mql5/Indicators/Free Indicators/Donchian Channel.mq5

<EFBFBD><EFBFBD>//+------------------------------------------------------------------+

//|                                             Donchian Channel.mq5 |

//|                              Copyright 2009-2025, MetaQuotes Ltd |

//|                                             https://www.mql5.com |

//+------------------------------------------------------------------+

#property copyright   "2009-2025, MetaQuotes Ltd"

#property link        "http://www.mql5.com"

#property description "Donchian Channel"

//---

#property indicator_chart_window

#property indicator_buffers 3

#property indicator_plots   3

#property indicator_type1   DRAW_LINE

#property indicator_color1  clrBlue

#property indicator_type2   DRAW_LINE

#property indicator_color2  clrGray

#property indicator_type3   DRAW_LINE

#property indicator_color3  clrRed

//--- labels

#property indicator_label1  "Upper Donchian"

#property indicator_label2  "Middle Donchian"

#property indicator_label3  "Lower Donchian"



//--- input parameter

input int  InpDonchianPeriod=20;    // period of the channel

input bool InpShowLabel     =true;  // show price of the level



//--- indicator buffers

double    ExtUpBuffer[];

double    ExtMdBuffer[];

double    ExtDnBuffer[];



//--- unique prefix for indicator objects

string ExtPrefixUniq;

//--- current chart scale

long   ExtChartScale=2;

//--- flag indicating that the indicator is running on the built-in VPS

bool   ExtBuiltOnVPS=false;

bool   ExtShowLabel=false;

//+------------------------------------------------------------------+

//| Custom indicator initialization function                         |

//+------------------------------------------------------------------+

int OnInit()

  {

//--- if the indicator is running on the built-in VPS, price labels should not be shown

   if(!TerminalInfoInteger(TERMINAL_VPS))

      ExtShowLabel=InpShowLabel;  

      

//--- define buffers

   SetIndexBuffer(0, ExtUpBuffer);

   SetIndexBuffer(1, ExtMdBuffer);

   SetIndexBuffer(2, ExtDnBuffer);



//--- set a 1-bar offset for each line

   PlotIndexSetInteger(0, PLOT_SHIFT, 1);

   PlotIndexSetInteger(1, PLOT_SHIFT, 1);

   PlotIndexSetInteger(2, PLOT_SHIFT, 1);



//--- indicator name

   IndicatorSetString(INDICATOR_SHORTNAME, "Donchian Channel");

//--- number of digits of indicator value

   IndicatorSetInteger(INDICATOR_DIGITS, _Digits);



//--- prepare prefix for objects

   string number=StringFormat("%I64d", GetTickCount64());

   ExtPrefixUniq=StringSubstr(number, StringLen(number)-4);

   ExtPrefixUniq=ExtPrefixUniq+"_DN";

   Print("Indicator \"Donchian Channels\" started, prefix=", ExtPrefixUniq);



   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[])

  {

//--- if the indicator has previously been calculated, start from the bar preceding the last one

   int start=prev_calculated-1;