A grid view in swift, can be shown in a iOS camera app. It draws three rows and three columns which helps user to take a picture precisely.

GridView.swift

class GridView: UIView {
    
// Only override draw() if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
override func draw(_ rect: CGRect) {
    
    // Drawing code
    
    let borderLayer = gridLayer()
    borderLayer.path = UIBezierPath(rect: bounds).cgPath
    layer.addSublayer(borderLayer)
    
    let firstColumnPath = UIBezierPath()
    firstColumnPath.move(to: CGPoint(x: bounds.width / 3, y: 0))
    firstColumnPath.addLine(to: CGPoint(x: bounds.width / 3, y: bounds.height))
    let firstColumnLayer = gridLayer()
    firstColumnLayer.path = firstColumnPath.cgPath
    layer.addSublayer(firstColumnLayer)
    
    let secondColumnPath = UIBezierPath()
    secondColumnPath.move(to: CGPoint(x: (2 * bounds.width) / 3, y: 0))
    secondColumnPath.addLine(to: CGPoint(x: (2 * bounds.width) / 3, y: bounds.height))
    let secondColumnLayer = gridLayer()
    secondColumnLayer.path = secondColumnPath.cgPath
    layer.addSublayer(secondColumnLayer)
    
    let firstRowPath = UIBezierPath()
    firstRowPath.move(to: CGPoint(x: 0, y: bounds.height / 3))
    firstRowPath.addLine(to: CGPoint(x: bounds.width, y: bounds.height / 3))
    let firstRowLayer = gridLayer()
    firstRowLayer.path = firstRowPath.cgPath
    layer.addSublayer(firstRowLayer)
    
    let secondRowPath = UIBezierPath()
    secondRowPath.move(to: CGPoint(x: 0, y: ( 2 * bounds.height) / 3))
    secondRowPath.addLine(to: CGPoint(x: bounds.width, y: ( 2 * bounds.height) / 3))
    let secondRowLayer = gridLayer()
    secondRowLayer.path = secondRowPath.cgPath
    layer.addSublayer(secondRowLayer)
}
private func gridLayer() -> CAShapeLayer {
    let shapeLayer = CAShapeLayer()
    shapeLayer.strokeColor = UIColor.white.cgColor
    shapeLayer.lineDashPattern = [3, 3]
    shapeLayer.frame = bounds
    shapeLayer.fillColor = nil
    return shapeLayer
}
}

Below is its usage and how to add grid view at run time.

private func addGridView() {
    // cameraView is your view where you want to show the grid view
    let horizontalMargin = cameraView.bounds.size.width / 4
    let verticalMargin = cameraView.bounds.size.height / 4
    
    let gridView = GridView()
    gridView.translatesAutoresizingMaskIntoConstraints = false
    cameraView.addSubview(gridView)
    gridView.backgroundColor = UIColor.clear
    gridView.leftAnchor.constraint(equalTo: cameraView.leftAnchor, constant: horizontalMargin).isActive = true
    gridView.rightAnchor.constraint(equalTo: cameraView.rightAnchor, constant: -1 * horizontalMargin).isActive = true
    gridView.topAnchor.constraint(equalTo: cameraView.topAnchor, constant: verticalMargin).isActive = true
    gridView.bottomAnchor.constraint(equalTo: cameraView.bottomAnchor, constant: -1 * verticalMargin).isActive = true
}

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