//+------------------------------------------------------------------+
//|                                                  Custom MACD.mq4 |
//|                   Copyright 2005-2014, MetaQuotes Software Corp. |
//|                                              http://www.mql4.com |
//+------------------------------------------------------------------+
#property copyright   "2005-2014, MetaQuotes Software Corp."
#property link        "http://www.mql4.com"
#property description "Moving Averages Convergence/Divergence"
#property strict

#include <MovingAverages.mqh>

//--- indicator settings
#property  indicator_separate_window
#property  indicator_buffers 2
#property  indicator_color1  Silver
#property  indicator_color2  Red
#property  indicator_width1  2
//--- indicator parameters
input int InpFastEMA=12;   // Fast EMA Period
input int InpSlowEMA=26;   // Slow EMA Period
input int InpSignalSMA=9;  // Signal SMA Period
input bool compare_levels = true;
//--- indicator buffers
double    ExtMacdBuffer[];
double    ExtSignalBuffer[];
//--- right input parameters flag
bool      ExtParameters=false;

double min, max;
datetime Update_Time;
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit(void)
  {
     
   IndicatorDigits(Digits+1);
//--- drawing settings
   SetIndexStyle(0,DRAW_HISTOGRAM);
   SetIndexStyle(1,DRAW_LINE);
   SetIndexDrawBegin(1,InpSignalSMA);
//--- indicator buffers mapping

   if(compare_levels) IndicatorSetDouble(INDICATOR_LEVELVALUE,0);

   SetIndexBuffer(0,ExtMacdBuffer);
   SetIndexBuffer(1,ExtSignalBuffer);
//--- name for DataWindow and indicator subwindow label
   IndicatorShortName("MACD("+IntegerToString(InpFastEMA)+","+IntegerToString(InpSlowEMA)+","+IntegerToString(InpSignalSMA)+")");
   SetIndexLabel(0,"MACD");
   SetIndexLabel(1,"Signal");
//--- check for input parameters
   if(InpFastEMA<=1 || InpSlowEMA<=1 || InpSignalSMA<=1 || InpFastEMA>=InpSlowEMA)
     {
      Print("Wrong input parameters");
      ExtParameters=false;
      return(INIT_FAILED);
     }
   else
      ExtParameters=true;
//--- initialization done
   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//| Moving Averages Convergence/Divergence                           |
//+------------------------------------------------------------------+
int OnCalculate (const int rates_total,
                 const int prev_calculated,
                 const datetime& time[],
                 const double& open[],
                 const double& high[],
                 const double& low[],
                 const double& close[],
                 const long& tick_volume[],
                 const long& volume[],
                 const int& spread[])
  {
   int i,limit;
//---

   if(rates_total<=InpSignalSMA || !ExtParameters)
      return(0);
//--- last counted bar will be recounted
   limit=rates_total-prev_calculated;
   if(prev_calculated>0)
      limit++;
      
//--- macd counted in the 1-st buffer
   for(i=0; i<limit; i++) {
      ExtMacdBuffer[i]=iMA(NULL,0,InpFastEMA,0,MODE_EMA,PRICE_CLOSE,i)-
                    iMA(NULL,0,InpSlowEMA,0,MODE_EMA,PRICE_CLOSE,i);
      
   } 

              
//--- signal line counted in the 2-nd buffer
   SimpleMAOnBuffer(rates_total,prev_calculated,0,InpSignalSMA,ExtMacdBuffer,ExtSignalBuffer);
//--- done
   return(rates_total);
  }
//+------------------------------------------------------------------+

//+-----------------------------------------------------------------------------------------------+ 
void OnChartEvent(const int id,const long &lparam,const double &dparam,const string &sparam)
  {
   if(compare_levels) {
      if(id==CHARTEVENT_CHART_CHANGE) {
         min = 0; max = 0;
         double new_levels = 0;
         for(int i=WindowLastVisibleBar(); i<=WindowFirstVisibleBar(); i++) {
            if(ExtMacdBuffer[i] < min) min = ExtMacdBuffer[i];
            if(ExtMacdBuffer[i] > max) max = ExtMacdBuffer[i]; 
         }
         
         if(MathAbs(min) > max) new_levels = MathAbs(min);
         else new_levels = max;
         
         int pnt = 2;
         if(new_levels > 0.05) pnt = 10;
         else if(new_levels > 0.1) pnt = 20;
         IndicatorSetDouble(INDICATOR_MINIMUM,-new_levels-pnt*Point); 
         IndicatorSetDouble(INDICATOR_MAXIMUM,new_levels+pnt*Point); 
           
         //Print(WindowFirstVisibleBar()+ "/"+ min + "/"+ max); 
      }  
   }            
}

//+-------------
int WindowLastVisibleBar(){
   int tmpnum = WindowFirstVisibleBar() - WindowBarsPerChart();
   int ret=tmpnum;
   if(tmpnum < 0){ ret=0; }
   return(ret);
}