[Hassam]

MQL5 is a quirky language. Maybe I am not very good at it. Anyway it is no comparison to Python and C#. These two languages are very powerful. I have further improved the above code and made sure that the macdHandle is calculated before the indicator gets displayed. This is what was happening. On first rendition, the indicator was given wrong lines. So I looked into the problem and modified the code to make sure that the data is properly calculated before it is displayed. Below is the modified code:

Code:

//+------------------------------------------------------------------+
//|                                                   MACD_Color.mq5 |
//|                                     Copyright 2019, Ahmad Hassam |
//|                                       https://www.doubledoji.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2019, Ahmad Hassam"
#property link      "https://www.doubledoji.com"
#property version   "1.00"
#property description "Moving Average Convergence/Divergence"
#property indicator_separate_window
#property indicator_buffers 4
#property indicator_plots   2



//--- plot MACD HISTOGRAM
#property indicator_label1  "MACD"
#property indicator_type1   DRAW_COLOR_HISTOGRAM
#property indicator_color1  clrLightGreen, clrDarkGreen, clrPink, clrRed   
#property indicator_style1  STYLE_SOLID
#property indicator_width1  3


//--- plot MACD Signal
#property indicator_label2  "Signal"
#property indicator_type2   DRAW_LINE
#property indicator_color2  clrRed
#property indicator_style2  STYLE_SOLID
#property indicator_width2  2

//--- input parameters
input int      fastEMA=12;
input int      slowEMA=26;
input int      signalPeriod=9;
input ENUM_APPLIED_PRICE MAPrice = PRICE_CLOSE;


//--- indicator buffers
double         macd_main[];   //MACD Histogram
double         macd_color[];  //MACD Histogram bar colors
double         macd_signal[]; //MACD Signal
double         macd_signal_color[];

//--declare MACD Handle
int macdHandle;



//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
  {
//--- indicator subwindow label
IndicatorSetString(INDICATOR_SHORTNAME,
"MACD("+string(fastEMA)+", "+string(slowEMA)+","+string(signalPeriod)+")"); 

//--- indicator buffers mapping
//--- Bind the color buffer immediately below the data buffer
   SetIndexBuffer(0,macd_main,INDICATOR_DATA);
   ArraySetAsSeries(macd_main,true);
   SetIndexBuffer(1,macd_color,INDICATOR_COLOR_INDEX);
   ArraySetAsSeries(macd_color,true);
   SetIndexBuffer(2,macd_signal,INDICATOR_DATA);
   ArraySetAsSeries(macd_signal,true);
   SetIndexBuffer(3,macd_signal_color,INDICATOR_COLOR_INDEX);
   ArraySetAsSeries(macd_signal_color,true);
   
//--Initialize the MACD
   macdHandle = iMACD(_Symbol,_Period,fastEMA,
   slowEMA,signalPeriod, MAPrice);


 
   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 < signalPeriod)
      return(0);
//--- not all data may be calculated
   int calculated=BarsCalculated(macdHandle);
   if(calculated < rates_total)
     {
      Print("Not all data of macdHandle is calculated (",calculated," bars). Error ",GetLastError());
      return(0);
     }
   
     
   


   int end;
   if(prev_calculated < rates_total)
      end=rates_total - prev_calculated - 1;
   else
      end = 1;
     
   
     
//--- Data preparation

   if(IsStopped()) // checking for stop flag
      return(0);
   if(CopyBuffer(macdHandle,0,0,end+1,macd_main)<=0)
     {
      Print("Getting macd_main is failed! Error ",GetLastError());
      return(0);
     }
//--- get macd_signal buffer
   if(IsStopped()) // checking for stop flag
      return(0);
   if(CopyBuffer(macdHandle,1,0,end+1,macd_signal)<=0)
     {
      Print("Getting macd_signal is failed! Error ",GetLastError());
      return(0);
     } 
           
       
 

//--- 

   
   for(int i = 0; i < end; i++)     
 
   {
   
 

//--color code the MACD bars
     
   if( macd_main[i] < 0 && macd_main[i] > macd_main[i+1])macd_color[i]=0;
   else if( macd_main[i] > 0 && macd_main[i] > macd_main[i+1])macd_color[i]=1;   
   else if( macd_main[i] > 0 && macd_main[i] < macd_main[i+1])macd_color[i]=2;
   else if( macd_main[i] < 0 && macd_main[i] < macd_main[i+1])macd_color[i]=3;

   
   
  }   
   
   
   
//--- return value of prev_calculated for next call
   return(rates_total);
  }
 
//+------------------------------------------------------------------+
//| Indicator deinitialization function                              |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
   if(macdHandle!=INVALID_HANDLE)
      IndicatorRelease(macdHandle);
//--- clear the chart after deleting the indicator
   Comment("");
  }

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