/*************************************************************************** Graphical spline display for equalizer (c) 2004 Mark Kretschmann <markey@web.de> (c) 2005 Markus Brueffer <markus@brueffer.de> Based on code from XMMS (c) 1998-2000 Peter Alm, Mikael Alm, Olle Hallnas, Thomas Nilsson and 4Front Technologies***************************************************************************//*************************************************************************** *                                                                         * *   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.                                   * *                                                                         * ***************************************************************************/#include "amarokconfig.h"#include "equalizergraph.h"#include <qpainter.h>#include <qpixmap.h>#include <qvaluelist.h>#include <kapplication.h>EqualizerGraph::EqualizerGraph( QWidget* parent )    : QWidget( parent, 0, Qt::WNoAutoErase )    , m_backgroundPixmap( new QPixmap() )    , m_composePixmap( new QPixmap() ){}EqualizerGraph::~EqualizerGraph(){    delete m_backgroundPixmap;    delete m_composePixmap;}/////////////////////////////////////////////////////////////////////////////////////// PROTECTED/////////////////////////////////////////////////////////////////////////////////////voidEqualizerGraph::resizeEvent( QResizeEvent* ){    drawBackground();}QSizeEqualizerGraph::sizeHint() const{   return QSize( 100, 60 );}voidEqualizerGraph::paintEvent( QPaintEvent* ){    bitBlt( m_composePixmap, 0, 0, m_backgroundPixmap );    QPainter p( m_composePixmap );    // Draw middle line    int middleLineY = (int) ( ( height() - 1 ) / 2.0 + AmarokConfig::equalizerPreamp() * ( height() - 1 ) / 200.0 );    QPen pen( colorGroup().dark(), 0, Qt::DotLine);    p.setPen( pen );    p.drawLine( 8, middleLineY, width() - 1, middleLineY );    QColor color( colorGroup().highlight() );    int h, s, v;    color.getHsv( &h, &s, &v );    int i, y, ymin, ymax, py = 0;    float x[NUM_BANDS], yf[NUM_BANDS];    float gains[NUM_BANDS] = { 0, 0, 0, 0, 0, 0, 0, 0, 0};    // Don't calculate 0 and NUM_BANDS-1 for accuracy reasons    for ( i = 1; i < NUM_BANDS -1 ; i++)        x[i] = ( width() - 8 ) * i / ( NUM_BANDS -1 ) + 8;    x[ 0 ] = 8;    x[ NUM_BANDS - 1 ] = width() - 1;    if ( AmarokConfig::equalizerEnabled() )        for ( i = 0; i < NUM_BANDS; i++ )            gains[i] = ( height() - 1 ) * AmarokConfig::equalizerGains()[i] / 200.0;    init_spline( x, gains, NUM_BANDS, yf );    for ( i = 8; i < width(); i++ ) {        y = (int) ( ( height() - 1 ) / 2 - eval_spline( x, gains, yf, NUM_BANDS, i ) );        if ( y < 0 )            y = 0;        if ( y > height() - 1 )            y = height() - 1;        if ( i == 8 )            py = y;        if ( y < py ) {            ymin = y;            ymax = py;        } else {            ymin = py;            ymax = y;        }        py = y;        for ( y = ymin; y <= ymax; y++ ) {            // Absolute carthesian coordinate            s = y - ( height() - 1 ) / 2;            s = QABS(s);            // Normalise to a base of 256            // short for: s / ( ( height() / 2.0 ) * 255;            s = (int) ( s * 510.0 / height() );            color.setHsv( h, 255 - s, v );            p.setPen( color );            p.drawPoint( i, y );        }    }    p.end();    bitBlt( this, 0, 0, m_composePixmap );}/////////////////////////////////////////////////////////////////////////////////////// PRIVATE/////////////////////////////////////////////////////////////////////////////////////voidEqualizerGraph::drawBackground(){    m_backgroundPixmap->resize( size() );    m_composePixmap->resize( size() );    m_backgroundPixmap->fill( colorGroup().background().dark( 105 ) );    QPainter p( m_backgroundPixmap );    // Erase background for scale    p.fillRect( 0, 0, 7, height() -1, colorGroup().background());    // Draw scale    p.setPen( colorGroup().shadow() );    p.drawLine( 7, 0, 7, height() - 1 );    p.drawLine( 0, 0, 7, 0 );    p.drawLine( 0, height() / 2 - 1, 7, height() / 2 - 1 );    p.drawLine( 0, height() - 1, 7, height() - 1 );}voidEqualizerGraph::init_spline( float* x, float* y, int n, float* y2 ){    int i, k;    float p, qn, sig, un;    QMemArray<float> u(n * sizeof(float));    y2[ 0 ] = u[ 0 ] = 0.0;    for ( i = 1; i < n - 1; i++ ) {        sig = ( (float)x[i] - x[i-1] ) / ( (float)x[i+1] - x[i-1] );        p = sig * y2[i-1] + 2.0;        y2[i] = ( sig - 1.0 ) / p;        u[i] = ( ( (float)y[i+1] - y[i] ) / ( x[i+1] - x[i] ) ) - ( ( (float)y[i] - y[i-1] ) / ( x[i] - x[i-1] ) );        u[i] = ( 6.0 * u[i] / ( x[i+1] - x[i-1] ) - sig * u[i-1] ) / p;    }    qn = un = 0.0;    y2[n-1] = ( un - qn * u[n-2] ) / ( qn * y2[n-2] + 1.0 );    for ( k = n - 2; k >= 0; k-- )        y2[k] = y2[k] * y2[k+1] + u[k];}floatEqualizerGraph::eval_spline( float xa[], float ya[], float y2a[], int n, float x ){    int klo, khi, k;    float h, b, a;    klo = 0;    khi = n - 1;    while ( khi - klo > 1 ) {        k = ( khi + klo ) >> 1;        if ( xa[k] > x )            khi = k;        else            klo = k;    }    h = xa[khi] - xa[klo];    a = ( xa[khi] - x ) / h;    b = ( x - xa[klo] ) / h;    return ( a * ya[klo] + b * ya[khi] + ( ( a*a*a - a ) * y2a[klo] + ( b*b*b - b ) * y2a[khi] ) * ( h*h ) / 6.0 );}