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      1 // Copyright 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "ui/app_list/speech_ui_model.h"
      6 
      7 #include <algorithm>
      8 
      9 namespace app_list {
     10 
     11 namespace {
     12 
     13 // The default sound level, just gotten from the developer device.
     14 const int16 kDefaultSoundLevel = 200;
     15 
     16 }  // namespace
     17 
     18 SpeechUIModel::SpeechUIModel(SpeechRecognitionState initial_state)
     19     : state_(initial_state),
     20       minimum_sound_level_(kDefaultSoundLevel),
     21       maximum_sound_level_(kDefaultSoundLevel) {}
     22 
     23 SpeechUIModel::~SpeechUIModel() {}
     24 
     25 void SpeechUIModel::SetSpeechResult(const base::string16& result,
     26                                     bool is_final) {
     27   if (result_ == result && is_final_ == is_final)
     28     return;
     29 
     30   result_ = result;
     31   is_final_ = is_final;
     32   FOR_EACH_OBSERVER(SpeechUIModelObserver,
     33                     observers_,
     34                     OnSpeechResult(result, is_final));
     35 }
     36 
     37 void SpeechUIModel::UpdateSoundLevel(int16 level) {
     38   if (sound_level_ == level)
     39     return;
     40 
     41   sound_level_ = level;
     42 
     43   // Tweak the sound level limits adaptively.
     44   // - min is the minimum value during the speech recognition starts but speech
     45   //   itself hasn't started.
     46   // - max is the maximum value when the user speaks.
     47   if (state_ == SPEECH_RECOGNITION_IN_SPEECH)
     48     maximum_sound_level_ = std::max(level, maximum_sound_level_);
     49   else
     50     minimum_sound_level_ = std::min(level, minimum_sound_level_);
     51 
     52   if (maximum_sound_level_ < minimum_sound_level_) {
     53     maximum_sound_level_ = std::max(
     54         static_cast<int16>(minimum_sound_level_ + kDefaultSoundLevel),
     55         kint16max);
     56   }
     57 
     58   int16 range = maximum_sound_level_ - minimum_sound_level_;
     59   uint8 visible_level = 0;
     60   if (range > 0) {
     61     int16 visible_level_in_range =
     62         std::min(std::max(minimum_sound_level_, sound_level_),
     63                  maximum_sound_level_);
     64     visible_level =
     65         (visible_level_in_range - minimum_sound_level_) * kuint8max / range;
     66   }
     67 
     68   FOR_EACH_OBSERVER(SpeechUIModelObserver,
     69                     observers_,
     70                     OnSpeechSoundLevelChanged(visible_level));
     71 }
     72 
     73 void SpeechUIModel::SetSpeechRecognitionState(
     74     SpeechRecognitionState new_state) {
     75   if (state_ == new_state)
     76     return;
     77 
     78   state_ = new_state;
     79   // Revert the min/max sound level to the default.
     80   if (state_ != SPEECH_RECOGNITION_RECOGNIZING &&
     81       state_ != SPEECH_RECOGNITION_IN_SPEECH) {
     82     minimum_sound_level_ = kDefaultSoundLevel;
     83     maximum_sound_level_ = kDefaultSoundLevel;
     84   }
     85 
     86   FOR_EACH_OBSERVER(SpeechUIModelObserver,
     87                     observers_,
     88                     OnSpeechRecognitionStateChanged(new_state));
     89 }
     90 
     91 void SpeechUIModel::AddObserver(SpeechUIModelObserver* observer) {
     92   observers_.AddObserver(observer);
     93 }
     94 
     95 void SpeechUIModel::RemoveObserver(SpeechUIModelObserver* observer) {
     96   observers_.RemoveObserver(observer);
     97 }
     98 
     99 }  // namespace app_list
    100