipe down UIView

I have an IBAction for a UIPanGestureRecognizer in my UIView, I am able to handle the gesture and recognise the state changes from began, cancelled and ended, as well as respond to those changes.
However when using the sender.location to handle the swipe down, the UIView actually moves up once the gesture has began, and then continues to move down. The experience is jarring and I am not sure what I am doing wrong. Does anybody have any ideas ?
func update(_ translation: CGPoint, origin: CGPoint) {
let offSetY = translation.y
cardView.frame.origin.y = offSetY
let multiplier = 1 - (translation.y / 2000)
self.view.alpha = multiplier
}
func cancel(_ origin: CGPoint) {
let animator = UIViewPropertyAnimator(duration: 0.6, dampingRatio: 0.6) {
self.visualEffectView.alpha = 1
self.cardView.alpha = 1.0
self.view.alpha = 1.0
self.cardView.center = origin
}
animator.startAnimation()
}
func finish() {
let animator = UIViewPropertyAnimator(duration: 0.9, dampingRatio: 0.9) {
self.visualEffectView.effect = nil
self.dismiss(animated: true, completion: nil)
}
animator.startAnimation()
}
#IBAction func panGestureAction(_ sender: UIPanGestureRecognizer) {
self.view.backgroundColor = .white
let originalCardPosition = cardView.center
//let cardOriginY = cardView.frame.origin.y
let translation = sender.translation(in: self.cardView)
let origin = sender.location(in: self.cardView)
switch sender.state {
case .changed:
if translation.y > 0 { update(translation, origin: origin) }
case .ended:
let translation = sender.translation(in: self.cardView)
if translation.y > 100 {
finish()
} else {
cardView.alpha = 1.0
cancel(originalCardPosition)
}
case .cancelled:
cancel(originalCardPosition)
default: break
}
}
The problem is that you set the origin.y of the cardView directly to the value of translation.y. You need to add translation.y to the view's original y value determined when the gesture begins.
Add a property to the class:
var originalY: CGFloat = 0
Then in the .began state of the gesture, set it:
originalY = cardView.frame.origin.y
Then in your update method you set the origin:
cardView.frame.origin.y = originalY + offSetY

UIKit Dynamics with pan, rotate and pinch gesture

I have added UIDynamics to imageview and used pan gesture for that. It is working fine with pan gesture but when I apply pinch gesture with that it is not working. It is showing large imageview but when I start dragging then it is changed to original size.
Here is my code:
func handleAttachmentGesture(_ sender: UIPanGestureRecognizer) {
let location = sender.location(in: emojiSuperView!)
let boxLocation = sender.location(in: self)
switch sender.state {
case .began:
print("Your touch start position is \(location)")
print("Start location in image is \(boxLocation)")
animator.removeAllBehaviors()
let centerOffset = UIOffset(horizontal: boxLocation.x - self.bounds.midX, vertical: boxLocation.y - self.bounds.midY)
attachmentBehavior = UIAttachmentBehavior(item: self, offsetFromCenter: centerOffset, attachedToAnchor: location)
animator.addBehavior(attachmentBehavior)
case .ended:
print("Your touch end position is \(location)")
print("End location in image is \(boxLocation)")
animator.removeAllBehaviors()
// 1
let velocity = sender.velocity(in: emojiSuperView!)
let magnitude = sqrt((velocity.x * velocity.x) + (velocity.y * velocity.y))
if magnitude > ThrowingThreshold {
// 2
let pushBehavior = UIPushBehavior(items: [self], mode: .instantaneous)
pushBehavior.pushDirection = CGVector(dx: velocity.x / 10, dy: velocity.y / 10)
pushBehavior.magnitude = magnitude / ThrowingVelocityPadding
self.pushBehavior = pushBehavior
animator.addBehavior(pushBehavior)
// 3
let angle = Int(arc4random_uniform(20)) - 10
itemBehavior = UIDynamicItemBehavior(items: [self])
itemBehavior.friction = 0.2
itemBehavior.allowsRotation = true
itemBehavior.addAngularVelocity(CGFloat(angle), for: self)
animator.addBehavior(itemBehavior)
}
default:
attachmentBehavior.anchorPoint = sender.location(in: emojiSuperView!)
break
}
}
func recognizePinchGesture(sender: UIPinchGestureRecognizer)
{
weak var dynamicItem: UIDynamicItem?
// whatever your item is, probably a UIView
dynamicItem = self
let behavior = UIGravityBehavior(items: [dynamicItem!])
let animator = UIDynamicAnimator(referenceView: emojiSuperView!)
// or however you're getting your animator
animator.addBehavior(behavior)
sender.view!.transform = sender.view!.transform.scaledBy(x: sender.scale, y: sender.scale)
animator.updateItem(usingCurrentState: self)
self.animator.updateItem(usingCurrentState: self)
sender.scale = 1
}
When a user does any transform event, save current transform to a global variable.
after that when panning start assigns new transform in began state using UIAttachmentBehavior's action property.
attachmentBehavior.action = {
self.attachmentBehavior.items[0].transform = self.aTransform
}

