Drawing selection box (rubberbanding, marching ants) in Cocoa, ObjectiveC

Question

I\'ve currently implemented a simple selection box using mouse events and redrawing a rectangle on mouse drag. Here\'s my code:

-(void)drawRect:(NSRect)dirty         


        

Answer 1

If anybody needs a Swift 2.0 version, here it is:

import Cocoa
import QuartzCore


class myView: NSView {

var startPoint : NSPoint!
var shapeLayer : CAShapeLayer!



override func drawRect(dirtyRect: NSRect) {
    super.drawRect(dirtyRect)

    // Drawing code here.
}


override func mouseDown(theEvent: NSEvent) {

    self.startPoint = self.convertPoint(theEvent.locationInWindow, fromView: nil)

    shapeLayer = CAShapeLayer()
    shapeLayer.lineWidth = 1.0
    shapeLayer.fillColor = NSColor.clearColor().CGColor
    shapeLayer.strokeColor = NSColor.blackColor().CGColor
    shapeLayer.lineDashPattern = [10,5]
    self.layer?.addSublayer(shapeLayer)

    var dashAnimation = CABasicAnimation()
    dashAnimation = CABasicAnimation(keyPath: "lineDashPhase")
    dashAnimation.duration = 0.75
    dashAnimation.fromValue = 0.0
    dashAnimation.toValue = 15.0
    dashAnimation.repeatCount = .infinity
    shapeLayer.addAnimation(dashAnimation, forKey: "linePhase")




}

override func mouseDragged(theEvent: NSEvent) {

    let point : NSPoint = self.convertPoint(theEvent.locationInWindow, fromView: nil)
    let path = CGPathCreateMutable()
    CGPathMoveToPoint(path, nil, self.startPoint.x, self.startPoint.y)
    CGPathAddLineToPoint(path, nil, self.startPoint.x, point.y)
    CGPathAddLineToPoint(path, nil, point.x, point.y)
    CGPathAddLineToPoint(path, nil, point.x, self.startPoint.y)
    CGPathCloseSubpath(path)
    self.shapeLayer.path = path
}

override func mouseUp(theEvent: NSEvent) {
    self.shapeLayer.removeFromSuperlayer()
    self.shapeLayer = nil
}



}