通过按下圆角上的圆圈并拖动它使其变小/变大来调整 ImageView 的大小
[英]Resize ImageView by pressing on a circle on it's corner and dragging it to make it smaller/bigger
问题描述
我一直在做这个包含 UIImageView 的小应用程序。我可以点击它，图像的每个角上应该会出现 4 个圆圈。 我必须能够从角落拖动手指来调整图像大小。 但是调整大小不起作用。 据我了解-我必须在touchesMoved方法中更新 imageView 的约束。
我正在使用这篇文章作为参考： How to resize UIView by dragging from its edges?
设置 imageView，scrollView 和按钮
struct ResizeRect{
var topTouch = false
var leftTouch = false
var rightTouch = false
var bottomTouch = false
var middelTouch = false
}
这是我在角落里的圈子
private var topLeftCircleLayer: CAShapeLayer!
private var topRightCircleLayer: CAShapeLayer!
private var bottomLeftCircleLayer: CAShapeLayer!
private var bottomRightCircleLayer: CAShapeLayer!
imageView 的约束条件
private var imageViewTopConstraint: NSLayoutConstraint!
private var imageViewBottomConstraint: NSLayoutConstraint!
private var imageViewLeadingConstraint: NSLayoutConstraint!
private var imageViewTrailingConstraint: NSLayoutConstraint!
private var originalImageFrame: CGRect = .zero
private var resizeRect = ResizeRect()
设置我的视图
override func viewDidLoad() {
super.viewDidLoad()
scrollView.delegate = self
setupView()
addTapGestureRecognizer()
addPinchGestureRecognizer()
addRotateButton()
addDeletePhotoButton()
}
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
borderLayer.path = UIBezierPath(rect: imageView.bounds).cgPath
addConstraintsForItems()
createCircles()
}
private func addConstraintsForItems() {
imageViewTopConstraint = imageView.topAnchor.constraint(equalTo: view.topAnchor, constant: 180)
imageViewBottomConstraint = imageView.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: -180)
imageViewLeadingConstraint = imageView.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 70)
imageViewTrailingConstraint = imageView.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -70)
NSLayoutConstraint.activate([imageViewTopConstraint, imageViewBottomConstraint, imageViewLeadingConstraint, imageViewTrailingConstraint])
}
private func setupView() {
view.addSubview(scrollView)
view.addSubview(rotateButton)
view.addSubview(deleteButton)
scrollView.addSubview(imageView)
borderLayer.fillColor = UIColor.clear.cgColor
borderLayer.strokeColor = UIColor.black.cgColor
borderLayer.lineWidth = 2
borderLayer.isHidden = true
imageView.layer.addSublayer(borderLayer)
}
圈子创建
private func updateCircles() {
let topLeft = CGPoint(x: imageView.frame.minX, y: imageView.frame.minY)
topLeftCircleLayer.position = topLeft
let topRight = CGPoint(x: imageView.frame.maxX, y: imageView.frame.minY)
topRightCircleLayer.position = topRight
let bottomLeft = CGPoint(x: imageView.frame.minX, y: imageView.frame.maxY)
bottomLeftCircleLayer.position = bottomLeft
let bottomRight = CGPoint(x: imageView.frame.maxX, y: imageView.frame.maxY)
bottomRightCircleLayer.position = bottomRight
imageView.layer.insertSublayer(topLeftCircleLayer, at: 0)
imageView.layer.insertSublayer(topRightCircleLayer, at: 1)
imageView.layer.insertSublayer(bottomLeftCircleLayer, at: 2)
imageView.layer.insertSublayer(bottomRightCircleLayer, at: 3)
}
private func createCircles() {
topLeftCircleLayer = createCircle(at: CGPoint(x: imageView.frame.minX, y: imageView.frame.minY))
topRightCircleLayer = createCircle(at: CGPoint(x: imageView.frame.maxX, y: imageView.frame.minY))
bottomLeftCircleLayer = createCircle(at: CGPoint(x: imageView.frame.minX, y: imageView.frame.maxY))
bottomRightCircleLayer = createCircle(at: CGPoint(x: imageView.frame.maxX, y: imageView.frame.maxY))
}
private func createCircle(at position: CGPoint) -> CAShapeLayer {
let circle = CAShapeLayer()
