_SECTION_BEGIN("HEIKIN ASHI CANDLESTICK OSCILLATOR");
function ZeroLagTEMA( array, period ) 
{ 
 TMA1 = TEMA( array, period ); 
 TMA2 = TEMA( TMA1, period ); 
 Diff = TMA1 - TMA2; 
 return TMA1 + Diff ; 
} 
 
///////////////////// 
// Heikin-Ashi code 
HaClose = (O+H+L+C)/4; 
HaOpen = AMA( Ref( HaClose, -1 ), 0.5 ); 
 
avp = Param("Up TEMA avg", 34, 1, 100 ); 
avpdn = Param("Dn TEMA avg", 34, 1, 100 ); 
 
// Velvoort is using not original, but modified Heikin-Ashi close 
HaClose = ( HaClose + HaOpen + Max( H, HaOpen ) + Min( L, HaOpen ) )/4; 
 
// up average 
ZlHa = ZeroLagTEMA( HaClose, avp ); 
ZlCl = ZeroLagTEMA( ( H + L ) / 2, avp ); 
ZlDif = ZlCl - ZlHa; 
 
keep1 = Hold( HaClose >= HaOpen, 2 ); 
keep2 = ZlDif >= 0; 
keeping = keep1 OR keep2; 
keepall = keeping OR ( Ref( keeping, -1 ) AND ( C > O ) OR C >= Ref( C, -1 ) ); 
keep3 = abs( C - O ) < ( H - L ) * 0.35 AND H >= Ref( L, -1 ); 
utr = keepall OR ( Ref( keepall, -1 ) AND keep3 ); 
 
// dn average 
ZlHa = ZeroLagTEMA( HaClose, avpdn ); 
ZlCl = ZeroLagTEMA( ( H + L ) / 2, avpdn ); 
ZlDif = ZlCl - ZlHa; 
 
keep1 = Hold( HaClose < HaOpen, 2 ); 
keep2 = ZlDif < 0; 
keeping = keep1 OR keep2; 
keepall = keeping OR ( Ref( keeping, -1 ) AND ( C < O ) OR C < Ref( C, -1 ) ); 
keep3 = abs( C - O ) < ( H - L ) * 0.35 AND L <= Ref( H, -1 ); 
dtr = keepall OR ( Ref( keepall, -1 ) AND keep3 ); 
 
upw = dtr == 0 AND Ref( dtr, -1 ) AND utr; 
dnw = utr == 0 AND Ref( utr, -1 ) AND dtr; 
 
Haco = Flip( upw, dnw ); 
 
 
if( ParamToggle("Chart Type", "Price with color back|HACO wave" ) ) 
{ 
 Plot( Haco, "Haco", colorRed ); 
} 
else
{ 
 Plot( C, "Close", colorBlack, 
       ParamStyle( "Style", styleCandle, maskPrice ) ); 
 Plot( 1, "", IIf( Haco , colorPaleGreen, colorRose ), 
       styleArea | styleOwnScale, 0, 1 ); 
}
_SECTION_END();