fractal channel
//+------------------------------------------------------------------+
//|                                                  SHI_Channel.mq4 |
//|                                 Copyright © 2004, Shurka & Kevin |
//|                                                                  |
//+------------------------------------------------------------------+
#property copyright "Copyright © 2004, Shurka & Kevin"
#property link      ""
#property indicator_chart_window
#property indicator_buffers 1
#property indicator_color1 Red
double ExtMapBuffer1[];
//---- input parameters
extern int       AllBars=240;
extern int       BarsForFract=0;
int CurrentBar=0;
double Step=0;
int B1=-1,B2=-1;
int UpDown=0;
double P1=0,P2=0,PP=0;
int i=0,AB=300,BFF=0;
int ishift=0;
double iprice=0;
datetime T1,T2;
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int init()
  {
//---- indicators
   SetIndexStyle(0,DRAW_ARROW);
   SetIndexArrow(0,164);
   SetIndexBuffer(0,ExtMapBuffer1);
   SetIndexEmptyValue(0,0.0);
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| Custor indicator deinitialization function                       |
//+------------------------------------------------------------------+
int deinit()
  {
//---- 
   
//----
   return(0);
  }
void DelObj()
{
ObjectDelete("TL1");
ObjectDelete("TL2");
ObjectDelete("MIDL");
}
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int start()
  {
   int    counted_bars=IndicatorCounted();
//---- 
if ((AllBars==0) || (Bars<AllBars)) AB=Bars; else AB=AllBars; 
if (BarsForFract>0) 
BFF=BarsForFract; 
else
{
switch (Period())
{
case 1: BFF=12; break;
case 5: BFF=48; break;
case 15: BFF=24; break;
case 30: BFF=24; break;
case 60: BFF=12; break;
case 240: BFF=15; break;
case 1440: BFF=10; break;
case 10080: BFF=6; break;
default: DelObj(); return(-1); break;
}
}
CurrentBar=2; 
B1=-1; B2=-1; UpDown=0;
while(((B1==-1) || (B2==-1)) && (CurrentBar<AB))
{
if((UpDown<1) && (CurrentBar==Lowest(Symbol(),Period(),MODE_LOW,BFF*2+1,CurrentBar-BFF))) 
{
if(UpDown==0) { UpDown=-1; B1=CurrentBar; P1=Low[B1]; }
else { B2=CurrentBar; P2=Low[B2];}
}
if((UpDown>-1) && (CurrentBar==Highest(Symbol(),Period(),MODE_HIGH,BFF*2+1,CurrentBar-BFF))) 
{
if(UpDown==0) { UpDown=1; B1=CurrentBar; P1=High[B1]; }
else { B2=CurrentBar; P2=High[B2]; }
}
CurrentBar++;
}
if((B1==-1) || (B2==-1)) {DelObj(); return(-1);} 
Step=(P2-P1)/(B2-B1);
P1=P1-B1*Step; B1=0;
ishift=0; iprice=0;
if(UpDown==1)
{ 
PP=Low[2]-2*Step;
for(i=3;i<=B2;i++) 
{
if(Low<PP+Step*i) { PP=Low-i*Step; }
}
if(Low[0]<PP) {ishift=0; iprice=PP;}
if(Low[1]<PP+Step) {ishift=1; iprice=PP+Step;}
if(High[0]>P1) {ishift=0; iprice=P1;}
if(High[1]>P1+Step) {ishift=1; iprice=P1+Step;}
} 
else
{ 
PP=High[2]-2*Step;
for(i=3;i<=B2;i++) 
{
if(High>PP+Step*i) { PP=High-i*Step;}
}
if(Low[0]<P1) {ishift=0; iprice=P1;}
if(Low[1]<P1+Step) {ishift=1; iprice=P1+Step;}
if(High[0]>PP) {ishift=0; iprice=PP;}
if(High[1]>PP+Step) {ishift=1; iprice=PP+Step;}
}
P2=P1+AB*Step;
T1=Time[B1]; T2=Time[AB];
if(iprice!=0) ExtMapBuffer1[ishift]=iprice;
DelObj();
ObjectCreate("TL1",OBJ_TREND,0,T2,PP+Step*AB,T1,PP); 
ObjectSet("TL1",OBJPROP_COLOR,ForestGreen); 
ObjectSet("TL1",OBJPROP_WIDTH,2); 
ObjectSet("TL1",OBJPROP_STYLE,STYLE_SOLID); 
ObjectCreate("TL2",OBJ_TREND,0,T2,P2,T1,P1); 
ObjectSet("TL2",OBJPROP_COLOR,ForestGreen); 
ObjectSet("TL2",OBJPROP_WIDTH,2); 
ObjectSet("TL2",OBJPROP_STYLE,STYLE_SOLID); 
ObjectCreate("MIDL",OBJ_TREND,0,T2,(P2+PP+Step*AB)/2,T1,(P1+PP)/2);
ObjectSet("MIDL",OBJPROP_COLOR,ForestGreen); 
ObjectSet("MIDL",OBJPROP_WIDTH,1); 
ObjectSet("MIDL",OBJPROP_STYLE,STYLE_DOT); 
//----
   return(0);
  }
//+------------------------------------------------------------------+