circle.path = UIBezierPath(arcCenter: position, radius: 10, startAngle: 0, endAngle: .pi * 2, clockwise: true).cgPath
circle.fillColor = UIColor.systemPink.cgColor
circle.strokeColor = UIColor.white.cgColor
circle.lineWidth = 6
circle.isHidden = !isCirclesVisible
imageView.layer.addSublayer(circle)
return circle
}
这是我尝试拖动角落的最重要部分
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
if let touch = touches.first{
let touchStart = touch.location(in: self.view)
print(touchStart)
resizeRect.topTouch = false
resizeRect.leftTouch = false
resizeRect.rightTouch = false
resizeRect.bottomTouch = false
if touchStart.y > imageView.frame.maxY - proxyFactor && touchStart.y < imageView.frame.maxY + proxyFactor {
resizeRect.bottomTouch = true
print("bottom")
}
if touchStart.x > imageView.frame.maxX - proxyFactor && touchStart.x < imageView.frame.maxX + proxyFactor {
resizeRect.rightTouch = true
print("right")
}
if touchStart.x > imageView.frame.minX - proxyFactor && touchStart.x < imageView.frame.minX + proxyFactor {
resizeRect.leftTouch = true
print("left")
}
if touchStart.y > imageView.frame.minY - proxyFactor && touchStart.y < imageView.frame.minY + proxyFactor {
resizeRect.topTouch = true
print("top")
}
}
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
if let touch = touches.first{
let currentTouchPoint = touch.location(in: self.view)
let previousTouchPoint = touch.previousLocation(in: self.view)
let deltaX = currentTouchPoint.x - previousTouchPoint.x
let deltaY = currentTouchPoint.y - previousTouchPoint.y
if resizeRect.topTouch && resizeRect.leftTouch {
if imageViewTopConstraint.constant + deltaY > 0 && imageViewLeadingConstraint.constant + deltaX > 0 {
imageViewTopConstraint.constant += deltaY
imageViewLeadingConstraint.constant += deltaX
}
}
if resizeRect.topTouch && resizeRect.rightTouch {
if imageViewTopConstraint.constant + deltaY > 0 && imageViewTrailingConstraint.constant - deltaX > 0 {
imageViewTopConstraint.constant += deltaY
imageViewTrailingConstraint.constant -= deltaX
}
}
if resizeRect.bottomTouch && resizeRect.leftTouch {
if imageViewBottomConstraint.constant - deltaY > 0 && imageViewLeadingConstraint.constant + deltaX > 0 {
imageViewLeadingConstraint.constant += deltaX
imageViewBottomConstraint.constant -= deltaY
}
}
if resizeRect.bottomTouch && resizeRect.rightTouch {
if imageViewBottomConstraint.constant - deltaY > 0 && imageViewTrailingConstraint.constant - deltaX > 0 {
imageViewTrailingConstraint.constant -= deltaX
imageViewBottomConstraint.constant -= deltaY
}
}
UIView.animate(withDuration: 0.25, delay: 0, options: UIView.AnimationOptions.curveEaseIn) {
self.view.layoutIfNeeded()
}
}
}
编辑 1：我稍微更新了我的代码。 当我触摸 imageView 时，我的应用程序终于明白了，当我触摸一个角时，它可以说出哪个角被触摸了，但调整大小无法正常工作。 有时它可以工作，但调整大小的速度非常慢。 在控制台中它说我有这个错误：
Probably at least one of the constraints in the following list is one you don't want.
Try this:
(1) look at each constraint and try to figure out which you don't expect;
(2) find the code that added the unwanted constraint or constraints and fix it.
(
"<NSLayoutConstraint:0x600000cf8910 H:|-(65)-[UIImageView:0x13a707300] (active, names: '|':UIView:0x13c20f220 )>",
"<NSLayoutConstraint:0x600000ce0640 H:|-(70)-[UIImageView:0x13a707300] (active, names: '|':UIView:0x13c20f220 )>"
)
Will attempt to recover by breaking constraint
<NSLayoutConstraint:0x600000ce0640 H:|-(70)-[UIImageView:0x13a707300] (active, names: '|':UIView:0x13c20f220 )>
我尝试更新约束，但出于某种原因它不允许我这样做。 我从一个编写解决方案的人那里克隆了 github 项目。 他制作了 IBOutlets 用于约束，据我所知 - 从 IBOutlets 创建的约束与我拥有的约束有些不同。 如何解决约束问题？ 如果有人能注意到我创建的圈子有什么问题，我将不胜感激。 现在我只看到图像中间下方的 1 ...
1 个解决方案
解决方案1
0 已采纳 2023-01-23 16:06:21
你的方法有几个问题......
