//+------------------------------------------------------------------+
//|                                                    Demo_iATR.mq5 |
//|                        Copyright 2011, MetaQuotes Software Corp. |
//|                                              https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2000-2024, MetaQuotes Ltd."
#property link "https://www.mql5.com"
#property version "1.00"
#property description "The indicator demonstrates how to obtain data"
#property description "of indicator buffers for the iATR technical indicator."
#property description "A symbol and timeframe used for calculation of the indicator,"
#property description "are set by the symbol and period parameters."
#property description "The method of creation of the handle is set through the 'type' parameter (function type)."

#property indicator_separate_window
#property indicator_buffers 1
#property indicator_plots 1
//--- plot iATR
#property indicator_label1 "iATR"
#property indicator_type1 DRAW_LINE
#property indicator_color1 clrLightSeaGreen
#property indicator_style1 STYLE_SOLID
#property indicator_width1 1
//+------------------------------------------------------------------+
//| Enumeration of the methods of handle creation                    |
//+------------------------------------------------------------------+
enum Creation
  {
   Call_iATR,             // use iATR
   Call_IndicatorCreate   // use IndicatorCreate
  };
//--- input parameters
input int             atr_period = 14;               // period of calculation
input Creation        type       = Call_iATR;        // type of the function
input string          symbol     = "";              // symbol
input ENUM_TIMEFRAMES period     = PERIOD_CURRENT;   // timeframe
//--- indicator buffer
double iATRBuffer[];
//--- variable for storing the handle of the iAC indicator
int handle;
//--- variable for storing
string name = symbol;
//--- name of the indicator on a chart
string short_name;
//--- we will keep the number of values in the Average True Range indicator
int bars_calculated = 0;
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
  {
//--- assignment of array to indicator buffer
   SetIndexBuffer(0, iATRBuffer, INDICATOR_DATA);
//--- determine the symbol the indicator is drawn for
   name = symbol;
//--- delete spaces to the right and to the left
   StringTrimRight(name);
   StringTrimLeft(name);
//--- if it results in zero length of the 'name' string
   if(StringLen(name) == 0)
     {
      //--- take the symbol of the chart the indicator is attached to
      name = _Symbol;
     }
//--- create handle of the indicator
   if(type == Call_iATR)
      handle = iATR(name, period, atr_period);
   else
     {
      //--- fill the structure with parameters of the indicator
      MqlParam pars[1];
      pars[0].type          = TYPE_INT;
      pars[0].integer_value = atr_period;
      handle                = IndicatorCreate(name, period, IND_ATR, 1, pars);
     }
//--- if the handle is not created
   if(handle == INVALID_HANDLE)
     {
      //--- tell about the failure and output the error code
      PrintFormat("Failed to create handle of the iATR indicator for the symbol %s/%s, error code %d",
                  name,
                  EnumToString(period),
                  GetLastError());
      //--- the indicator is stopped early
      return (INIT_FAILED);
     }
//--- show the symbol/timeframe the Average True Range indicator is calculated for
   short_name = StringFormat("iATR(%s/%s, period=%d)", name, EnumToString(period), atr_period);
   IndicatorSetString(INDICATOR_SHORTNAME, short_name);
//--- normal initialization of the indicator
   return (INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
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[])
  {
//--- number of values copied from the iATR indicator
   int values_to_copy;
//--- determine the number of values calculated in the indicator
   int calculated = BarsCalculated(handle);
   if(calculated <= 0)
     {
      PrintFormat("BarsCalculated() returned %d, error code %d", calculated, GetLastError());
      return (0);
     }
//--- if it is the first start of calculation of the indicator or if the number of values in the iATR indicator changed
//---or if it is necessary to calculated the indicator for two or more bars (it means something has changed in the price history)
   if(prev_calculated == 0 || calculated != bars_calculated || rates_total > prev_calculated + 1)
     {
      //--- if the iATRBuffer array is greater than the number of values in the iATR indicator for symbol/period, then we don't copy everything
      //--- otherwise, we copy less than the size of indicator buffers
      if(calculated > rates_total)
         values_to_copy = rates_total;
      else
         values_to_copy = calculated;
     }
   else
     {
      //--- it means that it's not the first time of the indicator calculation, and since the last call of OnCalculate()
      //--- for calculation not more than one bar is added
      values_to_copy = (rates_total - prev_calculated) + 1;
     }
//--- fill the iATRBuffer array with values of the Average True Range indicator
//--- if FillArrayFromBuffer returns false, it means the information is nor ready yet, quit operation
   if(!FillArrayFromBuffer(iATRBuffer, handle, values_to_copy))
      return (0);
//--- form the message
   string comm = StringFormat("%s ==>  Updated value in the indicator %s: %d",
                              TimeToString(TimeCurrent(), TIME_DATE | TIME_SECONDS),
                              short_name,
                              values_to_copy);
//--- display the service message on the chart
   Comment(comm);
//--- memorize the number of values in the Average True Range indicator
   bars_calculated = calculated;
//--- return the prev_calculated value for the next call
   return (rates_total);
  }
//+------------------------------------------------------------------+
//| Filling indicator buffers from the iATR indicator                |
//+------------------------------------------------------------------+
bool FillArrayFromBuffer(double &values[],     // indicator buffer for ATR values
                         int     ind_handle,   // handle of the iATR indicator
                         int     amount        // number of copied values
                        )
  {
//--- reset error code
   ResetLastError();
//--- fill a part of the iATRBuffer array with values from the indicator buffer that has 0 index
   if(CopyBuffer(ind_handle, 0, 0, amount, values) < 0)
     {
      //--- if the copying fails, tell the error code
      PrintFormat("Failed to copy data from the iATR indicator, error code %d", GetLastError());
      //--- quit with zero result - it means that the indicator is considered as not calculated
      return (false);
     }
//--- everything is fine
   return (true);
  }
//+------------------------------------------------------------------+
//| Indicator deinitialization function                              |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
   if(handle != INVALID_HANDLE)
      IndicatorRelease(handle);
//--- clear the chart after deleting the indicator
   Comment("");
  }
//+------------------------------------------------------------------+