SwiftSignatureView (now with PencilKit!)

Description

SwiftSignatureView is a lightweight, fast and customizable option for capturing signatures within your app. You can retrieve the signature as a UIImage. With code that varies the pen width based on the speed of the finger movement, the view generates fluid, natural looking signatures. And now, with iOS13+, SwiftSignatureView automatically uses PencilKit to provide a native and even more fluid signature experience, including a natural integration with the Apple Pencil which makes SwiftSignatureView even better!

Version 3.2.0

WARNING: This update changes the SwiftSignatureViewDelegate interface. Use the swiftSignatureViewDidDrawGesture to receive gesture events. In PencilKit (iOS13+) you get an additional swiftSignatureViewDidDraw event when the user ends a drawing sequence with the tool they were using.
Added Undo/Redo.
Added isEmpty to determine if the signature canvas is empty.
Fixed the constraints of the demo app.
Views and canvas are configured internally only using constraint layout.
Swiftlint fixes applied.
Added a page sheet version explaining how to use the library purely by code.
Added crop function for the PencilKit version (with resolution of the signature sorted).

Version 3.0.0

SwiftSignatureView now uses PencilKit for iOS13+ to provide a native and even more fluid signature experience, including a natural integration with the Apple Pencil.

Known issues

Currently the getCroppedSignature method won't work as expected with iOS13+ and instead returns the uncropped image.

Version 2.2.3 | Swift 5.0

SwiftSignatureView now draws from the point of touch instead of the point from where the pan gesture was recognized.

Version 2.2.2 | Swift 5.0

Modified the swiftSignatureViewDidPanInside delegate method to include the pan gesture recognizer in the callback. Warning: This will change the interface!

Version 2.2.0 | Swift 5.0

Added a getCroppedSignature method to get a UIImage of the signature with surrounding whitespace trimmed
Made the signature image publicly settable
Modified the example to demonstrate the cropped signature function

[ A big thank you to all the contributors. I know I don't say it enough. ]

Version 2.1.0 | Swift 5.0

Updated the Pod to Swift 5.0 syntax. The interface remains unchanged.

Version 2.0 | Swift 3.0 / XCode 8

Upgraded the Pod to Swift 3.0 syntax. The interface remains unchanged.

Version 1.0.3 | Swift 2.3 / XCode 8 compatibility

Upgraded the Example to use XCode 8 Storyboards. The SwiftSignatureView class file, however, remains unchanged when 'upgraded' to Swift 2.3.

Version 1.0.2 | Callbacks for panning/tapping

Added delegate for callbacks on panning/tapping.

Version 1.0.1 | Bug fixes and Syntax updates to Swift 2.2

Fixes an issue where the signature might appear blurred on retina displays
Updates the syntax to Swift 2.2
Fixes pod spec to make it compatible with Cocoapods 1.0

Version 0.0.8 | Bug fixes

Version 0.0.8 fixes a bug that caused SwiftSignatureView to compute incorrect offsets when not in full-screen mode. A big thank you to Todd Kersey for discovering the bug and suggesting a fix. This update fixes the issue.

Usage

To run the example project, clone the repo, and run pod install from the Example directory first.

More specifically, you simply assign the SwiftSignatureView class to a UIView, optionally play with the minimum stroke width, maximum stroke width, stroke color and stroke alpha all which are settable from within the Interface Builder itself and you're all set! You can then use the signature property to get a UIImage representation of the signature and the clear method to clear the signature view. For example if you had:

@IBOutlet weak var signatureView: SwiftSignatureView!

you can use

signatureView.signature()

to get a UIImage representation of the signature;

signatureView.getCroppedSignature()

to get a UIImage representation of the cropped signature with the surrounding whitespace trimmed.

signatureView.clear()

to clear the signature view.

Installation

SwiftSignatureView is available through CocoaPods and Swift Package Manager.

For Cocoapods >= 1.0

Add the following lines to your Podfile:

use_frameworks!
target "YOUR_PROJECT_NAME" do
    pod "SwiftSignatureView"
end

For Cocoapods < 1.0