Visible buffers

Overview

To display indicator values on the chart in Forex Tester Online, you need to use buffers. Buffers store the calculated values and define how they should be visualized (e.g., lines, histograms, dots).

Each buffer is created as a TIndexBuffer and configured through API calls.

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Step-by-Step Guide

1. Declare the Buffer

All buffers must be declared as class fields using the TIndexBuffer type.

public SSMA!: TIndexBuffer;

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2. Create the Buffer in Init()

Create the buffer instance using the CreateIndexBuffer() method.

this.SSMA = this.api.CreateIndexBuffer();

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3. Register the Number of Buffers

Tell the API how many buffers you plan to use. In this case — one:

this.api.IndicatorBuffers(1);

This must be called before setting buffer styles or assignments.

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4. Bind the Buffer to an Index

Each buffer must be assigned a unique index:

this.api.SetIndexBuffer(0, this.SSMA);

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5. Configure the Buffer

You can now customize how the buffer will appear on the chart:

this.api.SetIndexLabel(0, "SSMA"); // Label shown in the legend
this.api.SetIndexStyle(0, TDrawStyle.LINE, TPenStyle.SOLID, 1, "#FF0000"); // Style
this.api.SetIndexDrawBegin(0, this.Period.value - 1 + this.Shift.value); // Starting bar

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Full Example

import { TIndexBuffer } from "forex-tester-custom-indicator-api";

export default class MovingAverage extends IndicatorImplementation {
  // Declare parameters as class fields
  public Period!: TOptValue_number;
  public Shift!: TOptValue_number;
  public SSMA!: TIndexBuffer;

  public Init(): void {
    // Create parameters
    this.Period = this.api.createTOptValue_number(8);
    this.Shift = this.api.createTOptValue_number(0);

    // Create and configure the buffer
    this.SSMA = this.api.CreateIndexBuffer();
    this.api.IndicatorBuffers(1);
    this.api.SetIndexBuffer(0, this.SSMA);
    this.api.SetIndexLabel(0, "SSMA");
    this.api.SetIndexStyle(0, TDrawStyle.LINE, TPenStyle.SOLID, 1, "#FF0000");
    this.api.SetIndexDrawBegin(0, this.Period.value - 1 + this.Shift.value);
  }
}

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Notes

• Each buffer must be declared, created, and registered properly to be visible on the chart.

• Indices must be unique and zero-based (0, 1, 2, etc.).

• You can use multiple buffers to display several lines or visual elements.