FDWaveformView

FDWaveformView displays audio waveforms in Swift apps so users can preview audio, scrub, and pick positions with ease.

Usage

Add an FDWaveformView programmatically, then load audio. If your file is missing an extension, see the Stack Overflow answer on AVURLAsset without extensions.

let thisBundle = Bundle(for: type(of: self))
let url = thisBundle.url(forResource: "Submarine", withExtension: "aiff")
self.waveform.audioURL = url

Features

Highlight playback

Highlight a portion of the waveform to show progress.

self.waveform.highlightedSamples = 0..<(self.waveform.totalSamples / 2)

Zoom for detail

Render only the visible portion while progressively adding detail as you zoom.

self.waveform.zoomSamples = 0..<(self.waveform.totalSamples / 4)

Gesture control

Allow scrubbing, stretching, and scrolling with built-in gestures.

self.waveform.doesAllowScrubbing = true
self.waveform.doesAllowStretch = true
self.waveform.doesAllowScroll = true

Animated updates

Animate property changes for smoother UI feedback.

UIView.animate(withDuration: 0.3) {
    let randomNumber = arc4random() % self.waveform.totalSamples
    self.waveform.highlightedSamples = 0 ..< randomNumber
}

Rendering quality

• Antialiased waveforms draw extra pixels to avoid jagged edges.
• Autolayout-driven size changes trigger re-rendering to prevent pixelation.
• Supports iOS 15+ and visionOS 1.0+.
• Includes unit tests running on GitHub Actions.

Installation

Use Swift Package Manager: in Xcode choose File > Swift Packages > Add Package Dependency and point to this repository. Legacy installation options are available if needed.

API

Following is the complete API for this module:

• FDWaveformView (open class, subclass of UIView)

  • init() (public init) default initializer
  • delegate: FDWaveformViewDelegate? (open var, get/set) delegate for loading and rendering callbacks
  • audioURL: URL? (open var, get/set) audio file to render asynchronously
  • totalSamples: Int (open var, get) sample count of the loaded asset
  • highlightedSamples: CountableRange<Int>? (open var, get/set) range tinted with progressColor
  • zoomSamples: CountableRange<Int> (open var, get/set) range currently displayed
  • doesAllowScrubbing: Bool (open var, get/set) enable tap and pan scrubbing
  • doesAllowStretch: Bool (open var, get/set) enable pinch-to-zoom
  • doesAllowScroll: Bool (open var, get/set) enable panning across the waveform
  • wavesColor: UIColor (open var, get/set) tint for the base waveform image
  • progressColor: UIColor (open var, get/set) tint for the highlighted waveform
  • loadingInProgress: Bool (open var, get) indicates async load in progress

• FDWaveformViewDelegate (@objc public protocol)

  • waveformViewWillRender(_ waveformView: FDWaveformView) (optional)
  • waveformViewDidRender(_ waveformView: FDWaveformView) (optional)
  • waveformViewWillLoad(_ waveformView: FDWaveformView) (optional)
  • waveformViewDidLoad(_ waveformView: FDWaveformView) (optional)
  • waveformDidBeginPanning(_ waveformView: FDWaveformView) (optional)
  • waveformDidEndPanning(_ waveformView: FDWaveformView) (optional)
  • waveformDidEndScrubbing(_ waveformView: FDWaveformView) (optional)

A couple other things are exposed that we do not consider public API:

• FDWaveformView (implements UIGestureRecognizerDelegate)
  • gestureRecognizer(_:shouldRecognizeSimultaneouslyWith:) -> Bool

Testing

Find an available simulator:

xcrun simctl list devices available | grep iPhone

Build and test using a simulator ID from the output:

# Build the library
xcodebuild build -scheme FDWaveformView -destination 'id=XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX'

# Run unit tests
xcodebuild test -scheme FDWaveformView -destination 'id=XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX'

# Build the Example app (requires a newer iOS simulator)
cd Example
xcodebuild build -scheme Example -destination 'id=XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX'

Contributing

• This project's layout is based on https://github.com/fulldecent/swift6-module-template