首先，这些都不是：
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
borderLayer.path = UIBezierPath(rect: imageView.bounds).cgPath
addConstraintsForItems()
createCircles()
}
应该在那里。 viewDidLayoutSubviews()被多次调用，如果您正在更改视图/约束，它将被调用多次。
其次，您可能无法让 GitHub 项目使用代码设置（与使用@IBOutlet连接的 Storyboard 设置相反）是因为约束的顺序颠倒了。
在您的代码中，您在 imageView 上设置了所有 4 个约束，从imageView -> view开始。 可以像这样复制 Storyboard 设置：
// top and leading constraints need to be imageView -> view
imageViewTopConstraint = imageView.topAnchor.constraint(equalTo: view.topAnchor, constant: 180)
imageViewLeadingConstraint = imageView.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 70)
// trailing and bottom constraints need to be view -> imageView
imageViewTrailingConstraint = view.trailingAnchor.constraint(equalTo: imageView.trailingAnchor, constant: 70)
imageViewBottomConstraint = view.bottomAnchor.constraint(equalTo: imageView.bottomAnchor, constant: 180)
第三，您在某些需要使用.frame的地方使用.bounds 。
这是您的代码的修改版本。 我不知道你是如何决定何时显示/隐藏圆角的，所以我添加了一个双击手势来激活/停用“调整大小”模式：
class ResizeViewViewController: UIViewController {
private var topLeftCircleLayer: CAShapeLayer!
private var topRightCircleLayer: CAShapeLayer!
private var bottomLeftCircleLayer: CAShapeLayer!
private var bottomRightCircleLayer: CAShapeLayer!
private var borderLayer: CAShapeLayer!
private var imageViewTopConstraint: NSLayoutConstraint!
private var imageViewBottomConstraint: NSLayoutConstraint!
private var imageViewLeadingConstraint: NSLayoutConstraint!
private var imageViewTrailingConstraint: NSLayoutConstraint!
private var originalImageFrame: CGRect = .zero
private var resizeRect = ResizeRect()
private var proxyFactor: CGFloat = 10.0
private var imageView = UIImageView()
private var isResizing: Bool = false {
didSet {
// update circle positions and
// show or hide the circles and border
updateCircles()
topLeftCircleLayer.isHidden = !isResizing
topRightCircleLayer.isHidden = !isResizing
bottomLeftCircleLayer.isHidden = !isResizing
bottomRightCircleLayer.isHidden = !isResizing
borderLayer.isHidden = !isResizing
}
}
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = UIColor(white: 0.9, alpha: 1.0)
setupView()
addConstraintsForItems()
createCircles()
isResizing = false
// let's use double-tap on the image view to
// toggle resizing
let t = UITapGestureRecognizer(target: self, action: #selector(gotDoubleTap(_:)))
t.numberOfTapsRequired = 2
imageView.addGestureRecognizer(t)
imageView.isUserInteractionEnabled = true
// an instructions label at the top
let v = UILabel()
v.textAlignment = .center
v.text = "Double-Tap image to toggle resizing mode."
v.translatesAutoresizingMaskIntoConstraints = false
// put it under the image view so it doesn't interfere
view.insertSubview(v, at: 0)
NSLayoutConstraint.activate([
v.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 20.0),
v.centerXAnchor.constraint(equalTo: view.safeAreaLayoutGuide.centerXAnchor),
])
}
@objc func gotDoubleTap(_ sender: Any?) {
isResizing.toggle()
}
private func addConstraintsForItems() {
// top and leading constraints need to be imageView -> view
imageViewTopConstraint = imageView.topAnchor.constraint(equalTo: view.topAnchor, constant: 180)
imageViewLeadingConstraint = imageView.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 70)
// trailing and bottom constraints need to be view -> imageView
imageViewTrailingConstraint = view.trailingAnchor.constraint(equalTo: imageView.trailingAnchor, constant: 70)
imageViewBottomConstraint = view.bottomAnchor.constraint(equalTo: imageView.bottomAnchor, constant: 180)
NSLayoutConstraint.activate([
imageViewTopConstraint, imageViewBottomConstraint, imageViewLeadingConstraint, imageViewTrailingConstraint
])
}
private func setupView() {
