Drawsana

Drawsana is a generalized framework for making freehand drawing views on iOS. You can let users scribble over images, add shapes and text, and even make your own tools.

Do you want to let your users mark up images? Are you writing a simple painting app? Drawsana might work for you!

Demo source code

Docs

Features

• Built-in tools
  • Pen with line smoothing
  • Eraser
  • Ellipse, rect, line, arrow
  • Selection
  • Text
• Undo/redo
• Drawings are Codable, so you can save and load them
• Extensible—make your own shapes and tools without forking the library

Installation

Add Asana/Drawsana to your Cartfile and update your project like you would for any other Carthage framework, or clone the source code and add the project to your workspace.

Usage

import Drawsana

class MyViewController: UIViewController {
  let drawsanaView = DrawsanaView()
  
  func viewDidLoad() {
    /* ... */
    drawsanaView.set(tool: PenTool())
    drawsanaView.userSettings.strokeWidth = 5
    drawsanaView.userSettings.strokeColor = .blue
    drawsanaView.userSettings.fillColor = .yellow
    drawsanaView.userSettings.fontSize = 24
    drawsanaView.userSettings.fontName = "Marker Felt"
  }
  
  func save() {
    let jsonEncoder = JSONEncoder()
    jsonEncoder.outputFormatting = [.prettyPrinted, .sortedKeys]
    let jsonData = try! jsonEncoder.encode(drawingView.drawing)
    // store jsonData somewhere
  }
  
  func load() {
    let data = // load data from somewhere
    let jsonDecoder = JSONDecoder()
    let drawing = try! jsonDecoder.decode(Drawing.self, from: jsonData)
    drawsanaView.drawing = drawing
  }
  
  func showFinalImage() {
    imageView.image = drawsanaView.render() 
  }
}

Background images

Drawsana does not currently have a way to automatically show an image under your drawing. We recommend that, like in the example class, you add a UIImageView underneath your DrawsanaView and make sure your DrawsanaView's frame matches the image frame. When it's time to get the final image, use DrawsanaView.render(over: myImage).

Building docs

sudo gem install jazzy
make docs
open .docs/index.html

pip install ghp-import
make publish-docs
open https://asana.github.io/Drawsana