BidAskChannel

#property indicator_chart_window
#property indicator_buffers 2
#property indicator_color1 Black
#property indicator_color2 Black

//---- indicator parameters
//---- indicator buffers
double ExtMapBuffer1[];
double ExtMapBuffer2[];
//----
int ExtCountedBars=0;
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int init()
  {
   int    draw_begin;
   string short_name;
//---- drawing settings
   SetIndexStyle(0,DRAW_HISTOGRAM,0,1,indicator_color1);
   SetIndexStyle(1,DRAW_HISTOGRAM,0,1,indicator_color1);

   IndicatorDigits(MarketInfo(Symbol(),MODE_DIGITS));
//---- indicator short name
//   SetIndexDrawBegin(0,draw_begin);
//   SetIndexDrawBegin(0,draw_begin);
//---- indicator buffers mapping
   SetIndexBuffer(0,ExtMapBuffer1);
   SetIndexBuffer(1,ExtMapBuffer2);
   
//   int i;
//   for(i=0;i<Bars;i++)
//   {
//   ExtMapBuffer1[i]=Ask;
//   ExtMapBuffer2[i]=Bid;
//   }
  
//---- initialization done
   return(0);
  }
//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
int start()
  {
   ExtCountedBars=IndicatorCounted();
//---- check for possible errors
   if (ExtCountedBars<0) return(-1);
//---- last counted bar will be recounted
   if (ExtCountedBars>0) ExtCountedBars--;
//----
   int i;
   for(i=0;i<Bars-ExtCountedBars;i++)
   {
   ExtMapBuffer1[i]=High[i]+Ask-Bid;
   ExtMapBuffer2[i]=Low[i];
   }
//---- done
   return(0);
  }