// add the image view
imageView.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(imageView)
imageView.backgroundColor = .systemYellow
// let's use the "swift" SF Symbol image
if let img = UIImage(systemName: "swift") {
imageView.image = img
imageView.tintColor = .systemBlue
}
borderLayer = CAShapeLayer()
borderLayer.fillColor = UIColor.clear.cgColor
borderLayer.strokeColor = UIColor.black.cgColor
borderLayer.lineWidth = 2
borderLayer.isHidden = true
imageView.layer.addSublayer(borderLayer)
}
private func updateCircles() {
// we need to disable CALayer internal animations when
// changing the positions of the layers
CATransaction.begin()
CATransaction.setDisableActions(true)
let topLeft = CGPoint(x: imageView.bounds.minX, y: imageView.bounds.minY)
topLeftCircleLayer.position = topLeft
let topRight = CGPoint(x: imageView.bounds.maxX, y: imageView.bounds.minY)
topRightCircleLayer.position = topRight
let bottomLeft = CGPoint(x: imageView.bounds.minX, y: imageView.bounds.maxY)
bottomLeftCircleLayer.position = bottomLeft
let bottomRight = CGPoint(x: imageView.bounds.maxX, y: imageView.bounds.maxY)
bottomRightCircleLayer.position = bottomRight
borderLayer.path = UIBezierPath(rect: imageView.bounds).cgPath
CATransaction.commit()
}
private func createCircles() {
// no need to pass "positions" here... they will be set when we show / update them
topLeftCircleLayer = createCircle()
topRightCircleLayer = createCircle()
bottomLeftCircleLayer = createCircle()
bottomRightCircleLayer = createCircle()
// add the layers here
imageView.layer.addSublayer(topLeftCircleLayer)
imageView.layer.addSublayer(topRightCircleLayer)
imageView.layer.addSublayer(bottomLeftCircleLayer)
imageView.layer.addSublayer(bottomRightCircleLayer)
}
private func createCircle() -> CAShapeLayer {
let circle = CAShapeLayer()
circle.path = UIBezierPath(arcCenter: .zero, radius: 10, startAngle: 0, endAngle: .pi * 2, clockwise: true).cgPath
circle.fillColor = UIColor.systemPink.cgColor
circle.strokeColor = UIColor.white.cgColor
circle.lineWidth = 6
circle.isHidden = true
return circle
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
if !isResizing { return() }
if let touch = touches.first{
let touchStart = touch.location(in: self.view)
print(touchStart, imageView.frame)
resizeRect.topTouch = false
resizeRect.leftTouch = false
resizeRect.rightTouch = false
resizeRect.bottomTouch = false
if touchStart.y > imageView.frame.maxY - proxyFactor && touchStart.y < imageView.frame.maxY + proxyFactor {
resizeRect.bottomTouch = true
print("bottom")
}
if touchStart.x > imageView.frame.maxX - proxyFactor && touchStart.x < imageView.frame.maxX + proxyFactor {
resizeRect.rightTouch = true
print("right")
}
if touchStart.x > imageView.frame.minX - proxyFactor && touchStart.x < imageView.frame.minX + proxyFactor {
resizeRect.leftTouch = true
print("left")
}
if touchStart.y > imageView.frame.minY - proxyFactor && touchStart.y < imageView.frame.minY + proxyFactor {
resizeRect.topTouch = true
print("top")
}
}
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
if !isResizing { return() }
if let touch = touches.first{
let currentTouchPoint = touch.location(in: self.view)
let previousTouchPoint = touch.previousLocation(in: self.view)
let deltaX = currentTouchPoint.x - previousTouchPoint.x
let deltaY = currentTouchPoint.y - previousTouchPoint.y
if resizeRect.topTouch {
imageViewTopConstraint.constant += deltaY
}
if resizeRect.leftTouch {
imageViewLeadingConstraint.constant += deltaX
}
if resizeRect.rightTouch {
imageViewTrailingConstraint.constant -= deltaX
}
if resizeRect.bottomTouch {
imageViewBottomConstraint.constant -= deltaY
}
// don't know why you would want to animate this?