Rotating ImageView using UIPanGestureRecognizer- Swift 3

I am trying to rotate an ImageView I have depending on the X coordinate it is on. Basically, I want it to have a rotation of 0º when x = 300 and a rotation of 180º when x = 190.
I had to program the UIPanGestureRecognizer programmatically. Here is the code I currently have right now:
#objc func personDrag(recognizer: UIPanGestureRecognizer) {
let rotationSub: CGFloat = 1
let translation = recognizer.translation(in: rView)
if let view = recognizer.view {
view.center = CGPoint(x:view.center.x + translation.x, y:view.center.y + translation.y)
view.transform = view.transform.rotated(by: CGFloat.pi - rotationSub)
}
recognizer.setTranslation(CGPoint.zero, in: rView)
}
I was going to attempt to change the rotation degree by 1 every time they panned but it doesn't really work/make sense. Any help would be appreciated. Thank you so much!
Cheers, Theo
You can build your implementation on this:
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var imageview: UIImageView!
private var currentRotation: Rotation = .none
/* Certain rotation points (rotation of 0º when x = 300 and a rotation of 180º when x = 190) */
enum Rotation {
case none, xPoint190, xPoint300
}
override func viewDidLoad() {
super.viewDidLoad()
let gestureRecognizer = UIPanGestureRecognizer(target: self, action: #selector(handlePan))
imageview.addGestureRecognizer(gestureRecognizer)
imageview.isUserInteractionEnabled = true
}
#IBAction func handlePan(_ gestureRecognizer: UIPanGestureRecognizer) {
guard gestureRecognizer.state == .began || gestureRecognizer.state == .changed else {
return
}
guard let imgView = gestureRecognizer.view else {
return
}
let translation = gestureRecognizer.translation(in: self.view)
imgView.center = CGPoint(x: imgView.center.x + translation.x, y: imgView.center.y + translation.y)
gestureRecognizer.setTranslation(CGPoint.zero, in: self.view)
let angle: CGFloat = self.degreesToRadians(180.0)
/* After reaching x point case - rotating and setting rotation occured to prohibit further rotation */
if imgView.layer.frame.origin.x <= 190, currentRotation != .xPoint190 {
imgView.transform = imgView.transform.rotated(by: angle)
currentRotation = .xPoint190
} else if imgView.layer.frame.origin.x >= 300, currentRotation != .xPoint300 {
imgView.transform = imgView.transform.rotated(by: angle)
currentRotation = .xPoint300
}
private func degreesToRadians(_ deg: CGFloat) -> CGFloat {
return deg * CGFloat.pi / 180
}
}
I hope this will help you.
#objc func rotateViewPanGesture(_ recognizer: UIPanGestureRecognizer) {
touchLocation = recognizer.location(in: superview)
let center = CGRectGetCenter(frame)
switch recognizer.state {
case .began:
deltaAngle = atan2(touchLocation!.y - center.y, touchLocation!.x - center.x) - CGAffineTrasformGetAngle(transform)
initialBounds = bounds
initialDistance = CGpointGetDistance(center, point2: touchLocation!)
case .changed:
let ang = atan2(touchLocation!.y - center.y, touchLocation!.x - center.x)
let angleDiff = deltaAngle! - ang
let a = transform.a
let b = transform.b
let c = transform.c
let d = transform.d
let sx = sqrt(a * a + b * b)
let sy = sqrt(c * c + d * d)
let currentScale = CGPoint(x: sx, y: sy)
let scale = CGAffineTransform(scaleX: currentScale.x, y: currentScale.y)
self.transform = scale.rotated(by: -angleDiff)
layoutIfNeeded()
case .ended:
print("end gesture status")
default:break
}
}
Using Swift5
Programmatically
Rotate view by single point touch
import UIKit
class ViewController: UIViewController {
//Variable for rotating
private var deltaAngle:CGFloat = 0
let squareView : UIView = {
let anyView = UIView()
anyView.backgroundColor = .red
anyView.isUserInteractionEnabled = true
anyView.isMultipleTouchEnabled = true
return anyView
}()
let rotateButton : UIButton = {
let button = UIButton()
button.backgroundColor = .black
button.setImage(UIImage(systemName: "rotate.right"), for: .normal)
return button
}()
override func viewDidLoad() {
super.viewDidLoad()
squareView.frame = CGRect(x: 50, y: 50, width: 100, height: 100)
rotateButton.frame = CGRect(x: 0, y: squareView.frame.height-30, width: 30, height: 30)
squareView.center = view.center
view.addSubview(squareView)
squareView.addSubview(rotateButton)
let PanToRotate = UIPanGestureRecognizer(target: self, action: #selector(handleRotateGesture(_:)))
rotateButton.addGestureRecognizer(PanToRotate)
}
#objc func handleRotateGesture(_ recognizer : UIPanGestureRecognizer){
let touchLocation = recognizer.location(in: squareView.superview)
let center = squareView.center
switch recognizer.state{
case .began :
self.deltaAngle = atan2(touchLocation.y - center.y, touchLocation.x - center.x) - atan2(squareView.transform.b, squareView.transform.a)
case .changed:
let angle = atan2(touchLocation.y - center.y, touchLocation.x - center.x)
let angleDiff = self.deltaAngle - angle
squareView.transform = CGAffineTransform(rotationAngle: -angleDiff)
default: break
}
}
}

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