StdDev Histogram

ÿþ//+------------------------------------------------------------------+

//|                                             StdDev Histogram.mq5 |

//|                              Copyright © 2020, Vladimir Karputov |

//|                     https://www.mql5.com/ru/market/product/43516 |

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

#property copyright "Copyright © 2020, Vladimir Karputov"

#property link      "https://www.mql5.com/ru/market/product/43516"

#property version   "1.000"

#property indicator_separate_window

#property indicator_buffers 2

#property indicator_plots   1

//--- plot StdDev

#property indicator_label1  "StdDev"

#property indicator_type1   DRAW_COLOR_HISTOGRAM

#property indicator_color1  clrRed,clrBlue

#property indicator_style1  STYLE_SOLID

#property indicator_width1  2

//--- input parameters

input group             "StdDev"

input int                  Inp_StdDev_ma_period    = 12;          // StdDev:averaging period

input int                  Inp_StdDev_ma_shift     = 0;           // StdDev:horizontal shift

input ENUM_MA_METHOD       Inp_StdDev_ma_method    = MODE_SMA;    // StdDev:smoothing type

input ENUM_APPLIED_PRICE   Inp_StdDev_applied_price= PRICE_CLOSE; // StdDev:type of price

//--- indicator buffers

double   StdDevBuffer[];

double   StdDevColors[];

//---

int      handle_iStdDev;                  // variable for storing the handle of the iStdDev indicator

int      bars_calculated=0;               // we will keep the number of values in the Standard Deviation indicator

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

//| Custom indicator initialization function                         |

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

int OnInit()

  {

//--- indicator buffers mapping

   SetIndexBuffer(0,StdDevBuffer,INDICATOR_DATA);

   SetIndexBuffer(1,StdDevColors,INDICATOR_COLOR_INDEX);

//--- set shift of each line

   PlotIndexSetInteger(0,PLOT_SHIFT,Inp_StdDev_ma_shift);

//--- set index label

   PlotIndexSetString(0,PLOT_LABEL,"StdDev("+IntegerToString(Inp_StdDev_ma_period)+")");

//--- create handle of the indicator iStdDev

   handle_iStdDev=iStdDev(Symbol(),Period(),Inp_StdDev_ma_period,

                          Inp_StdDev_ma_shift,Inp_StdDev_ma_method,Inp_StdDev_applied_price);

//--- if the handle is not created

   if(handle_iStdDev==INVALID_HANDLE)

     {

      //--- tell about the failure and output the error code

      PrintFormat("Failed to create handle of the iStdDev indicator for the symbol %s/%s, error code %d",

                  Symbol(),

                  EnumToString(Period()),

                  GetLastError());

      //--- the indicator is stopped early

      return(INIT_FAILED);

     }

//---

   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(rates_total<Inp_StdDev_ma_period+Inp_StdDev_ma_shift)

      return(0);

//--- number of values copied from the iStdDev indicator

   int values_to_copy;

//--- determine the number of values calculated in the indicator

   int calculated=BarsCalculated(handle_iStdDev);

   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 iStdDev 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 iStdDevBuffer array is greater than the number of values in the iStdDev 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 array with values of the Standard Deviation indicator

//--- if FillArrayFromBuffer returns false, it means the information is nor ready yet, quit operation

   if(!FillArrayFromBuffer(StdDevBuffer,Inp_StdDev_ma_shift,handle_iStdDev,values_to_copy))

      return(0);

//--- memorize the number of values in the Standard Deviation indicator

   bars_calculated=calculated;

//--- main loop

   int limit=prev_calculated-1;

   if(prev_calculated==0)

     {

      StdDevColors[0]=0;

      limit=1;

     }

   for(int i=limit; i<rates_total; i++)

     {

      if(StdDevBuffer[i]<StdDevBuffer[i-1])

         StdDevColors[i]=0.0;

      else

         StdDevColors[i]=1.0;

     }

//--- return the prev_calculated value for the next call

   return(rates_total);

  }

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

//| Filling indicator buffers from the iStdDev indicator             |

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

bool FillArrayFromBuffer(double &std_buffer[],  // indicator buffer of the Standard Deviation line

                         int std_shift,         // shift of the Standard Deviation line

                         int ind_handle,        // handle of the iStdDev indicator

                         int amount             // number of copied values

                        )

  {

//--- reset error code

   ResetLastError();

//--- fill a part of the iStdDevBuffer array with values from the indicator buffer that has 0 index

   if(CopyBuffer(ind_handle,0,-std_shift,amount,std_buffer)<0)

     {

      //--- if the copying fails, tell the error code

      PrintFormat("Failed to copy data from the iStdDev 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_iStdDev!=INVALID_HANDLE)

      IndicatorRelease(handle_iStdDev);

  }

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