//UIView.animate(withDuration: 0.25, delay: 0, options: UIView.AnimationOptions.curveEaseIn, animations: {
// self.view.layoutIfNeeded()
//}, completion: { (ended) in
//
//})
// note: this can "lag" and not precisely match the image view frame
self.updateCircles()
// we can dispatch it async to allow UIKit to set the
// image view's frame before we move the layers
// but we still get a little "lag"
DispatchQueue.main.async {
self.updateCircles()
}
}
}
}
struct ResizeRect{
var topTouch = false
var leftTouch = false
var rightTouch = false
var bottomTouch = false
var middelTouch = false
}
当您运行它时，您会注意到在拖动和调整大小时存在一些“滞后”——请参阅代码中的注释。
一种类似的方法可能会发现它的响应速度更快，并且更易于管理……
我们将添加“圆形视图”作为图像视图的子视图，而不是添加“圆形图层”。 然后我们可以对图像视图角设置约束，并让自动布局处理所有定位。
更少的代码……利用自动布局……更灵敏……
首先运行上面的版本，然后试试这个：
class CircleView: UIView {
// this allows us to use the "base" layer as a shape layer
// instead of adding a sublayer
lazy var shapeLayer: CAShapeLayer = self.layer as! CAShapeLayer
override class var layerClass: AnyClass {
return CAShapeLayer.self
}
override init(frame: CGRect) {
super.init(frame: frame)
commonInit()
}
required init?(coder: NSCoder) {
super.init(coder: coder)
commonInit()
}
func commonInit() {
shapeLayer.fillColor = UIColor.systemPink.cgColor
shapeLayer.strokeColor = UIColor.white.cgColor
shapeLayer.lineWidth = 6
}
override func layoutSubviews() {
super.layoutSubviews()
shapeLayer.path = UIBezierPath(ovalIn: bounds).cgPath
}
}
class ResizeViewViewController: UIViewController {
private var topLeftCircleView = CircleView()
private var topRightCircleView = CircleView()
private var bottomLeftCircleView = CircleView()
private var bottomRightCircleView = CircleView()
private var borderView = UIView()
private var imageViewTopConstraint: NSLayoutConstraint!
private var imageViewBottomConstraint: NSLayoutConstraint!
private var imageViewLeadingConstraint: NSLayoutConstraint!
private var imageViewTrailingConstraint: NSLayoutConstraint!
private var originalImageFrame: CGRect = .zero
private var resizeRect = ResizeRect()
private var proxyFactor: CGFloat = 10.0
private var imageView = UIImageView()
private var isResizing: Bool = false {
didSet {
// show or hide the circles and image view border
[topLeftCircleView, topRightCircleView, bottomLeftCircleView, bottomRightCircleView].forEach { v in
v.isHidden = !isResizing
}
borderView.layer.borderWidth = isResizing ? 2.0 : 0.0
}
}
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = UIColor(white: 0.9, alpha: 1.0)
setupView()
addConstraintsForItems()
createCircles()
isResizing = false
// let's use double-tap on the image view to
// toggle resizing
let t = UITapGestureRecognizer(target: self, action: #selector(gotDoubleTap(_:)))
t.numberOfTapsRequired = 2
imageView.addGestureRecognizer(t)
imageView.isUserInteractionEnabled = true
// an instructions label at the top
let v = UILabel()
v.textAlignment = .center
v.text = "Double-Tap image to toggle resizing mode."
v.font = .systemFont(ofSize: 15.0, weight: .light)
v.translatesAutoresizingMaskIntoConstraints = false
// put it under the image view so it doesn't interfere
view.insertSubview(v, at: 0)
NSLayoutConstraint.activate([
v.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 20.0),
v.centerXAnchor.constraint(equalTo: view.safeAreaLayoutGuide.centerXAnchor),
])
}
@objc func gotDoubleTap(_ sender: Any?) {
isResizing.toggle()
}
private func addConstraintsForItems() {
// top and leading constraints need to be imageView -> view
imageViewTopConstraint = imageView.topAnchor.constraint(equalTo: view.topAnchor, constant: 180)
imageViewLeadingConstraint = imageView.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 70)
// trailing and bottom constraints need to be view -> imageView
imageViewTrailingConstraint = view.trailingAnchor.constraint(equalTo: imageView.trailingAnchor, constant: 70)
imageViewBottomConstraint = view.bottomAnchor.constraint(equalTo: imageView.bottomAnchor, constant: 180)
NSLayoutConstraint.activate([
imageViewTopConstraint, imageViewBottomConstraint, imageViewLeadingConstraint, imageViewTrailingConstraint,
// constrain all 4 sides of the borderView to the imageView
borderView.topAnchor.constraint(equalTo: imageView.topAnchor),
borderView.leadingAnchor.constraint(equalTo: imageView.leadingAnchor),
borderView.trailingAnchor.constraint(equalTo: imageView.trailingAnchor),
