root/ui/app_list/speech_ui_model.cc

DEFINITIONS

1. maximum_sound_level_
2. SetSpeechResult
3. UpdateSoundLevel
4. SetSpeechRecognitionState
5. AddObserver
6. RemoveObserver

// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/app_list/speech_ui_model.h"

#include <algorithm>

namespace app_list {

namespace {

// The default sound level, just gotten from the developer device.
const int16 kDefaultSoundLevel = 200;

}  // namespace

SpeechUIModel::SpeechUIModel(SpeechRecognitionState initial_state)
    : state_(initial_state),
      minimum_sound_level_(kDefaultSoundLevel),
      maximum_sound_level_(kDefaultSoundLevel) {}

SpeechUIModel::~SpeechUIModel() {}

void SpeechUIModel::SetSpeechResult(const base::string16& result,
                                    bool is_final) {
  if (result_ == result && is_final_ == is_final)
    return;

  result_ = result;
  is_final_ = is_final;
  FOR_EACH_OBSERVER(SpeechUIModelObserver,
                    observers_,
                    OnSpeechResult(result, is_final));
}

void SpeechUIModel::UpdateSoundLevel(int16 level) {
  if (sound_level_ == level)
    return;

  sound_level_ = level;

  // Tweak the sound level limits adaptively.
  // - min is the minimum value during the speech recognition starts but speech
  //   itself hasn't started.
  // - max is the maximum value when the user speaks.
  if (state_ == SPEECH_RECOGNITION_IN_SPEECH)
    maximum_sound_level_ = std::max(level, maximum_sound_level_);
  else
    minimum_sound_level_ = std::min(level, minimum_sound_level_);

  if (maximum_sound_level_ < minimum_sound_level_) {
    maximum_sound_level_ = std::max(
        static_cast<int16>(minimum_sound_level_ + kDefaultSoundLevel),
        kint16max);
  }

  int16 range = maximum_sound_level_ - minimum_sound_level_;
  uint8 visible_level = 0;
  if (range > 0) {
    int16 visible_level_in_range =
        std::min(std::max(minimum_sound_level_, sound_level_),
                 maximum_sound_level_);
    visible_level =
        (visible_level_in_range - minimum_sound_level_) * kuint8max / range;
  }

  FOR_EACH_OBSERVER(SpeechUIModelObserver,
                    observers_,
                    OnSpeechSoundLevelChanged(visible_level));
}

void SpeechUIModel::SetSpeechRecognitionState(
    SpeechRecognitionState new_state) {
  if (state_ == new_state)
    return;

  state_ = new_state;
  // Revert the min/max sound level to the default.
  if (state_ != SPEECH_RECOGNITION_RECOGNIZING &&
      state_ != SPEECH_RECOGNITION_IN_SPEECH) {
    minimum_sound_level_ = kDefaultSoundLevel;
    maximum_sound_level_ = kDefaultSoundLevel;
  }

  FOR_EACH_OBSERVER(SpeechUIModelObserver,
                    observers_,
                    OnSpeechRecognitionStateChanged(new_state));
}

void SpeechUIModel::AddObserver(SpeechUIModelObserver* observer) {
  observers_.AddObserver(observer);
}

void SpeechUIModel::RemoveObserver(SpeechUIModelObserver* observer) {
  observers_.RemoveObserver(observer);
}

}  // namespace app_list