good_bad_access.swift

    public override func draw(_ dirtyRect: NSRect) {
        for location in Int(dirtyRect.origin.x)..<Int(dirtyRect.origin.x + dirtyRect.size.width) {
            let colorBox = NSBezierPath(rect: NSRect(x: CGFloat(location), y:0, width: 2.0, height: self.bounds.size.height))
            
            var alpha: CGFloat = 1.0
            if location < drawValues.count {
                let locationPower = drawValues[location]
                guard let locationmax = drawValues.max() else {
                    fatalError()
                }
                if locationmax == 0 {
                    alpha = 0
                } else {
                    alpha = CGFloat(locationPower / locationmax)
                }
                
                alpha = alpha < minimumAlpha ? minimumAlpha : alpha
            }
            
            var color = colorData[location] ?? NSColor(calibratedRed: 0.75, green: 0.75, blue: 0.75, alpha: 1.0)
            
            color = NSColor(calibratedRed: color.redComponent, green: color.greenComponent, blue: color.blueComponent, alpha: alpha)
            color.setFill()
            colorBox.fill()
        }
    }