mql5/Indicators/MyIndicators/Supertrend_Pro.md

Supertrend Pro

1. Summary (Introduction)

The Supertrend indicator, developed by Olivier Seban, is a simple yet effective trend-following indicator. Plotted directly on the price chart, the Supertrend line changes color and position based on the market's trend, acting as a dynamic level of support or resistance.

Our Supertrend_Pro implementation is a unified, professional version that combines three distinct calculation methodologies into a single, flexible indicator:

1. Standard: Classic Supertrend using standard price data.
2. HA-Hybrid: A smoothed Supertrend based on Heikin Ashi prices, with channel width based on standard, real-market ATR.
3. HA-Pure: A fully smoothed Supertrend where both the trend calculation and the ATR are based on Heikin Ashi data.

2. Mathematical Foundations and Calculation Logic

The Supertrend indicator combines a measure of volatility (Average True Range - ATR) with a central price point to construct upper and lower bands.

Required Components

• ATR (Average True Range): A measure of market volatility.
• Factor (Multiplier): A user-defined multiplier that adjusts the sensitivity.
• Median Price (hl2): The central point for the bands, calculated as (High + Low) / 2.

Calculation Steps (Algorithm)

1. Calculate the Average True Range (ATR).
2. Calculate the Basic Upper and Lower Bands.
3. Calculate the Final Upper and Lower Bands using the "stair-step" logic.
4. Determine the Trend Direction by comparing the closing price to the opposite band.
5. Plot the Supertrend Line: Plot the Final Lower Band in an uptrend, and the Final Upper Band in a downtrend.

3. MQL5 Implementation Details

Our MQL5 implementation follows a modern, component-based, object-oriented design.

• Component-Based Design: The Supertrend_Calculator reuses our existing, standalone ATR_Calculator.mqh module, ensuring the ATR component is always our robust, definition-true Wilder's ATR.

• Optimized Incremental Calculation: Unlike basic implementations that recalculate the entire history on every tick, this indicator employs an intelligent incremental algorithm.

  • It utilizes the prev_calculated state to determine the exact starting point for updates.
  • Persistent State: The internal buffers for the recursive "stair-step" logic (m_upper, m_lower, m_trend) persist their state between ticks. This allows the calculation to continue seamlessly from the last known value without re-processing the entire history.
  • This results in O(1) complexity per tick, ensuring instant updates and zero lag, even on charts with extensive history.

• Object-Oriented Logic: An elegant inheritance model (CSupertrendCalculator and CSupertrendCalculator_HA) allows the indicator to seamlessly switch between standard and Heikin Ashi price data for its core logic.

• Clean Gapped-Line Drawing: To provide a clear visual separation at trend changes, the indicator uses a "double buffer" technique. It plots uptrend and downtrend segments on two separate, overlapping plot buffers. This creates a distinct visual gap when the trend flips, accurately representing the signal without drawing misleading connecting lines.

4. Parameters

• ATR Period (InpAtrPeriod): The lookback period for the ATR calculation. Default is 10.
• Factor (InpFactor): The multiplier applied to the ATR value. Default is 3.0.
• Candle Source (InpCandleSource): Determines the source for the Supertrend's price component ((High+Low)/2 and Close).
• ATR Source (InpAtrSource): Determines the source for the ATR calculation (Standard or Heikin Ashi), allowing you to create "Hybrid" or "Pure" HA versions.

5. Usage and Interpretation

• Trend Identification: A green line below the price indicates an uptrend. A red line above the price indicates a downtrend.
• Trailing Stop-Loss: The indicator is exceptionally well-suited for use as a trailing stop-loss.
• Trade Signals: A change in the indicator's color can be interpreted as a trade signal.
• Caution: Like all trend-following indicators, Supertrend is most effective in trending markets. In sideways or ranging markets, it can produce frequent false signals ("whipsaws").