This custom indicator provides a full implementation of the Average Directional Index (ADX) and Directional Indicators (DI) to measure trend strength and direction in financial markets. It displays four key lines: the ADX and ADI line (blue) representing smoothed trend strength regardless of direction; the +DI line (green) indicating upward movement strength; the -DI line (red) indicating downward movement strength; and a threshold line (gray, default 25) to identify significant trend strength.

The indicator calculates True Range (TR), Positive Directional Movement (+DM), and Negative Directional Movement (-DM), applying Wilder’s smoothing technique to derive smoothed values. From these, it computes the +DI and -DI lines to show bullish or bearish momentum. The Directional Index (DX) is calculated from the relative difference between +DI and -DI, and the ADX is a smoothed version of DX, quantifying overall trend strength.

Interpretation guidelines include: ADX above the threshold signals a strong trend; +DI greater than -DI indicates bullish control; -DI greater than +DI indicates bearish control; and ADX below the threshold suggests a ranging or weak trend market.