Add Swift API for MatchaTTS models. (#1684)

swift-api-examples/tts-matcha-en.swift

@@ -0,0 +1,65 @@
+class MyClass {
+  func playSamples(samples: [Float]) {
+    print("Play \(samples.count) samples")
+  }
+}
+
+func run() {
+  let acousticModel = "./matcha-icefall-en_US-ljspeech/model-steps-3.onnx"
+  let vocoder = "./hifigan_v2.onnx"
+  let tokens = "./matcha-icefall-en_US-ljspeech/tokens.txt"
+  let dataDir = "./matcha-icefall-en_US-ljspeech/espeak-ng-data"
+  let matcha = sherpaOnnxOfflineTtsMatchaModelConfig(
+    acousticModel: acousticModel,
+    vocoder: vocoder,
+    tokens: tokens,
+    dataDir: dataDir
+  )
+  let modelConfig = sherpaOnnxOfflineTtsModelConfig(matcha: matcha, debug: 0)
+  var ttsConfig = sherpaOnnxOfflineTtsConfig(model: modelConfig)
+
+  let myClass = MyClass()
+
+  // We use Unretained here so myClass must be kept alive as the callback is invoked
+  //
+  // See also
+  // https://medium.com/codex/swift-c-callback-interoperability-6d57da6c8ee6
+  let arg = Unmanaged<MyClass>.passUnretained(myClass).toOpaque()
+
+  let callback: TtsCallbackWithArg = { samples, n, arg in
+    let o = Unmanaged<MyClass>.fromOpaque(arg!).takeUnretainedValue()
+    var savedSamples: [Float] = []
+    for index in 0..<n {
+      savedSamples.append(samples![Int(index)])
+    }
+
+    o.playSamples(samples: savedSamples)
+
+    // return 1 so that it continues generating
+    return 1
+  }
+
+  let tts = SherpaOnnxOfflineTtsWrapper(config: &ttsConfig)
+
+  let text =
+    "Friends fell out often because life was changing so fast. The easiest thing in the world was to lose touch with someone."
+  let sid = 0
+  let speed: Float = 1.0
+
+  let audio = tts.generateWithCallbackWithArg(
+    text: text, callback: callback, arg: arg, sid: sid, speed: speed)
+  let filename = "test-matcha-en.wav"
+  let ok = audio.save(filename: filename)
+  if ok == 1 {
+    print("\nSaved to:\(filename)")
+  } else {
+    print("Failed to save to \(filename)")
+  }
+}
+
+@main
+struct App {
+  static func main() {
+    run()
+  }
+}