refactor(indicators): Added option for Original Ehlers Calculation

Indicators/MyIndicators/Authors/Ehlers/2_Oscillators/CG_Oscillator_Pro.md

@@ -6,13 +6,16 @@ The Center of Gravity (CG) Oscillator, developed by John Ehlers, is a unique ind
 
 By treating the prices over a lookback window as weights on a ruler, the indicator calculates the "balance point" of the recent price action. Ehlers observed that this balance point moves in opposition to the price. By inverting the result, he created a smooth oscillator that is **in-phase with the price swings**, enabling very early identification of potential reversals.
 
+**New in Version 2.10:** The indicator now supports two calculation modes:
+
+1. **Original Mode:** Delivers the raw, negative values exactly as described in Ehlers' original paper.
+2. **Pro Mode (Default):** Automatically centers the oscillator around **0.0**, making it easier to read without changing the signal geometry.
+
 The indicator plots two lines, forming a complete crossover system:
 
 * **CG Line (red):** The main Center of Gravity oscillator value.
 * **Signal Line (blue):** The CG line delayed by one bar, which acts as a trigger line.
 
-The result is a fast, smooth, and responsive oscillator for timing entries and exits.
-
 ## 2. Mathematical Foundations and Calculation Logic
 
 The CG Oscillator is a FIR (Finite Impulse Response) filter that calculates the position-weighted average of prices over a given period.
@@ -20,52 +23,74 @@ The CG Oscillator is a FIR (Finite Impulse Response) filter that calculates the
 ### Required Components
 
 * **Period (N):** The lookback period for the calculation.
-* **Source Price (P):** The price series used for the calculation (Ehlers' original work uses the Median Price `(H+L)/2`).
+* **Source Price (P):** The price series used for the calculation (Median Price `(H+L)/2`).
 
 ### Calculation Steps (Algorithm)
 
 For each bar, the indicator looks back over the last `N` periods.
 
 1. **Calculate Numerator:** Sum the prices, with each price multiplied by its position in the window. The most recent price gets a weight of 1, the next a weight of 2, and so on.
-    $\text{Numerator} = \sum_{i=0}^{N-1} (i+1) \times P_{i}$
+    $$ \text{Numerator} = \sum_{i=0}^{N-1} (i+1) \times P_{i} $$
 2. **Calculate Denominator:** Sum the prices over the window without any weighting.
-    $\text{Denominator} = \sum_{i=0}^{N-1} P_{i}$
-3. **Calculate Final CG Value:** The final value is the negative ratio of the two sums. The negative sign is used to bring the oscillator in phase with the price.
-    $\text{CG} = - \frac{\text{Numerator}}{\text{Denominator}}$
-4. **Signal Line Generation:** The Signal Line is simply the CG line's value from one bar prior.
+    $$ \text{Denominator} = \sum_{i=0}^{N-1} P_{i} $$
+3. **Calculate Raw CG Value:** The raw value is the negative ratio of the two sums.
+    $$ \text{CG}_{\text{raw}} = - \frac{\text{Numerator}}{\text{Denominator}} $$
+
+### Mode Differences
+
+* **Original Mode:** Returns $\text{CG}_{\text{raw}}$. The values will be negative and centered around $-(N+1)/2$.
+* **Pro Mode:** Adds an offset to center the oscillator around zero.
+    $$ \text{CG}_{\text{pro}} = \text{CG}_{\text{raw}} + \frac{N+1}{2} $$
 
 ## 3. MQL5 Implementation Details
 
 * **Self-Contained Calculator (`CG_Oscillator_Calculator.mqh`):** The entire calculation is encapsulated within a dedicated, reusable calculator class.
 * **Heikin Ashi Integration:** An inherited `_HA` class allows the calculation to be performed seamlessly on the Median Price of smoothed Heikin Ashi data.
-* **FIR-based Logic:** The CG Oscillator is a non-recursive (FIR) filter. Its calculation at any given bar depends only on the last `N` prices, giving it a finite "memory."
-* **Stability via Full Recalculation:** The indicator employs a full recalculation on every `OnCalculate` call to ensure stability and accuracy.
+* **Incremental Optimization:** The indicator uses `prev_calculated` to optimize performance, recalculating only new bars while maintaining mathematical precision.
 
