The Volume Weighted Average Price (VWAP) is a benchmark indicator used by traders, particularly in intraday analysis, to determine the average price a security has traded at throughout a period, based on both price and volume. It provides a much more accurate picture of the "true" average price by giving more weight to price levels with higher trading volume.
Our `VWAP_Pro` implementation is a highly flexible, professional version that offers multiple reset options:
* Standard **Daily, Weekly, or Monthly** periods.
* A **Timezone-Shifted Daily** period, allowing the "day" to be anchored to a specific exchange's midnight (e.g., NYSE) regardless of broker server time.
* A fully **Custom Session** period defined by a specific start and end time.
The indicator also allows the calculation to be based on either **standard** or **Heikin Ashi** price data.
The entire calculation logic is encapsulated within a reusable `CVWAPCalculator` class. This engine uses an elegant, object-oriented inheritance model (`CVWAPCalculator` and `CVWAPCalculator_HA`) to support both standard and Heikin Ashi data sources without code duplication.
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 cumulative variables (`m_cumulative_tpv`, `m_cumulative_vol`) 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.
* **Clean Gapped-Line Drawing:** To provide a clear visual separation between periods, the indicator uses a **"double buffer" technique**. It plots odd-numbered periods and even-numbered periods on two separate, overlapping plot buffers. This creates a distinct visual gap at each reset point.
* **Intelligent Volume Handling:** The indicator automatically detects if the selected instrument provides **Real Volume**. If a user requests Real Volume on a symbol where it's unavailable (like Forex/CFDs), the indicator will fail to load and print an informative error message.
*`Reset Period (`InpResetPeriod`): The period at which the VWAP calculation resets.
*`PERIOD_SESSION`: Resets daily. The start of the "day" can be adjusted with the timezone shift parameter.
*`PERIOD_WEEK`: Resets at the start of each week (typically Monday 00:00 broker time).
*`PERIOD_MONTH`: Resets at the start of each month.
*`PERIOD_CUSTOM_SESSION`: Resets based on the custom start/end times defined below.
*`Session Timezone Shift (`InpSessionTimezoneShift`): **Only applies if`Reset Period` is `PERIOD_SESSION`**. This allows you to align the daily reset with a specific market's midnight. Enter the time difference in hours between your broker's server and the desired timezone (e.g., if your broker is UTC+3 and you want to align with NYSE which is UTC-4 in summer, the shift is -7).
* **Custom Session (if selected above):**
*`Custom Session Start (`InpCustomSessionStart`): **Only applies if`Reset Period` is `PERIOD_CUSTOM_SESSION`**. The start time (HH:MM) for the custom VWAP calculation period.
*`Custom Session End (`InpCustomSessionEnd`): **Only applies if`Reset Period` is `PERIOD_CUSTOM_SESSION`**. The end time (HH:MM) for the custom VWAP calculation period.
* **Calculation Settings:**
*`Volume Type (`InpVolumeType`): Allows the user to select between`Tick Volume` and `Real Volume`.
*`Candle Source (`InpCandleSource`): Allows the user to select the candle type for the Typical Price calculation (`Standard` or `Heikin Ashi`).
* **Benchmark for "Fair Value":** The VWAP is often considered the "true" average price for the period. Price action above the VWAP is generally considered bullish for the session, while price action below is bearish.
* **Dynamic Support and Resistance:** The VWAP line itself acts as a powerful, dynamic level of support or resistance during the trading session.
* **Mean Reversion:** A significant deviation of the price from the VWAP often leads to a reversion back towards it.
* **Execution Benchmark:** Institutional traders often use the VWAP to gauge the quality of their trade executions. Buying below the VWAP or selling above it is considered a good execution.
