1 /* 2 * Copyright (C) 2010 Google Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of 14 * its contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY 18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY 21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #ifndef AudioParam_h 30 #define AudioParam_h 31 32 #include "PlatformString.h" 33 #include <sys/types.h> 34 #include <wtf/PassRefPtr.h> 35 #include <wtf/RefCounted.h> 36 37 namespace WebCore { 38 39 class AudioParam : public RefCounted<AudioParam> { 40 public: 41 static const double DefaultSmoothingConstant; 42 static const double SnapThreshold; 43 44 static PassRefPtr<AudioParam> create(const String& name, double defaultValue, double minValue, double maxValue, unsigned units = 0) 45 { 46 return adoptRef(new AudioParam(name, defaultValue, minValue, maxValue, units)); 47 } 48 49 AudioParam(const String& name, double defaultValue, double minValue, double maxValue, unsigned units = 0) 50 : m_name(name) 51 , m_value(defaultValue) 52 , m_defaultValue(defaultValue) 53 , m_minValue(minValue) 54 , m_maxValue(maxValue) 55 , m_units(units) 56 , m_smoothedValue(defaultValue) 57 , m_smoothingConstant(DefaultSmoothingConstant) 58 { 59 } 60 61 float value() const { return static_cast<float>(m_value); } 62 63 void setValue(float); 64 65 String name() const { return m_name; } 66 67 float minValue() const { return static_cast<float>(m_minValue); } 68 float maxValue() const { return static_cast<float>(m_maxValue); } 69 float defaultValue() const { return static_cast<float>(m_defaultValue); } 70 unsigned units() const { return m_units; } 71 72 // Value smoothing: 73 74 // When a new value is set with setValue(), in our internal use of the parameter we don't immediately jump to it. 75 // Instead we smoothly approach this value to avoid glitching. 76 float smoothedValue() const { return static_cast<float>(m_smoothedValue); } 77 78 // Smoothly exponentially approaches to (de-zippers) the desired value. 79 // Returns true if smoothed value has already snapped exactly to value. 80 bool smooth(); 81 82 void resetSmoothedValue() { m_smoothedValue = m_value; } 83 void setSmoothingConstant(double k) { m_smoothingConstant = k; } 84 85 private: 86 String m_name; 87 double m_value; 88 double m_defaultValue; 89 double m_minValue; 90 double m_maxValue; 91 unsigned m_units; 92 93 // Smoothing (de-zippering) 94 double m_smoothedValue; 95 double m_smoothingConstant; 96 }; 97 98 } // namespace WebCore 99 100 #endif // AudioParam_h 101
