/* basic variable defs 
 ud: up-Day (Close up from Open)
 dd: down-Day (Close down from Open)
 uc: up-Close (Close up from previous Close)
 dc: down-Close: (Close down from previous Close)
*/
C1 = Ref(C, -1);
uc = C > C1; dc = C <= C1;
ud = C > O; dd = C <= O;

/*
Volume Day types: 
 green: up-day and up-close
 yellow: up-day but down-close
 red: down-day and down-close
 blue: down-day but up-close
 white: close equals open, close equals previous close

(currently unused vtypes are for future enhancements)
*/
green = 1; blue = 2; yellow = 3; red = 4; white = 5;
VType = IIf(ud, 			
			IIf(uc, green, yellow),
		 IIf(dd, 
			IIf(dc, red, blue), white));

/* green volume: up-day and up-close*/
gv = IIf(VType == green, V, 0); 
/* yellow volume: up-day but down-close */
yv = IIf(VType == yellow, V, 0); 
/* red volume: down-day and down-close */
rv = IIf(VType == red, V, 0); 
/* blue volume: down-day but up-close */
bv = IIf(VType == blue, V, 0); 

/* split up volume of up-close days from down-close days - (for the purposes of
this volume display indicator, up-days that closed down from the previous close
are considered bearish volume days, and conversely, down-days that nevertheless
closed up from the previous close are considered bullish volume days - my
testing indicates this is more accurate than using ordinary up-days and
down-days) */
uv = gv + bv; uv1 = Ref(uv, -1); /* up volume */
dv = rv + yv; dv1 = Ref(dv, -1); /* down volume */

/* create moving average period parameters */
VolPer = Param("Adjust Vol. MA per.", 34, 1, 255, 1);
ConvPer = Param("Adjust Conv. MA per.", 9, 1, 255, 1);

/* create triple exponential moving avearges of separate up and down volume
moving averages */
MAuv = TEMA(uv, VolPer ); mauv1 = Ref(mauv, -1);
MAdv = TEMA(dv, VolPer ); madv1 = Ref(madv, -1);
MAtv = TEMA(V, VolPer );//total volume

/* Switch for Horizontal lines indicating current level of positive and
negative volume for ease in comparing to past highs/lows - toggle via
parmameter window */
OscillatorOnly = Param("Show Oscillator Only", 0, 0, 1, 1);
CompareBullVolume = Param("Show Bull Level", 1, 0, 1, 1);
if(CompareBullvolume AND !OscillatorOnly){
Plot(SelectedValue(MAuv), "", colorGreen, styleLine);
}

CompareBearVolume = Param("Show Bear Level", 1, 0, 1, 1);
if(CompareBearVolume AND !OscillatorOnly){
Plot(SelectedValue(MAdv), "", colorRed, styleLine);
}

/* Volume Segment Switches - toggle via parameter window */
bullvolume = Param("Show Bull Volume", 1, 0, 1, 1);
bearvolume = Param("Show Bear Volume", 1, 0, 1, 1);
totalvolume = Param("Show Total Volume", 1, 0, 1, 1);

/* plot volume lines and histograms if toggled on: */
bearToFront = Param("Show Bear Vol in Front", 0, 0, 1, 1);
if(bearToFront AND !OscillatorOnly){
Plot(MAdv, "", colorRed, styleHistogram|styleNoLabel);
}
if(bullvolume AND !OscillatorOnly){
Plot(MAuv, "Average Bull Volume", colorGreen, styleHistogram|styleNoLabel);
}
if(bearvolume AND !OscillatorOnly){
Plot(MAdv, "Average Bear Volume", colorRed, styleHistogram|styleNoLabel);
}
if(totalVolume AND !OscillatorOnly){
Plot(MAtv, "Total Volume", colorWhite, styleHistogram|styleNoLabel);
Plot(MAtv, "", colorWhite, styleLine);
}
if(bullvolume AND !OscillatorOnly){
Plot(MAuv, "", colorGreen, styleLine);
}
if(bearvolume AND !OscillatorOnly){
Plot(MAdv, "", colorRed, styleLine);
}

/* better visibility of zero line: */
Plot(0, "", colorBlue, 1);

/* Rise/Fall Convergence variables:  */
Converge = (TEMA(MAuv - MAdv, ConvPer));
Converge1 = Ref(Converge, -1);
ConvergeUp = Converge > Converge1;
ConvergeOver = Converge > 0;
rising = ConvergeUp AND ConvergeOver;
falling = !ConvergeUp AND ConvergeOver;

/* Rise/Fall Convergence Oscillator Switch  - toggle via parameter window -
(provides a better view of resulting combination of battling bull/bear volume
forces) */
convergenceOscillator = Param("Show Oscillator", 0, 0, 1, 1);
if(convergenceOscillator OR OscillatorOnly){
Plot(Converge, "Bull/Bear Volume Convergence/Divergence", colorViolet,
1|styleLeftAxisScale|styleNoLabel|styleThick);
Plot(0,"", colorYellow, 1|styleLeftAxisScale|styleNoLabel);
}

/********************************************************
 Convergence Rise/Fall Shadows: 

 (provides a more easily visible display of rising and falling  bull/bear
volume convergence) - toggle via parameter window 

-posiitive Volume exceeding negative Volume: Light shadow
-negative volume exceeding positive volume: dark shadow
-if you use standard gray background - best shadows are:
-my greys: 14 = (216, 216, 216); 15 = (168, 168, 168));
-best substitute? using AB color constants?
-light: colorpalegreen; dark: colorRose;? 
-(depends on your color scheme - customize to your tastes)
**********************************************************/

/* uncomment if you use my custom color greys: */
riseFallColor = IIf(rising, 14,15); //my custom shadow greys

/* comment out if you use my custom color gray shadows: */
/* riseFallColor = IIf(rising, colorPaleGreen,colorRose); */

/* Rise/Fall Convergence Plot Switch - toggle via parameter window */
riseFallShadows = Param("Show RiseFallShadows", 0, 0, 1, 1);
if(riseFallShadows){
Plot(IIf(rising OR falling, 1, 0), "", riseFallColor,
styleHistogram|styleArea|styleOwnScale|styleNoLabel);
}
GraphXSpace = 0.5;