/*********************************************************
Alexis C. Montenegro © January 2006                       
Use and/or modify this code freely. If you redistribute it
please include this and/or any other comment blocks and a 
description of any changes you make.                      
**********************************************************/

var fpArray = new Array();

function preMain() {
    setPriceStudy(false);
    setStudyTitle("Klinger Volume Osc");
    setCursorLabelName("KVO",0);
    setCursorLabelName("Signal",1);
    setDefaultBarFgColor(Color.blue, 0);
    setDefaultBarFgColor(Color.red, 1);
    setPlotType(PLOTTYPE_LINE,0);
    setPlotType(PLOTTYPE_LINE,1);
    setDefaultBarThickness(1,0);
    setDefaultBarThickness(1,1);
    var x=0;
    fpArray[x] = new FunctionParameter("Fast", FunctionParameter.NUMBER);
	with(fpArray[x++]){
        setLowerLimit(1);		
        setDefault(34);
    }
    fpArray[x] = new FunctionParameter("Slow", FunctionParameter.NUMBER);
	with(fpArray[x++]){
        setLowerLimit(1);		
        setDefault(55);
    }
    fpArray[x] = new FunctionParameter("Signal", FunctionParameter.NUMBER);
	with(fpArray[x++]){
        setLowerLimit(1);		
        setDefault(13);
    }
	fpArray[x] = new FunctionParameter("Symbol", FunctionParameter.STRING);
    with(fpArray[x++]){
        setDefault();
	}
	fpArray[x] = new FunctionParameter("Interval", FunctionParameter.STRING);
	with(fpArray[x++]){
        setDefault();
    }
    fpArray[x] = new FunctionParameter("Params", FunctionParameter.BOOLEAN);
	with(fpArray[x++]){
        setName("Show Parameters");
        setDefault(false);
    }
}

var bInit = false
var xKVO = null;
var xSignal = null;

function main(Fast,Slow,Signal,Symbol,Interval,Params){
    if(bInit==false){
        if(Symbol == null) Symbol = getSymbol();
        if(Interval == null) Interval = getInterval();
        var vSymbol = Symbol+","+Interval;
        xKVO = getSeries(efsInternal("calcKVO",Fast,Slow,sym(vSymbol)));
        xSignal = getSeries(ema(Signal,xKVO));
        addBand(0, PS_SOLID, 1, Color.black,"0");
        setShowTitleParameters(eval(Params));
        bInit = true;
    }
    return new Array (xKVO,xSignal);
}

var xVForce  = null;
var xFastAvg = null;
var xSlowAvg = null;

function calcKVO(fast,slow,source){
    if(xVForce==null) xVForce = efsInternal("calcVforce")
    if(xFastAvg==null) xFastAvg = ema(fast,xVForce);
    if(xSlowAvg==null) xSlowAvg = ema(slow,xVForce);
    var nFastAvg = xFastAvg.getValue(0);
    var nSlowAvg = xSlowAvg.getValue(0);
    if(nFastAvg==null||nSlowAvg==null) return;
    return (nFastAvg-nSlowAvg);
}

var xInit = false;
var xHLC = null;
var xHigh = null;
var xLow = null;
var xVol = null;
var DM = 0;
var DM_1 = 0;
var CM = 0;
var CM_1 = 0;
var Trend = 0;
var Trend_1 = 0;

function calcVforce(){
    if(xInit==false){
        xHLC = hlc3();
        xHigh = high();
        xLow = low();
        xVol = volume();
        xInit = true;
    }
    if(getBarState()==BARSTATE_NEWBAR){
        Trend_1 = Trend;
        DM_1 = DM;
        CM_1 = CM;
    }    
    DM = xHigh.getValue(0)-xLow.getValue(0);
    var nVforce = 0;
    if(xHLC.getValue(0) > xHLC.getValue(-1)){
        Trend = 1;
    }else{
        Trend = -1;
    }
    if(Trend==Trend_1){
        CM = CM_1 + DM;
    }else{
        CM = DM_1 + DM;
    }   
    if(CM != 0){
        nVforce = xVol.getValue(0)*Math.abs(2*(DM/CM)-1)*Trend*100;
    }
    return nVforce;
}