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#include "levelmeter.h"
#include <tqpainter.h>
#include <math.h>
LevelMeter::LevelMeter( TQWidget *parent )
: TQWidget(parent), m_level(0.0f)
{
setBackgroundMode( NoBackground );
}
// Map linear 0..1 amplitude to dB display position 0..1 over a 60dB range.
// -60dB = bottom, 0dB = top. Matches how real VU meters look.
static float toDisplayLevel( float linear )
{
if ( linear < 0.001f ) return 0.0f;
float db = 20.0f * log10f( linear ); // e.g. 0.3 → -10.5 dB
float pos = ( db + 60.0f ) / 60.0f; // -60..0 dB → 0..1
if ( pos < 0.0f ) pos = 0.0f;
if ( pos > 1.0f ) pos = 1.0f;
return pos;
}
void LevelMeter::setLevel( float level )
{
if ( level < 0.0f ) level = 0.0f;
if ( level > 1.0f ) level = 1.0f;
float display = toDisplayLevel( level );
if ( display > m_level )
m_level = m_level * 0.3f + display * 0.7f; // fast attack, not instant
else {
m_level *= 0.94f; // slow decay ~1.5s to floor
if ( m_level < 0.001f ) m_level = 0.0f;
}
update();
}
TQSize LevelMeter::sizeHint() const
{
return TQSize( 8, 48 );
}
void LevelMeter::paintEvent( TQPaintEvent * )
{
TQPainter p( this );
int w = width();
int h = height();
p.fillRect( 0, 0, w, h, TQColor( 40, 40, 40 ) );
if ( m_level <= 0.0f ) return;
struct Zone { float lo, hi; TQColor col; };
static const Zone zones[3] = {
{ 0.00f, 0.70f, TQColor( 50, 200, 50 ) },
{ 0.70f, 0.90f, TQColor( 230, 200, 0 ) },
{ 0.90f, 1.00f, TQColor( 220, 40, 40 ) },
};
for ( int z = 0; z < 3; z++ ) {
if ( m_level <= zones[z].lo ) break;
float segEnd = ( m_level < zones[z].hi ) ? m_level : zones[z].hi;
int yTop = h - (int)( segEnd * h );
int yBot = h - (int)( zones[z].lo * h );
p.fillRect( 0, yTop, w, yBot - yTop, zones[z].col );
}
}
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