//+------------------------------------------------------------------+
//|                                             Gann_Multi_Trend.mq4 |
//|                      Copyright © 2011, Mikhail Pashnin (raxxla). |
//|                                        http://www.mql4.com       |
//+------------------------------------------------------------------+
#property copyright "Copyright © 2011, Mikhail Pashnin."
#property link      "http://www.mql4.com"

#property indicator_chart_window
#property indicator_buffers 6
#property indicator_color1 Red
#property indicator_color2 Green
#property indicator_color3 Red
#property indicator_color4 Green
#property indicator_color5 Red
#property indicator_color6 Green

extern int Bars1 = 1;
extern int Bars2 = 2;
extern int Bars3 = 3;

//---- buffers
double Buffer1Up[];
double Buffer1Dn[];
double Buffer2Up[];
double Buffer2Dn[];
double Buffer3Up[];
double Buffer3Dn[];
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int init()
  {
//---- indicators
   SetIndexStyle(0,DRAW_LINE, STYLE_SOLID, 3);
   SetIndexBuffer(0,Buffer3Up);
   SetIndexStyle(1,DRAW_LINE, STYLE_SOLID, 3);
   SetIndexBuffer(1,Buffer3Dn);

   SetIndexStyle(2,DRAW_LINE, STYLE_SOLID, 2);
   SetIndexBuffer(2,Buffer2Up);
   SetIndexStyle(3,DRAW_LINE, STYLE_SOLID, 2);
   SetIndexBuffer(3,Buffer2Dn);

   SetIndexStyle(4,DRAW_LINE, STYLE_SOLID, 1);
   SetIndexBuffer(4,Buffer1Up);
   SetIndexStyle(5,DRAW_LINE, STYLE_SOLID, 1);
   SetIndexBuffer(5,Buffer1Dn);
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| Custom indicator deinitialization function                       |
//+------------------------------------------------------------------+
int deinit()
  {
//----
   
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int start()
  {
//----
   if(Bars<=Bars1) return(0);
     
   int counted_bars = IndicatorCounted();
   if(counted_bars < 0)  return(-1);
   if(counted_bars > 0)   counted_bars--;
   int limit = Bars - counted_bars;
   if(counted_bars==0) limit-=1+1+MathMax(Bars3,MathMax(Bars1,Bars2));
      
   int pos=limit-Bars3;
   if(Bars1>0)
   { 
      while(pos>=0)
      {
         SetBufferData(Buffer1Up, Buffer1Dn, Bars1, pos);
         pos--;
      }
   }

   pos=limit-Bars1;
   if(Bars2>0)
   { 
      while(pos>=0)
      {
         SetBufferData(Buffer2Up, Buffer2Dn, Bars2, pos);
         pos--;
      }
   }

   pos=limit-Bars1;
   if(Bars3>0)
   { 
      while(pos>=0)
      {
         SetBufferData(Buffer3Up, Buffer3Dn, Bars3, pos);
         pos--;
      }
   }
   
//----
   return(0);
  }
//+------------------------------------------------------------------+

void SetBufferData(double& up[], double& dn[], int bars, int index)
{
   double max = High[index+bars];
   double min = Low[index+bars];
      
   for(int i=1; i<bars; i++)
   {
      max = MathMax(max, High[index+bars+i]);  
      min = MathMin(max, Low[index+bars+i]);
   }
   
   if(High[index]>max && Low[index]>min)
   {
      dn[index]=EMPTY_VALUE;
      up[index]=High[index];
      up[index+1]=High[index+1];
      
      return;
   }

   if(Low[index]<min && High[index]<max)
   {
      dn[index]=Low[index];
      dn[index+1]=Low[index+1];
      up[index]=EMPTY_VALUE;
      
      return;
   }

   if(Low[index]>min && High[index]<max)
   {
      dn[index]=dn[index+1];
      up[index]=up[index+1];
      
      return;
   }

   if(Low[index]<min && High[index]>max)
   {
      dn[index]=Low[index];
      up[index]=High[index];
      
      return;
   }
}