SwiftyDraw

Overview

SwiftyDraw is a simple, light-weight drawing framework written in Swift. SwiftyDraw is built using Core Gaphics and is very easy to implement.

Requirements

• iOS 9.1+
• Swift 4

License

SwiftyDraw is available under the BSD license. See the LICENSE file for more info.

Installation

Cocoapods:

SwiftyDraw is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod 'SwiftyDraw'

Manual Installation:

Simply copy the contents of the Source folder into your project.

Usage

Using SwiftyDraw is very simple:

Getting Started:

Simply create a SwiftyDrawView and add it to your View Controller:

let drawView = SwiftyDrawView(frame: self.view.frame)
self.view.addSubview(drawView)

By default, the view will automatically respond to touch gestures and begin drawing. The default color is black.

To disable drawing, simply set the isEnabled property to false:

drawView.isEnabled = false

Brushes

For drawing, we use Brush to keep track of styles like width, color, etc.. We have multiple different default brushes, you can use as follows:

drawView.brush = Brush.default

The default brushed are:

public static var `default`: Brush { get } // black, width 3
public static var thin     : Brush { get } // black, width 2
public static var medium   : Brush { get } // black, width 7
public static var thick    : Brush { get } // black, width 10
public static var marker   : Brush { get } // flat red-ish, width 12
public static var eraser   : Brush { get } // white, width 8; currently this fakes an eraser by using the canvas' background color to draw

Adjusted Width Factor

SwiftyDrawView supports drawing-angle-adjusted brushes. Effectively, that means, if the user (using an Pencil) draws with the tip of the pencil, the brush will reduce its width a little. If the user draws at a very low angle, with the side of the pencil, the brush will be a little thicker. You can modify this behavior by setting adjustedWidthFactor of a brush. If you increase the number (to, say, 5) the changes will increase. If you reduce the number to 0, the width will not be adjusted at all. The default value is 1 which causes a slight increase in width.

This is an opt-in feature. That means, in shouldBeginDrawingIn, you need to manually put drawingView.brush.adjustWidth(for: touch), to make it work. That is, because you might not want to use it if you have implemented a zoom feature and want to disable it while the user is zooming to get better results.

Further Customization:

For more customization, you can modify the different properties of a brush to fit your needs.

Line Color:

The color of a line stroke can be changed by adjusting the color property of a brush. SwiftyDraw accepts any UIColor:

drawView.brush.color = .red

or

drawView.brush.color = UIColor(colorLiteralRed: 0.75, green: 0.50, blue: 0.88, alpha: 1.0)

Line Width:

The width of a line stroke can be changed by adjusting the width property of a brush. SwiftyDraw accepts any positive CGFloat:

drawView.brush.width = CGFloat(5.0)

Line Opacity:

The opacity of a line stroke can be changed by adjusting the lineOpacity property. SwiftyDraw accepts a CGFloat between 0. and 1.0:

drawView.brush.opacity = CGFloat(0.5)

Editing

Clear All:

If you wish to clear the entire canvas, simply call the clear function:

drawView.clear()

Drawing History:

drawView.undo()

...and redo:

drawView.redo()

Delegate

SwiftyDraw has delegate functions to notify you when a user is interacting with a SwiftDrawView. To access these delegate methods, simply make your View Controller conform to the SwiftyDrawViewDelegate protocol:

class ViewController: UIViewController, SwiftyDrawViewDelegate

There are five delegate methods

/// SwiftyDrawViewDelegate called when a touch gesture should begin on the SwiftyDrawView using given touch type
func swiftyDraw(shouldBeginDrawingIn drawingView: SwiftyDrawView, using touch: UITouch) -> Bool
    
/// SwiftyDrawViewDelegate called when a touch gesture begins on the SwiftyDrawView.
func swiftyDraw(didBeginDrawingIn drawingView: SwiftyDrawView, using touch: UITouch)

/// SwiftyDrawViewDelegate called when touch gestures continue on the SwiftyDrawView.
func swiftyDraw(isDrawingIn drawingView: SwiftyDrawView, using touch: UITouch)
    
/// SwiftyDrawViewDelegate called when touches gestures finish on the SwiftyDrawView.
func swiftyDraw(didFinishDrawingIn drawingView: SwiftyDrawView, using touch: UITouch)
    
/// SwiftyDrawViewDelegate called when there is an issue registering touch gestures on the  SwiftyDrawView.
func swiftyDraw(didCancelDrawingIn drawingView: SwiftyDrawView, using touch: UITouch)

Contribution

This is a project built by Awalz and maintained & improved by LinusGeffarth.

If you would like to propose any enhancements, bug fixes, etc., feel free to create a pull request or an issue respectively.

Contact

If you have any questions, or just want to say hi, you can reach out to me via Twitter, or email.