Browse Author: Swarupa Doiphode

Implement a drawing app in Swift

Implement smooth drawing in iOS using swift.

A drawing app allows the user to draw on the screen with their finger. There are many companies  ask customers to sign on apple device when making purchases. 


1> create a custom class line for initializing values of start and end point of line

import UIKit

class Line{

  var start : CGPoint

  var end : CGPoint

  init(start _start : CGPoint , end _end : CGPoint) {

    start = _start

    end = _end



2> We will create a custom drawview UIView class.  for drawing line from start and end point using draw function,   So that it can act like a canvas for our drawing app.  

import UIKit

class DrawView: UIView {

  var lines : [Line] = []

  var lastPoint : CGPoint!

  required init(coder aDecoder : NSCoder) {

    super.init(coder: aDecoder)!


  override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {

    lastPoint = touches.first?.location(in: self)


  override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {

    let newPoint = touches.first?.location(in: self)

    lines.append(Line(start: lastPoint, end: newPoint!))

    lastPoint = newPoint




  override func draw(_ rect: CGRect) {

    var context = UIGraphicsGetCurrentContext()


    for line in lines


      let aPath = UIBezierPath()

      aPath.lineWidth = 5.0

      aPath.lineJoinStyle = .round

      aPath.move(to: CGPoint(x:line.start.x,y:line.start.y))

      aPath.addLine(to: CGPoint(x:line.end.x,y:line.end.y))


      aPath.lineCapStyle = .round





3> write controller class in which we are using the draw view class for drawing line

import UIKit

class ViewController: UIViewController {

  @IBOutlet var drawView : AnyObject!

  override func viewDidLoad() {


    // Do any additional setup after loading the view, typically from a nib.


  override func didReceiveMemoryWarning() {


    // Dispose of any resources that can be recreated.


@IBAction func clearbutton()


  let theDrawView : DrawView = drawView as! DrawView

  theDrawView.lines = []




Happy Drawing

Download PDF file using Alamofire in Swift3

Almofire is a very popular library for networking related coding(eg. API call, Downloading Stuffs etc) and totally developed in swift which is replacement of AFNetworking library of ObjectiveC. It has multiple features like Image cacheing, API call integration,File downloading etc. Today we are going to dive into Download PDF file using Alamofire in Swift.

Pods are available for almofire on GitHub for integration of this library into your own project, some steps are explained as follows:- 

  • First create a pod file for implementing the Alamofire and MBProgressHUD

pod ‘Alamofire’ // Download PDF file
pod ‘MBProgressHUD’ //Downloading Progress Bar

  • We have to create Webview Object for open downloaded PDF url.
  • Use following function in view controller and pass the url string to the function.


 func downloadPDFFile(urlString:String)


    let hud = MBProgressHUD.showAdded(to: self.view, animated: true)

    hud.mode = MBProgressHUDMode.annularDeterminate

    hud.label.text = “Loading…”


    let destination: DownloadRequest.DownloadFileDestination = { _, _ in

      let documentsURL:NSURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first! as    NSURL

      print(“***documentURL: “,documentsURL)

      let PDF_name : String = “Downloded_PDF_Name”

      let fileURL = documentsURL.appendingPathComponent(PDF_name)

      print(“***fileURL: “,fileURL ?? “”)

       return (fileURL!,[.removePreviousFile, .createIntermediateDirectories])

    }, to: destination).downloadProgress(closure: { (prog) in

      hud.progress = Float(prog.fractionCompleted)

    }).response { response in


      hud.hide(animated: true)

      if response.error == nil, let filePath = response.destinationURL?.path    {

        print(“File Path”,filePath)


        //Open this filepath in Webview Object


        let fileURL = URL(fileURLWithPath: filePath)

        let request = URLRequest(url: fileURL)





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