Draw a line on an NSWINDOW

Swift
1

Given X1,Y1, X2,Y2 that define the end points of a line
Draw said line on an NSWindow

  • Note : to the best of my knowlege you cannot draw a line DIRECTLY to the NSWindow, it must be draw within a NSView that is added to the window
  • so first the supplied coordinates must be converted to define a NSView
  • Then those must be further converted to be two points WITHIN the NSView
2

yep

the width would be max(x1, x2) - min(x1,x2)
height much the same

then offset the navies to the left = min(x1,x2) top = min(y1,y2)

then draw with the points internally offset y the left & top of the NSView

been there done this

3

Thanks… I arrived at basically the same answer :slight_smile:

4

figured you might

now draw a line inside and nsview that is inside another nsview :stuck_out_tongue:
it gets messy quickly but I suspect Swift has better facilities for dealing with the true location of such an deeply nested embedded view

5

in old version you can draw in nswindow now it’s forbidden

func drawLineOnWindow(_ window: NSWindow) {
guard let context = window.graphicsContext?.cgContext else {
print(“Failed to get CGContext”)
return
}

    // Begin drawing
    context.saveGState()
    
    context.setStrokeColor(NSColor.red.cgColor)
    context.setLineWidth(2.0)
    
    // Draw a line from (50, 50) to (350, 250)
    context.move(to: CGPoint(x: 50, y: 50))
    context.addLine(to: CGPoint(x: 350, y: 250))
    
    context.strokePath()
    context.restoreGState()
}
6

yeah that doesn’t work, and even if it did, it would not be applicable to this app, seeing as the coordiantes are not know until runtime, plus I need to have complete control of the z-order, where this method would draw the line(s) under everthing else on the window, but thanks

7

here is my solution… seems to work in all use cases :slight_smile:

open class uxLINE: ux$Shape {
    var pt1 = CGPoint.zero
    var pt2 = CGPoint.zero
    @MainActor required public init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    public override init(frame:CGRect=CGRect.zero) {
        let oldFrame = frame
        super.init(frame:CGRect(x:0,y:0,width:max(frame.origin.x,frame.size.width),height:max(frame.origin.y,frame.size.height)))
        pt1 = oldFrame.origin
        pt2 = CGPoint(x:oldFrame.size.width,y:oldFrame.size.height)
        constructor()
    }

  // MARK: OBJECT DECLARATION
    public override func draw(_ rect: CGRect) {
        // unlike other shapes, LINE uses CGRECT to store the line ENDS
        super.draw(rect)
        let context: CGContext = NSGraphicsContext.current!.cgContext
        context.setStrokeColor(lineColor.cgColor)
        context.setLineWidth(borderWidth)
        context.setLineDash(phase: 0,lengths: penStyle.mask)
        context.move(to: pt1)
        context.addLine(to: pt2)
        context.strokePath()
    }
}
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