我正在尝试制作一个可以顺着手指在屏幕上绘制的应用程序。我从几个网站上收集了资料,并设法完成了。 screenshot app screen
该应用程序正在运行,我可以选择不同的颜色,并且线条沿我的手指延伸。唯一的事情是,当我在一排线后在真实设备(iPhone SE和Xs Max)上使用它时,我的应用程序崩溃并显示消息iOS终止在内存中。 模拟器不会发生这种情况。我没有足够的经验来使用乐器。知道是什么原因造成的吗?
函数可能有问题:
func drawLineFrom(fromPoint: CGPoint, toPoint: CGPoint) {
或者iPhone的内存不足以在全屏上绘制,那么我在浪费时间寻找没有解决方案的解决方案吗?
import UIKit
class ViewController: UIViewController {
@IBOutlet weak var UIImage: UIImageView!
@IBOutlet weak var tempImageView: UIImageView!
@IBOutlet weak var colourInUse: UILabel!
var lastPoint = CGPoint.zero
var red: CGFloat = 0.0
var green: CGFloat = 0.0
var blue: CGFloat = 0.0
var brushWidth: CGFloat = 2.0
var opacity: CGFloat = 1.0
var swiped = false
let colors: [(CGFloat, CGFloat, CGFloat)] = [
(0, 0, 0),
(105.0 / 255.0, 105.0 / 255.0, 105.0 / 255.0),
(1.0, 0, 0),
(0, 0, 1.0),
(51.0 / 255.0, 204.0 / 255.0, 1.0),
(102.0 / 255.0, 204.0 / 255.0, 0),
(102.0 / 255.0, 1.0, 0),
(160.0 / 255.0, 82.0 / 255.0, 45.0 / 255.0),
(1.0, 102.0 / 255.0, 0),
(1.0, 1.0, 0),
(1.0, 1.0, 1.0),
]
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
UIImage.isUserInteractionEnabled = true
tempImageView.isUserInteractionEnabled = true
colourInUse.text = "Black"
}
@IBAction func pencilPressed(sender: AnyObject) {
var index = sender.tag ?? 0
if index < 0 || index >= colors.count {
index = 0
}
(red, green, blue) = colors[index]
if index == colors.count - 1 {
opacity = 1.0
}
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
swiped = false
if let touch = touches.first {
lastPoint = touch.location(in: self.view)
}
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
swiped = true
if let touch = touches.first {
let currentPoint = touch.location(in: view)
drawLineFrom(fromPoint: lastPoint, toPoint: currentPoint)
lastPoint = currentPoint
}
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
if !swiped {
drawLineFrom(fromPoint: lastPoint, toPoint: lastPoint)
}
// Merge tempImageView into mainImageView
UIGraphicsBeginImageContext(UIImage.frame.size)
UIImage.image?.draw(in: CGRect(x: 0, y: 0, width: view.frame.size.width, height: view.frame.size.height), blendMode: CGBlendMode.normal, alpha: 1.0)
tempImageView.image?.draw(in: CGRect(x: 0, y: 0, width: view.frame.size.width, height: view.frame.size.height), blendMode: CGBlendMode.normal, alpha: opacity)
UIImage.image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
tempImageView.image = nil
}
func drawLineFrom(fromPoint: CGPoint, toPoint: CGPoint) {
UIGraphicsBeginImageContext(view.frame.size)
UIGraphicsBeginImageContextWithOptions(view.frame.size, false, 0)
let drawContext = UIGraphicsGetCurrentContext()
tempImageView.image?.draw(in: CGRect(x: 0, y: 0, width: view.frame.size.width, height: view.frame.size.height))
drawContext?.move(to: CGPoint(x: fromPoint.x, y: fromPoint.y))
drawContext?.addLine(to: CGPoint(x: toPoint.x, y: toPoint.y))
drawContext?.setLineCap(CGLineCap.round)
drawContext?.setLineWidth(brushWidth)
drawContext?.setStrokeColor(red: red, green: green, blue: blue, alpha: 1.0)
drawContext?.setBlendMode(CGBlendMode.normal)
drawContext?.strokePath()
tempImageView.image = UIGraphicsGetImageFromCurrentImageContext()
tempImageView.alpha = opacity
UIGraphicsEndImageContext()
}
}