Indicators with dots and arrows

It is often necessary to write an indicator, which will mark some important point on the price chart with a dot or an arrow, e.g. an oscillator reaching certain level or a moving average crossing.

Personally, I like such indicators very much, because they don’t clutter up the chart and allow to indicate precisely the place of a certain condition occuring, which is not so easy to read from the oscillator window.

Implementation of such indicator is very simple and I will show you the template below.

#property indicator_chart_window

// we set the number of buffers and indicator buffers colors
#property indicator_buffers 2
#property indicator_color1 RoyalBlue
#property indicator_color2 Red

// it's good to make our dots bigger to see them better
#property indicator_width1 2
#property indicator_width2 2

// we define indicator arrays
double long[];
double short[];

// extern variable to set the distance of the dot from the candle
extern int margin=20;

int init() {

 // we set the properties of indicator buffers

 SetIndexBuffer(0,long);
 SetIndexStyle(0,DRAW_ARROW,0,1);
 SetIndexArrow(0,159); // 159 is a dot code

 SetIndexBuffer(1,short);
 SetIndexStyle(1,DRAW_ARROW,0,1);
 SetIndexArrow(1,159);

 return(0);
}

int start() {

 // we start checking conditions for the last 500 periods

 for(int i=0;i<500;i++) {

  if(........) { // long condition (blue dot under the candle)
   long[i]=Low[i]-margin*Point;
  } else {
   long[i]=EMPTY_VALUE;
  }

  if(........) { // short condition (red dot under the candle)
   short[i]=High[i]+margin*Point;
  } else {
   short[i]=EMPTY_VALUE;
  }

 }

 return(0);
}

Arrow drawing code looks similiar, but we set the second argument of a SetIndexArrow function to 241 for long and to 242 for short.