MeterTable.h
/* |
File: MeterTable.h |
Abstract: Class for handling conversion from linear scale to dB |
Version: 1.4.3 |
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*/ |
#include <stdlib.h> |
#include <stdio.h> |
#include <math.h> |
class MeterTable |
{ |
public: |
// MeterTable constructor arguments: |
// inNumUISteps - the number of steps in the UI element that will be drawn. |
// This could be a height in pixels or number of bars in an LED style display. |
// inTableSize - The size of the table. The table needs to be large enough that there are no large gaps in the response. |
// inMinDecibels - the decibel value of the minimum displayed amplitude. |
// inRoot - this controls the curvature of the response. 2.0 is square root, 3.0 is cube root. But inRoot doesn't have to be integer valued, it could be 1.8 or 2.5, etc. |
MeterTable(float inMinDecibels = -80., size_t inTableSize = 400, float inRoot = 2.0); |
~MeterTable(); |
float ValueAt(float inDecibels) |
{ |
if (inDecibels < mMinDecibels) return 0.; |
if (inDecibels >= 0.) return 1.; |
int index = (int)(inDecibels * mScaleFactor); |
return mTable[index]; |
} |
private: |
float mMinDecibels; |
float mDecibelResolution; |
float mScaleFactor; |
float *mTable; |
}; |
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