ma_Step_EMA_LK

//+------------------------------------------------------------------+
//|                                                  Step_EMA_LK.mq4 |
//|                                 Copyright © 2009, Leif Karlsson. |
//|                                        Leffemannen1973@telia.com |
//+------------------------------------------------------------------+
//| Please feel free to copy, modify and / or redistribute this      |
//| software / source code in any way you see fit.                   |
//+------------------------------------------------------------------+
//+ ********************* Shameless Ad. **************************** +
//+ * I do custom programing jobs in Java, C, X86 Assembler & MQL4 * +
//+ ***** Pleace do not hesitate to get in contact if you nead ***** +
//+ ***** something special: EA, indicator or somthing else. ******* +
//+ ****************** Leffemannen1973@telia.com ******************* +
//+ **************************************************************** +
//+------------------------------------------------------------------+
#property copyright "Copyright © 2009, Leif Kalrsson"
#property link      "mailto://Leffemannen1973@telia.com"
//+------------------------------------------------------------------+
#property  indicator_chart_window
#property  indicator_buffers 2
#property  indicator_color1  Yellow
#property  indicator_color2  Red
#property  indicator_width1  1
//+------------------------------------------------------------------+
extern int EMAPeriod = 30;
extern int ERangePeriod = 14;
extern int ERangeWindow = 8;		// Must be less then ERangePeriod, think of it as custom TF
extern string AppliedPriceText1 = "Close: 0, Open: 1, High: 2, Low: 3";
extern string AppliedPriceText2 = "Median: 4, Typical: 5, Weighted: 6";
extern int AppliedPrice = 4;
extern int PriceShift = 0;
extern int MaxBars = 4000;
//+------------------------------------------------------------------+
double UpBuffer[];
double DwBuffer[];
double Price[];
double ERange[];
double EmaAlpha = 0.0;
double ERangeAlpha = 0.0;
//+------------------------------------------------------------------+
int init() {

   	IndicatorDigits(Digits+1);
   	
   	IndicatorBuffers(4);
   	
   	SetIndexStyle(0, DRAW_LINE);
   	SetIndexStyle(1, DRAW_LINE);
   	SetIndexBuffer(0, UpBuffer);
   	SetIndexBuffer(1, DwBuffer);
   	SetIndexBuffer(2, Price);
   	SetIndexBuffer(3, ERange);
   	   	   	
   	IndicatorShortName("Step_EMA, EMAPeriod: " + EMAPeriod + ", ERangePeriod: " + ERangePeriod + " ");
   	
   	EmaAlpha = 2.0/(EMAPeriod + 1.0);
   	ERangeAlpha = 2.0/(ERangePeriod + 1.0);
   	
   	return(0);
}
//+------------------------------------------------------------------+
int start() {
	int j = 0;
	int i = IndicatorCounted();
	if(i < 0) return(-1);
	i = Bars - i;
	if(i > MaxBars) {
		i = MaxBars;
		ArrayInitialize(UpBuffer, EMPTY_VALUE);
		ArrayInitialize(DwBuffer, EMPTY_VALUE);
		ArrayInitialize(ERange, High[i]-Low[i]);
	}
	
	j = i;
	while(j >= 0) {
		Price[j] = iMA(NULL, 0, 1, 0, 0, AppliedPrice, j+PriceShift);
		j--;
	}
		
	while(i >= 0) {
		double Range = 0.0;
		double StepSize = 0.0;
		double SEma = 0.0;
		double OldSEma = 0.0;
		
		Range = High[ArrayMaximum(High, ERangeWindow, i+PriceShift+1)] - Low[ArrayMinimum(Low, ERangeWindow, i+PriceShift+1)];
		ERange[i] = (1.0-ERangeAlpha)*ERange[i+1] + ERangeAlpha*Range;
		StepSize = ERange[i];
		
		if(UpBuffer[i+1] != EMPTY_VALUE) SEma = (1.0-EmaAlpha)*UpBuffer[i+1] + EmaAlpha*Price[i];
		if(DwBuffer[i+1] != EMPTY_VALUE) SEma = (1.0-EmaAlpha)*DwBuffer[i+1] + EmaAlpha*Price[i];
		if(SEma == 0.0) SEma = Price[i];
		
		if(SEma < Price[i]-StepSize) SEma = Price[i]-StepSize;
		if(SEma > Price[i]+StepSize) SEma = Price[i]+StepSize;
		
		if(UpBuffer[i+1] == EMPTY_VALUE) OldSEma = DwBuffer[i+1];
		else OldSEma = UpBuffer[i+1];
		
		if(SEma > OldSEma) {
			UpBuffer[i] = SEma;
			DwBuffer[i] = EMPTY_VALUE;
			if(UpBuffer[i+1] == EMPTY_VALUE) UpBuffer[i+1] = OldSEma;
		}
		else {
			DwBuffer[i] = SEma;
			UpBuffer[i] = EMPTY_VALUE;
			if(DwBuffer[i+1] == EMPTY_VALUE) DwBuffer[i+1] = OldSEma;
		}
		i--;
	}	

   	return(0);
}