borderView.bottomAnchor.constraint(equalTo: imageView.bottomAnchor),
])
}
private func setupView() {
// add the image view
imageView.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(imageView)
imageView.backgroundColor = .systemYellow
// add the borderView to the image view
// we'd like to just use the image view's layer border, but
// setting its border width draws on top of the circle subviews
borderView.translatesAutoresizingMaskIntoConstraints = false
imageView.addSubview(borderView)
// let's use the "swift" SF Symbol image
if let img = UIImage(systemName: "swift") {
imageView.image = img
imageView.tintColor = .systemBlue
}
// border view layer border starts at width: 0 (not showing)
borderView.layer.borderColor = UIColor.black.cgColor
borderView.layer.borderWidth = 0
}
private func createCircles() {
// add the circle views to the image view
// constraining width: 20 and height = width
[topLeftCircleView, topRightCircleView, bottomLeftCircleView, bottomRightCircleView].forEach { v in
v.translatesAutoresizingMaskIntoConstraints = false
v.widthAnchor.constraint(equalToConstant: 20.0).isActive = true
v.heightAnchor.constraint(equalTo: v.widthAnchor).isActive = true
// they start hidden
v.isHidden = true
imageView.addSubview(v)
}
// constrain circleViews to the image view corners
NSLayoutConstraint.activate([
topLeftCircleView.centerXAnchor.constraint(equalTo: imageView.leadingAnchor),
topLeftCircleView.centerYAnchor.constraint(equalTo: imageView.topAnchor),
topRightCircleView.centerXAnchor.constraint(equalTo: imageView.trailingAnchor),
topRightCircleView.centerYAnchor.constraint(equalTo: imageView.topAnchor),
bottomLeftCircleView.centerXAnchor.constraint(equalTo: imageView.leadingAnchor),
bottomLeftCircleView.centerYAnchor.constraint(equalTo: imageView.bottomAnchor),
bottomRightCircleView.centerXAnchor.constraint(equalTo: imageView.trailingAnchor),
bottomRightCircleView.centerYAnchor.constraint(equalTo: imageView.bottomAnchor),
])
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
// only want to drag-resize if the corner circles are showing
if !isResizing { return() }
if let touch = touches.first{
let touchStart = touch.location(in: self.view)
print(touchStart, imageView.frame)
resizeRect.topTouch = false
resizeRect.leftTouch = false
resizeRect.rightTouch = false
resizeRect.bottomTouch = false
if touchStart.y > imageView.frame.maxY - proxyFactor && touchStart.y < imageView.frame.maxY + proxyFactor {
resizeRect.bottomTouch = true
print("bottom")
}
if touchStart.x > imageView.frame.maxX - proxyFactor && touchStart.x < imageView.frame.maxX + proxyFactor {
resizeRect.rightTouch = true
print("right")
}
if touchStart.x > imageView.frame.minX - proxyFactor && touchStart.x < imageView.frame.minX + proxyFactor {
resizeRect.leftTouch = true
print("left")
}
if touchStart.y > imageView.frame.minY - proxyFactor && touchStart.y < imageView.frame.minY + proxyFactor {
resizeRect.topTouch = true
print("top")
}
}
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
// only want to drag-resize if the corner circles are showing
if !isResizing { return() }
if let touch = touches.first{
let currentTouchPoint = touch.location(in: self.view)
let previousTouchPoint = touch.previousLocation(in: self.view)
let deltaX = currentTouchPoint.x - previousTouchPoint.x
let deltaY = currentTouchPoint.y - previousTouchPoint.y
if resizeRect.topTouch {
imageViewTopConstraint.constant += deltaY
}
if resizeRect.leftTouch {
imageViewLeadingConstraint.constant += deltaX
}
if resizeRect.rightTouch {
imageViewTrailingConstraint.constant -= deltaX
}
if resizeRect.bottomTouch {
imageViewBottomConstraint.constant -= deltaY
}
// don't know why you would want to animate this?
//UIView.animate(withDuration: 0.25, delay: 0, options: UIView.AnimationOptions.curveEaseIn, animations: {
// self.view.layoutIfNeeded()
//}, completion: { (ended) in
//
//})
}
}
}
struct ResizeRect{
var topTouch = false
var leftTouch = false
var rightTouch = false
var bottomTouch = false
var middelTouch = false
}
动画UIView的蒙版（将较大的圆圈CAShapeLayer缩小）
[英]Animating a UIView's mask (larger circle CAShapeLayer to smaller)
Swift 如何将UIStackView放置在特定的角落 ImageView
[英]Swift How to Place UIStackView in a Specific Corner of ImageView
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