mql5/Indicators/MyIndicators/StandardDeviationChannel.mq5

//+------------------------------------------------------------------+
//|                                      StandardDeviationChannel.mq5|
//|                      Copyright 2025, xxxxxxxx                    |
//|                                                                  |
//+------------------------------------------------------------------+
#property copyright "Copyright 2025, xxxxxxxx"
#property link      ""
#property version   "1.00"
#property description "Draws a Standard Deviation Channel (based on Linear Regression)."
#property indicator_chart_window
#property indicator_buffers 0
#property indicator_plots   0

//--- Input Parameters ---
input int    InpRegressionPeriod = 100;   // Period for the regression calculation
input double InpDeviations       = 2.0;     // Number of standard deviations for the channel
input group  "Channel Extensions"
input bool   InpRayRight         = false;   // Extend channel to the right
input bool   InpRayLeft          = false;   // Extend channel to the left

//--- Global Variables ---
int       g_ExtPeriod;
double    g_ExtDeviations;
string    g_channel_name;
datetime  g_last_update_time;

//+------------------------------------------------------------------+
//| Custom indicator initialization function.                        |
//+------------------------------------------------------------------+
int OnInit()
  {
   g_ExtPeriod      = (InpRegressionPeriod < 2) ? 2 : InpRegressionPeriod;
   g_ExtDeviations  = (InpDeviations <= 0) ? 2.0 : InpDeviations;

   g_channel_name = "StdDevChannel_" + IntegerToString(ChartID()) + "_" + IntegerToString(GetTickCount());
   g_last_update_time = 0;

   IndicatorSetString(INDICATOR_SHORTNAME, StringFormat("StdDev Ch(%d, %.1f)", g_ExtPeriod, g_ExtDeviations));

   EventSetTimer(1);

   return(INIT_SUCCEEDED);
  }

//+------------------------------------------------------------------+
//| Custom indicator deinitialization function.                      |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
   EventKillTimer();
   ObjectDelete(0, g_channel_name);
   ChartRedraw();
  }

//+------------------------------------------------------------------+
//| Timer event handler.                                             |
//+------------------------------------------------------------------+
void OnTimer()
  {
   UpdateChannel();
  }

//+------------------------------------------------------------------+
//| Main calculation 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[])
  {
   if(rates_total < g_ExtPeriod)
      return(0);

   datetime last_bar_time = time[rates_total - 1];
   if(last_bar_time > g_last_update_time)
     {
      UpdateChannel();
      g_last_update_time = last_bar_time;
     }

   return(rates_total);
  }

//+------------------------------------------------------------------+
//| Updates the position and properties of the channel.              |
//+------------------------------------------------------------------+
void UpdateChannel()
  {
   if(Bars(_Symbol, _Period) < g_ExtPeriod)
      return;

   datetime time1 = iTime(_Symbol, _Period, g_ExtPeriod - 1);
   datetime time2 = iTime(_Symbol, _Period, 0);

   if(ObjectFind(0, g_channel_name) < 0)
     {
      if(!ObjectCreate(0, g_channel_name, OBJ_STDDEVCHANNEL, 0, time1, 0, time2, 0))
        {
         Print("Error creating std dev channel object: ", GetLastError());
         return;
        }

      ObjectSetInteger(0, g_channel_name, OBJPROP_COLOR, clrRed);
      ObjectSetInteger(0, g_channel_name, OBJPROP_STYLE, STYLE_SOLID);
      ObjectSetInteger(0, g_channel_name, OBJPROP_FILL, false);
      ObjectSetInteger(0, g_channel_name, OBJPROP_SELECTABLE, false);
     }

   ObjectSetInteger(0, g_channel_name, OBJPROP_TIME, 0, time1);
   ObjectSetInteger(0, g_channel_name, OBJPROP_TIME, 1, time2);
   ObjectSetDouble(0, g_channel_name, OBJPROP_DEVIATION, g_ExtDeviations);
   ObjectSetInteger(0, g_channel_name, OBJPROP_RAY_RIGHT, InpRayRight);
   ObjectSetInteger(0, g_channel_name, OBJPROP_RAY_LEFT, InpRayLeft);

// The OBJ_STDDEVCHANNEL object uses PRICE_CLOSE and its own internal period for the regression
// We don't need to set OBJPROP_PERIOD as it's implicitly handled by the time coordinates.

   ChartRedraw();
  }
//+------------------------------------------------------------------+
//+------------------------------------------------------------------+