The Relative Strength Index oscillator displayed as a color histogram, using volumes.
Calculation formula:
RSI Histogram Vol = ( RSI - 50) * Volume
For quite understandable reasons, the recalculation of overbought and oversold levels in such a modified oscillator should be performed using the same formula. In the final version, these levels are no longer permanent. Two levels with the appropriate breakout indication were used.
input int                HighLevel2=+20;          // Overbought level 2 input int                HighLevel1=+15;          // Overbought level 1 input int                LowLevel1=-15;            // Oversold level 1 input int                LowLevel2=-20;            // Oversold level 2
In the indicator input parameters, these levels are shifted by the levels of 50 of the source RSI, and then multiplied by volumes at each indicator tick.
Fig. 1. The RSI_Histogram_Vol indicator