 ## 4. Parameters
 
 * **Period (`InpPeriod`):** The lookback period (`N`) for the center of gravity calculation. Ehlers' recommendation is to set this to **half the length of the dominant market cycle**. A good starting point for most intraday charts is **10**.
-  * A shorter period makes the indicator faster and more responsive to small swings.
-  * A longer period makes the indicator smoother and responsive only to larger swings.
-* **Source (`InpSource`):** Selects between `Standard` and `Heikin Ashi` candles. The Median Price of the selected candle type will be used.
+* **Source (`InpSource`):** Selects between `Standard` and `Heikin Ashi` candles.
+* **Original Mode (`InpOriginalMode`):**
+  * `true`: Uses the strict Ehlers formula (Negative values).
+  * `false`: Centers the oscillator around 0.0 for better readability.
 
 ## 5. Usage and Interpretation
 
 The CG Oscillator is a **timing indicator for cycle reversals**. Its primary signal is the crossover of its two lines.
 
-**Important Note:** Unlike many other oscillators, the CG Oscillator **does not have a fixed horizontal axis or a meaningful zero line**. Its values "float" depending on the absolute price level of the instrument. Therefore, strategies based on zero-line crosses or fixed overbought/oversold levels are not applicable here.
-
 ### **1. Signal Line Crossover (Primary Strategy)**
 
 This is the most direct and Ehlers-recommended way to use the indicator.
 
-* **Buy Signal:** The **red CG line crosses above the blue Signal line**. This indicates that the market's "balance point" is shifting towards more recent, rising prices, signaling the start of an upswing.
-* **Sell Signal:** The **red CG line crosses below the blue Signal line**. This indicates the balance point is shifting towards falling prices, signaling the start of a downswing.
+* **Buy Signal:** The **red CG line crosses above the blue Signal line**. This indicates that the market's "balance point" is shifting towards more recent, rising prices.
+* **Sell Signal:** The **red CG line crosses below the blue Signal line**. This indicates the balance point is shifting towards falling prices.
 
-### **2. Use with a Trend Filter (Highly Recommended)**
+### **2. Center Line Reference (Original Mode vs. Pro Mode)**
+
+Understanding where the "neutral" state lies is crucial for assessing whether the market is extended.
+
+**Pro Mode:**
+The neutral line is always **0.0**. Values above 0 suggest bullish momentum; values below 0 suggest bearish momentum.
+
+**Original Mode:**
+The neutral line "floats" depending on the **Period** selected. It is calculated as $-(Period + 1) / 2$. If you use Original Mode, you may want to manually draw a horizontal line at the following levels to visualize the center:
+
+| Period (N) | Recommended Center Line Level |
+| :---: | :---: |
+| **8** | **-4.5** |
+| **9** | **-5.0** |
+| **10** | **-5.5** |
+| **11** | **-6.0** |
+| **12** | **-6.5** |
+| **13** | **-7.0** |
+
+    Formula: Center = -(Period + 1) / 2
+
+### **3. Use with a Trend Filter (Highly Recommended)**
 
 Due to its high responsiveness and "zero-lag" nature, the CG Oscillator can produce many signals in a choppy market. It is most effective when its signals are filtered by the primary trend.
 
-* **Uptrend Rule:** In a clear uptrend (e.g., price is above a 200-period EMA or a long-period SuperSmoother), only take **Buy signals** from the CG Oscillator. These signals can be used to time entries at the end of pullbacks.
-* **Downtrend Rule:** In a clear downtrend, only take **Sell signals**. These signals can be used to time short entries at the end of corrective rallies.
-
-By combining the CG Oscillator's precise timing with a robust trend filter, traders can create a powerful system for entering trades in the direction of the main market momentum.
+* **Uptrend Rule:** In a clear uptrend, only take **Buy signals** (Red crosses above Blue).
+* **Downtrend Rule:** In a clear downtrend, only take **Sell signals** (Red crosses below Blue).