MQL4 Reference Constants, Enumerations and Structures Indicator Constants Custom Indicator Properties

Custom Indicators Properties

A custom indicator has a lot of settings to provide convenient displaying. These settings are made through the assignment of corresponding indicator properties using functions IndicatorSetDouble(), IndicatorSetInteger() and IndicatorSetString(). Identifiers of indicator properties are listed in the ENUM_CUSTOMIND_PROPERTY enumeration.

ENUM_CUSTOMIND_PROPERTY_INTEGER

ID	Description	Property type
INDICATOR_DIGITS	Accuracy of drawing of indicator values	int
INDICATOR_HEIGHT	Fixed height of the indicator's window (the preprocessor command #property indicator_height)	int
INDICATOR_LEVELS	Number of levels in the indicator window	int
INDICATOR_LEVELCOLOR	Color of the level line	color sets color for all levels
INDICATOR_LEVELSTYLE	Style of the level line	ENUM_LINE_STYLE sets style for all levels
INDICATOR_LEVELWIDTH	Thickness of the level line	int sets width for all levels

ENUM_CUSTOMIND_PROPERTY_DOUBLE

ID	Description	Property type
INDICATOR_MINIMUM	Minimum of the indicator window	double
INDICATOR_MAXIMUM	Maximum of the indicator window	double
INDICATOR_LEVELVALUE	Level value	double modifier = level number

ENUM_CUSTOMIND_PROPERTY_STRING

ID	Description	Property type
INDICATOR_SHORTNAME	Short indicator name	string
INDICATOR_LEVELTEXT	Level description	string modifier = level number

Example:

#property description "Relative Strength Index"
#property strict
#property indicator_separate_window
#property indicator_buffers 3
#property indicator_color1     clrDodgerBlue
//--- input parameters
input int InpRSIPeriod=14; // RSI Period
//--- buffers
double ExtRSIBuffer[];
double ExtPosBuffer[];
double ExtNegBuffer[];
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit(void)
  {
   string short_name;
//--- 2 additional buffers are used for calculations.
   IndicatorBuffers(3);
   SetIndexBuffer(0,ExtRSIBuffer);
   SetIndexBuffer(1,ExtPosBuffer);
   SetIndexBuffer(2,ExtNegBuffer);
//--- set levels
   IndicatorSetInteger(INDICATOR_LEVELS,2);
   IndicatorSetDouble(INDICATOR_LEVELVALUE,0,30);
   IndicatorSetDouble(INDICATOR_LEVELVALUE,1,70);
//--- set maximum and minimum for subwindow
   IndicatorSetDouble(INDICATOR_MINIMUM,0);
   IndicatorSetDouble(INDICATOR_MAXIMUM,100);
//--- indicator line
   SetIndexStyle(0,DRAW_LINE);
   SetIndexBuffer(0,ExtRSIBuffer);
//--- name for DataWindow and indicator subwindow label
   short_name="RSI("+string(InpRSIPeriod)+")";
   IndicatorShortName(short_name);
   SetIndexLabel(0,short_name);
//--- check for input
   if(InpRSIPeriod<2)
     {
      Print("Incorrect value for input variable InpRSIPeriod = ",InpRSIPeriod);
      return(INIT_FAILED);
     }
//---
   SetIndexDrawBegin(0,InpRSIPeriod);
//--- initialization done
   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//| Relative Strength Index                                          |
//+------------------------------------------------------------------+
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,pos;
   double diff;
//---
   if(Bars<=InpRSIPeriod || InpRSIPeriod<2)
      return(0);
//--- counting from 0 to rates_total
   ArraySetAsSeries(ExtRSIBuffer,false);
   ArraySetAsSeries(ExtPosBuffer,false);
   ArraySetAsSeries(ExtNegBuffer,false);
   ArraySetAsSeries(close,false);
//--- preliminary calculations
   pos=prev_calculated-1;
   if(pos<=InpRSIPeriod)
     {
      //--- first RSIPeriod values of the indicator are not calculated
      ExtRSIBuffer[0]=0.0;
      ExtPosBuffer[0]=0.0;
      ExtNegBuffer[0]=0.0;
      double sump=0.0;
      double sumn=0.0;
      for(i=1; i<=InpRSIPeriod; i++)
        {
         ExtRSIBuffer[i]=0.0;
         ExtPosBuffer[i]=0.0;
         ExtNegBuffer[i]=0.0;
         diff=close[i]-close[i-1];
         if(diff>0)
            sump+=diff;
         else
            sumn-=diff;
        }
      //--- calculate first visible value
      ExtPosBuffer[InpRSIPeriod]=sump/InpRSIPeriod;
      ExtNegBuffer[InpRSIPeriod]=sumn/InpRSIPeriod;
      if(ExtNegBuffer[InpRSIPeriod]!=0.0)
         ExtRSIBuffer[InpRSIPeriod]=100.0-(100.0/(1.0+ExtPosBuffer[InpRSIPeriod]/ExtNegBuffer[InpRSIPeriod]));
      else
        {
         if(ExtPosBuffer[InpRSIPeriod]!=0.0)
            ExtRSIBuffer[InpRSIPeriod]=100.0;
         else
            ExtRSIBuffer[InpRSIPeriod]=50.0;
        }
      //--- prepare the position value for main calculation
      pos=InpRSIPeriod+1;
     }
//--- the main loop of calculations
   for(i=pos; i<rates_total && !IsStopped(); i++)
     {
      diff=close[i]-close[i-1];
      ExtPosBuffer[i]=(ExtPosBuffer[i-1]*(InpRSIPeriod-1)+(diff>0.0?diff:0.0))/InpRSIPeriod;
      ExtNegBuffer[i]=(ExtNegBuffer[i-1]*(InpRSIPeriod-1)+(diff<0.0?-diff:0.0))/InpRSIPeriod;
      if(ExtNegBuffer[i]!=0.0)
         ExtRSIBuffer[i]=100.0-100.0/(1+ExtPosBuffer[i]/ExtNegBuffer[i]);
      else
        {
         if(ExtPosBuffer[i]!=0.0)
            ExtRSIBuffer[i]=100.0;
         else
            ExtRSIBuffer[i]=50.0;
        }
     }
//---
   return(rates_total);
  }

Drawing StylesEnvironment State