waveform.cpp

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/**********************************************************************
 ** Copyright (C) 2000-2002 Trolltech AS.  All rights reserved.
 **
 ** This file is part of the Qtopia Environment.
 **
 ** This file may be distributed and/or modified under the terms of the
 ** GNU General Public License version 2 as published by the Free Software
 ** Foundation and appearing in the file LICENSE.GPL included in the
 ** packaging of this file.
 **
 ** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 ** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 **
 ** See http://www.trolltech.com/gpl/ for GPL licensing information.
 **
 ** Contact info@trolltech.com if any conditions of this licensing are
 ** not clear to you.
 **
 **********************************************************************/
#include "waveform.h"

/* OPIE */
#include <opie2/odebug.h>
using namespace Opie::Core;

/* QT */
#include <qpainter.h>

Waveform::Waveform( QWidget *parent, const char *name, WFlags fl )
   : QWidget( parent, name, fl )
{
   pixmap = 0;
   windowSize = 100;
   samplesPerPixel = 8000 / (5 * windowSize);
   currentValue = 0;
   numSamples = 0;
   windowPosn = 0;
   window = 0;
}


void Waveform::changeSettings( int frequency, int channels )
{
   makePixmap();
//   owarn << "change waveform " << frequency << ", " << channels << "" << oendl; 
   samplesPerPixel = frequency * channels / (5 * windowSize);
//   owarn << "Waveform::changeSettings " << samplesPerPixel << "" << oendl; 
   if ( !samplesPerPixel )
      samplesPerPixel = 1;
   currentValue = 0;
   numSamples = 0;
   windowPosn = 0;
   draw();
}


Waveform::~Waveform()
{
   if ( window )
      delete[] window;
   if ( pixmap )
      delete pixmap;
}


void Waveform::reset()
{
   makePixmap();
   currentValue = 0;
   numSamples = 0;
   windowPosn = 0;
   draw();
}


void Waveform::newSamples( const short *buf, int len )
{
   // Cache the object values in local variables.
   int samplesPerPixel = this->samplesPerPixel;
   int currentValue = this->currentValue;
   int numSamples = this->numSamples;
   short *window = this->window;
   int windowPosn = this->windowPosn;
   int windowSize = this->windowSize;

   // Average the incoming samples to scale them to the window.
   while ( len > 0 ) {
      currentValue += *buf++;
      --len;
      if ( ++numSamples >= samplesPerPixel ) {
         window[windowPosn++] = (short)(currentValue / numSamples);
         if ( windowPosn >= windowSize ) {
            this->windowPosn = windowPosn;
            draw();
            windowPosn = 0;
         }
         numSamples = 0;
         currentValue = 0;
      }
   }

   // Copy the final state back to the object.
//owarn << "" << currentValue << ", " << numSamples << ", " << windowPosn << "" << oendl; 
 this->currentValue = currentValue;
   this->numSamples = numSamples;
   this->windowPosn = windowPosn;
}


void Waveform::makePixmap()
{
   if ( !pixmap ) {
      pixmap = new QPixmap( size() );
      windowSize = pixmap->width();
      window = new short [windowSize];
   }
}


void Waveform::draw()
{
   pixmap->fill( Qt::black );
   QPainter painter;
   painter.begin( pixmap );
   painter.setPen( Qt::green );

   int middle = pixmap->height() / 2;
   int mag;
   short *window = this->window;
   int posn;
   int size = windowPosn;
   for( posn = 0; posn < size; ++posn )
   {
      mag = (window[posn] * middle / 32768);
      painter.drawLine(posn, middle - mag, posn, middle + mag);
   }
   if ( windowPosn < windowSize )
   {
      painter.drawLine(windowPosn, middle, windowSize, middle);
   }

   painter.end();

   paintEvent( 0 );
}


void Waveform::paintEvent( QPaintEvent * )
{
   QPainter painter;
   painter.begin( this );

   if ( pixmap ) {
      painter.drawPixmap( 0, 0, *pixmap );
   } else {
      painter.setPen( Qt::green );
      QSize sz = size();
      painter.drawLine(0, sz.height() / 2, sz.width(), sz.height() / 2);
   }

   painter.end();
}

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