swift - 使用swift功能自动更新NSView

我有一个带有一些绘图的自定义NSView：

class ViewController: NSViewController {

@IBOutlet weak var mainView: LineDrawer!
var time = NSTimer()
override func viewDidLoad() {
    super.viewDidLoad()
    self.view.needsDisplay = true
    // Do any additional setup after loading the view.
}

override var representedObject: AnyObject? {
    didSet {
        // Update the view, if already loaded.
    }
}


}


class LineDrawer : NSView {
required init?(coder  aDecoder : NSCoder) {
    super.init(coder: aDecoder)
}

var lastPt : CGPoint!
var newPt : CGPoint!
var tmp = CGPoint()
override func viewWillDraw() {
    super.viewWillDraw()
    lastPt = newPt
}

override func drawRect(dirtyRect: NSRect) {
    super.drawRect(dirtyRect)
    self.needsDisplay = true
    NSColor.redColor().set()
    var newLinear = NSBezierPath()
    newLinear.moveToPoint(NSMakePoint(newPt.x, newPt.y))
    newLinear.lineToPoint(NSMakePoint(tmp.x, tmp.y))
    newLinear.lineWidth = 1
    newLinear.stroke()
    println(1)
}

override func mouseDown(theEvent: NSEvent) {
    super.mouseDown(theEvent)
    let location = theEvent.locationInWindow
    lastPt = theEvent.locationInWindow
    tmp = lastPt
}

override func mouseDragged(theEvent: NSEvent) {
    super.mouseDragged(theEvent)
    newPt = theEvent.locationInWindow
    self.drawRect(self.frame)
    tmp = newPt

}

}

它可以工作，但只有在隐藏并使窗口返回后，才会出现线条。我正在寻找在updateTheView函数中编写的代码，以便在每次激活mouseDragged时更新视图

最佳答案

您需要将NSBezierstroke放到drawRect中，而不是mouseDragged中。将mouseDragged中的坐标保存在一个实例数组中，然后使用drawRect中的Bezier进行最终绘制。
drawRect在视图需要显示时由操作系统调用（无论是从某个地方被needsDisplay = true告知，还是当窗口被移动时）。在鼠标移动程序中只存储路径。然后当涉及到绘图时drawRect将实际画出这条线。

class LineDrawer : NSView {
  var newLinear = NSBezierPath()

  override func drawRect(dirtyRect: NSRect) {
    NSColor.redColor().set()
    newLinear.lineWidth = 1
    newLinear.stroke()
  }

  override func mouseDown(theEvent: NSEvent) {
    super.mouseDown(theEvent)
    let location = theEvent.locationInWindow
    var lastPt = theEvent.locationInWindow
    lastPt.x -= frame.origin.x
    lastPt.y -= frame.origin.y
    newLinear.moveToPoint(lastPt)
  }

  override func mouseDragged(theEvent: NSEvent) {
    super.mouseDragged(theEvent)
    var newPt = theEvent.locationInWindow
    newPt.x -= frame.origin.x
    newPt.y -= frame.origin.y
    newLinear.lineToPoint(newPt)
    needsDisplay = true
  }
}

我在一个窗户里用一个清晰的视角测试了它。

关于swift - 使用swift功能自动更新NSView，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/28239705/