ios - 绘制的线条与触摸位置缩小并淡入背景 Swift 3.0
<p><p>我在 Swift 3.0 上遇到了一个奇怪的错误，我成功地绘制到位于 UIView 内的 UIImageView，但是当我绘制之前绘制的线开始淡入并缩小到 UIImageView 的顶部并变得非常模糊时如附图所示。
<a href="/image/DOKPU.png" rel="noreferrer noopener nofollow">Beginning of Drawing</a> , <a href="/image/rSWaP.png" rel="noreferrer noopener nofollow">Image becoming blurry</a> .</p>
<p>如果能提供任何帮助/指导，我将不胜感激。</p>
<pre><code>class DrawView: UIView {
var drawArea: UIImageView!
var clearDrawArea: UIButton!
var lastTouch = CGPoint.zero
init(){
super.init(frame: CGRect(x: UIScreen.main.bounds.width*0.135, y:UIScreen.main.bounds.height*0.05, width: UIScreen.main.bounds.width*0.8, height: UIScreen.main.bounds.height*0.9))
drawArea = UIImageView(frame: CGRect(x: self.frame.origin.x, y: self.frame.origin.y, width: self.bounds.width*0.9, height: self.bounds.height*0.86))
drawArea.backgroundColor = UIColor.white
let buttonWidth = self.bounds.width*0.2
let buttonHeight = self.bounds.height*0.1
clearDrawArea = UIButton(frame: CGRect(x: (self.bounds.width*0.61)-(buttonWidth/2), y: self.bounds.height*0.94, width: buttonWidth, height: buttonHeight))
clearDrawArea.setTitle("Clear Draw Area", for: .normal)
clearDrawArea.backgroundColor = UIColor(red: 49/255, green: 200/255, blue: 134/255, alpha: 255)
clearDrawArea.addTarget(self, action: #selector(resetImage), for: .touchUpInside)
self.addSubview(clearDrawArea)
self.addSubview(drawArea)
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
if let firstTouch = touches.first{
lastTouch = firstTouch.location(in: drawArea)
}
}
func drawLines(_ from: CGPoint, to: CGPoint){
UIGraphicsBeginImageContext(drawArea.frame.size)
let context = UIGraphicsGetCurrentContext()
context?.move(to: CGPoint(x: from.x, y: from.y))
context?.addLine(to: CGPoint(x: to.x, y: to.y))
context?.setLineCap(.round)
context?.setLineWidth(3)
context?.setStrokeColor(UIColor.black.cgColor)
context?.strokePath()
drawArea.image?.draw(in: drawArea.bounds)
drawArea.image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
if let firstTouch = touches.first{
let touchLocation = firstTouch.location(in: drawArea)
drawLines(lastTouch, to: touchLocation)
lastTouch = touchLocation
}
}
func resetImage(){
drawArea.image = nil
}
}
</code></pre></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>稍微修改一下你的代码试试下面的..</p>
<pre><code>class DrawView: UIView {
var drawArea: UIImageView!
var clearDrawArea: UIButton!
var lastTouch = CGPoint.zero
let pathAnimation: CABasicAnimation = CABasicAnimation(keyPath:"animation")
let tempPathLayer: CAShapeLayer = CAShapeLayer()
var lineLayer:CAShapeLayer=CAShapeLayer()
init(){
super.init(frame: CGRect(x: UIScreen.main.bounds.width*0.135, y:UIScreen.main.bounds.height*0.05, width: UIScreen.main.bounds.width*0.8, height: UIScreen.main.bounds.height*0.9))
drawArea = UIImageView(frame: CGRect(x: self.frame.origin.x, y: self.frame.origin.y, width: self.bounds.width*0.9, height: self.bounds.height*0.86))
drawArea.backgroundColor = UIColor.white
let buttonWidth = self.bounds.width*0.2
let buttonHeight = self.bounds.height*0.1
clearDrawArea = UIButton(frame: CGRect(x: (self.bounds.width*0.61)-(buttonWidth/2), y: self.bounds.height*0.94, width: buttonWidth, height: buttonHeight))
clearDrawArea.setTitle("Clear Draw Area", for: .normal)
clearDrawArea.backgroundColor = UIColor(red: 49/255, green: 200/255, blue: 134/255, alpha: 255)
clearDrawArea.addTarget(self, action: #selector(resetImage), for: .touchUpInside)
self.addSubview(clearDrawArea)
self.addSubview(drawArea)
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
//fatalError("init(coder:) has not been implemented")
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
if let firstTouch = touches.first{
lastTouch = firstTouch.location(in: drawArea)
}
}
func drawLines(_ from: CGPoint, to: CGPoint){
UIGraphicsBeginImageContext(drawArea.frame.size)
//let context = UIGraphicsGetCurrentContext()
let tempPath: UIBezierPath = UIBezierPath()
var lineLayer:CAShapeLayer=CAShapeLayer()
tempPath.move(to: from)
tempPath.addLine(to: to)
let strokeColor = UIColor.red
UIColor.blue.setFill()
strokeColor.setStroke()
let tempPathLayer: CAShapeLayer = CAShapeLayer()
tempPathLayer.frame = self.bounds
tempPathLayer.position=self.layer.position
tempPathLayer.strokeColor = UIColor.green.cgColor
tempPathLayer.fillColor = UIColor.red.cgColor
tempPathLayer.lineWidth = 1.0
tempPathLayer.path = tempPath.cgPath
lineLayer=tempPathLayer
pathAnimation.beginTime=CACurrentMediaTime()
pathAnimation.duration = 2
pathAnimation.fromValue = NSNumber(value: 0.0)
pathAnimation.toValue = NSNumber(value:1.0)
lineLayer.add(pathAnimation, forKey: "animation")
self.layer.addSublayer(lineLayer)
drawArea.image?.draw(in: drawArea.bounds)
drawArea.image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
if let firstTouch = touches.first{
let touchLocation = firstTouch.location(in: drawArea)
drawLines(lastTouch, to: touchLocation)
lastTouch = touchLocation
}
}
func resetImage(){
drawArea.image = nil
}
</code></pre>
<p>}</p></p>
<p style="font-size: 20px;">关于ios - 绘制的线条与触摸位置缩小并淡入背景 Swift 3.0，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/44253559/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/44253559/
</a>
</p>
页:
[1]