SwiftHaptics

SwiftHaptics is a cross-platform Swift package to provide advanced haptics using a simple yet powerful API.

Installation

Add https://github.com/jochenbernard/swift-haptics to your project using Swift Package Manager.

Usage

Playing Basic Haptic Patterns

Haptic patterns can easily be triggered from your SwiftUI views using the haptics view modifier. You can provide haptics with an Equatable trigger and a HapticPattern or a HapticPatternBuilder. The haptic pattern will be played when the provided trigger value changes.

var body: some View {
    someView
        .haptics(trigger: trigger) {
            TransientHapticEvent(time: 0.0)

            ContinuousHapticEvent(
                time: 0.5,
                duration: 0.5
            )
        }
}

Creating Advanced Haptic Patterns

SwiftHaptics provides two basic haptic events which are the building blocks to create haptic patterns: TransientHapticEvent and ContinuousHapticEvent. Transient events are brief impulses while continuous events are looped waveforms of arbitrary length.

Using these two basic haptic events you can create custom, more advanced, haptic patterns by conforming to the HapticPattern protocol. A HapticPattern has to define a pattern property, which is a HapticPatternBuilder, to provide its underlying pattern. These builders also support if statements, switch statements and for loops.

struct MyHapticPattern: HapticPattern {
    var pattern: HapticPattern {
        TransientHapticEvent(time: 0.0)

        ContinuousHapticEvent(
            time: 0.5,
            duration: 0.5
        )
    }
}

Modifying Haptic Patterns

Haptic patterns also support modifiers.

• scale allows you to scale a haptic pattern's intensity and sharpness.
• speed allows you to speed up or slow down a haptic pattern.
• delay allows you to delay a haptic pattern.
• muted allows you to conditionally mute a haptic pattern.

var body: some View {
    someView
        .haptics(trigger: trigger) {
            MyHapticPattern()
                .scale(
                    intensity: 0.5,
                    sharpness: 2.0
                )
                .speed(2.0)
                .delay(1.0)
                .muted(!playHaptics)
        }
}

Creating Custom Haptic Pattern Modifiers

You can also implement custom haptic pattern modifiers by conforming to the HapticPatternModifier protocol. A HapticPatternModifier has to define a pattern function, which is a HapticPatternBuilder, that receives the original HapticPattern and returns the modified HapticPattern.

To apply a HapticPatternModifier to a HapticPattern use the modifier function.

struct MyHapticPatternModifier: HapticPatternModifier {
    func pattern(pattern: HapticPattern) -> HapticPattern {
        pattern
            .scale(
                intensity: 2.0,
                sharpness: 2.0
            )
            .speed(2.0)
    }
}

extension HapticPattern {
    func myModifier() -> HapticPattern {
        modifier(MyHapticPatternModifier())
    }
}

Next, the custom modifier can be used as follows:

MyHapticPattern()
    .myModifier()

Playing Haptic Patterns Outside Of SwiftUI

SwiftHaptics can also be used outside of SwiftUI by creating a HapticEngine instance and using its play method. You can provide play with either a HapticPattern or a HapticPatternBuilder.

let hapticEngine = HapticEngine()
hapticEngine.play {
    TransientHapticEvent(time: 0.0)

    ContinuousHapticEvent(
        time: 0.5,
        duration: 0.5
    )
}