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fft_result.cc

/*
    Copyright (C) 2006 Paul Davis
      Written by Sampo Savolainen

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include <fft_result.h>
#include <fft_graph.h>
#include <cstdlib>
#include <string>
#include <cmath>

#include <iostream>

using namespace std;

FFTResult::FFTResult(FFTGraph *graph, Gdk::Color color, string trackname)
{
      _graph = graph;
      
      _windowSize = _graph->windowSize();
      _dataSize   = _windowSize / 2;

      _averages = 0;

      _data = (float *) malloc(sizeof(float) * _dataSize);
      memset(_data,0,sizeof(float) * _dataSize);

      _color     = color;
      _trackname = trackname;
}

void
FFTResult::analyzeWindow(float *window)
{
      _graph->analyze(window, _data);
      _averages++;
}

void
FFTResult::finalize()
{
      if (_averages == 0) {
            _minimum = 0.0;
            _maximum = 0.0;
            return;
      }
      
      // Average & scale
      for (int i = 0; i < _dataSize; i++) {
            _data[i] /= _averages;
            _data[i]  = 10.0f * log10f(_data[i]); 
      }

      // find min & max
      _minimum = _maximum = _data[0];
      
      for (int i = 1; i < _dataSize; i++) {
            if (_data[i] < _minimum        && !isinf(_data[i])) {
                  _minimum = _data[i];
            } else if (_data[i] > _maximum && !isinf(_data[i])) {
                  _maximum = _data[i];
            }
      }

      _averages = 0;
}

FFTResult::~FFTResult()
{
      free(_data);
}


float
FFTResult::sampleAt(int x)
{
      if (x < 0 || x>= _dataSize)
            return 0.0f;

      return _data[x];
}


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