Running swift condition just once on translation - ios

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

Related

iOS Swift: Rotate and Scale UIView without resizing

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
}
}

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

Dragging UIView

I need some help with dragging UIView to reveal, menu view underneath main view.
I have two UIViews.
menuView - includes menu buttons and labels
and mainView - located over menuView.
I want to drag the main view from left edge to show menu items and snap the main view to a specific position. I am able to get the dragging to the right working but I cannot set it back to original position when dragging left.
here is my codes I have been playing around with but no success.
I also wanted to make mainView smaller as I drag it to right.
any help will be greatly appreciated.
Note: PanGesture is attached to mainView.
#IBAction func dragMenu(_ sender: UIPanGestureRecognizer) {
let mview = sender.view!
let originalCenter = CGPoint(x: self.mainView.bounds.width/2, y: self.mainView.bounds.height/2)
switch sender.state {
case .changed:
if let mview = sender.view {
mview.center.x = mview.center.x + sender.translation(in: view).x
sender.setTranslation(CGPoint.zero, in: view)
}
case .ended:
let DraggedHalfWayRight = mview.center.x > view.center.x
if DraggedHalfWayRight {
//dragginToRight
showMenu = !showMenu
self.mainViewRight.constant = 200
self.mainTop.constant = 50
self.mainBottom.constant = 50
self.mainLeft.constant = 200
} else //dragging left and set it back to original position.
{
mview.center = originalCenter
showMenu = !showMenu
}
default:
break
}
}
I'd suggest a few things:
When you're done dragging the menu off, make sure to set its alpha to zero (so that, if you were in portrait and go to landscape, you don't suddenly see the menu sitting there).
I personally just adjust the transform of the dragged view and avoid resetting the translation of the gesture back to zero all the time. That's a matter of personal preference.
I'd make the view controller the delegate for the gesture and implement gestureRecognizerShouldBegin (because if the menu is hidden, you don't want to recognize swipes to try to hide it again; and if it's not hidden, you don't want to recognize swipes to show it).
When figuring out whether to complete the gesture or not, I also consider the velocity of the gesture (e.g. so a little flick will dismiss/show the animated view).
Thus:
class ViewController: UIViewController {
#IBOutlet weak var menuView: UIView!
var isMenuVisible = true
#IBAction func dragMenu(_ gesture: UIPanGestureRecognizer) {
let translationX = gesture.translation(in: gesture.view!).x
switch gesture.state {
case .began:
// if the menu is not visible, make sure it's off screen and then make it visible
if !isMenuVisible {
menuView.transform = CGAffineTransform(translationX: gesture.view!.bounds.width, y: 0)
menuView.alpha = 1
}
fallthrough
case .changed:
if isMenuVisible {
menuView.transform = CGAffineTransform(translationX: translationX, y: 0)
} else {
menuView.transform = CGAffineTransform(translationX: gesture.view!.bounds.width + translationX, y: 0)
}
case .ended:
let shouldComplete: Bool
if isMenuVisible {
shouldComplete = translationX > gesture.view!.bounds.width / 2 || gesture.velocity(in: gesture.view!).x > 0
} else {
shouldComplete = -translationX > gesture.view!.bounds.width / 2 || gesture.velocity(in: gesture.view!).x < 0
}
UIView.animate(withDuration: 0.25, animations: {
if self.isMenuVisible && shouldComplete || !self.isMenuVisible && !shouldComplete {
self.menuView.transform = CGAffineTransform(translationX: gesture.view!.bounds.width, y: 0)
} else {
self.menuView.transform = .identity
}
if shouldComplete{
self.isMenuVisible = !self.isMenuVisible
}
}, completion: { _ in
self.menuView.alpha = self.isMenuVisible ? 1 : 0
})
default:
break
}
}
}
extension ViewController: UIGestureRecognizerDelegate {
func gestureRecognizerShouldBegin(_ gesture: UIGestureRecognizer) -> Bool {
guard let gesture = gesture as? UIPanGestureRecognizer else { return true }
let translationX = gesture.translation(in: gesture.view!).x
return isMenuVisible && translationX > 0 || !isMenuVisible && translationX < 0
}
}
Personally, I prefer to use a separate screen edge gesture recognizer to pull them menu back on screen (you don't really want it to recognize gestures anywhere, but just on that right edge). Another virtue of this approach is that by keeping "show" and "hide" in different functions, the code is a lot more readable (IMHO):
class ViewController: UIViewController {
#IBOutlet weak var menuView: UIView!
var isMenuVisible = true
#IBAction func handleScreenEdgeGesture(_ gesture: UIScreenEdgePanGestureRecognizer) {
let translationX = gesture.translation(in: gesture.view!).x
switch gesture.state {
case .began:
menuView.transform = CGAffineTransform(translationX: gesture.view!.bounds.width, y: 0)
menuView.alpha = 1
fallthrough
case .changed:
menuView.transform = CGAffineTransform(translationX: gesture.view!.bounds.width + translationX, y: 0)
case .ended:
let shouldComplete = -translationX > gesture.view!.bounds.width / 2 || gesture.velocity(in: gesture.view!).x < 0
UIView.animate(withDuration: 0.25, delay:0, options: .curveEaseOut, animations: {
if shouldComplete {
self.menuView.transform = .identity
self.isMenuVisible = !self.isMenuVisible
} else {
self.menuView.transform = CGAffineTransform(translationX: gesture.view!.bounds.width, y: 0)
}
}, completion: { _ in
self.menuView.alpha = self.isMenuVisible ? 1 : 0
})
default:
break
}
}
#IBAction func dragMenu(_ gesture: UIPanGestureRecognizer) {
let translationX = gesture.translation(in: gesture.view!).x
switch gesture.state {
case .began, .changed:
menuView.transform = CGAffineTransform(translationX: translationX, y: 0)
case .ended:
let shouldComplete = translationX > gesture.view!.bounds.width / 2 || gesture.velocity(in: gesture.view!).x > 0
UIView.animate(withDuration: 0.25, delay:0, options: .curveEaseOut, animations: {
if shouldComplete {
self.menuView.transform = CGAffineTransform(translationX: gesture.view!.bounds.width, y: 0)
self.isMenuVisible = !self.isMenuVisible
} else {
self.menuView.transform = .identity
}
}, completion: { _ in
self.menuView.alpha = self.isMenuVisible ? 1 : 0
})
default:
break
}
}
}
extension ViewController: UIGestureRecognizerDelegate {
func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
if gestureRecognizer is UIScreenEdgePanGestureRecognizer {
return !isMenuVisible
} else if let gesture = gestureRecognizer as? UIPanGestureRecognizer {
let translationX = gesture.translation(in: gesture.view!).x
return isMenuVisible && translationX > 0
}
return true
}
}

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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