RSI Candles (RSI Chart Bar) - Technical Guide

Colors chart bars based on RSI: overbought above up_level, oversold below down_level, neutral otherwise.

Overview

RSI Chart Bars is an overlay indicator that colors each price bar according to the Relative Strength Index of that bar’s close. It uses a configurable RSI length (default 14) and two thresholds: up_level (default 70) and down_level (default 30). When RSI is above up_level, the bar is painted with up_color; when below down_level, it is painted with down_color; otherwise no color override is applied.

Because it works on the main chart pane (overlay_main_pane=True), it is meant for situations where an overbought/oversold RSI read should be visible without switching to a separate oscillator pane: trend exhaustion, pullback timing, and momentum filtering. The indicator does not draw lines, markers, or levels; its only output is the bar color returned through plot.BarColor.

How it works

1. An RSI series is created from the close series with Rsi.new(self.close, length).
2. The current bar’s RSI value is read with rsi[0].
3. If rsi_val > up_level, the bar color is set to up_color.
4. Otherwise, if rsi_val < down_level, the bar color is set to down_color.
5. If neither condition holds, None is returned as the color, leaving the default bar appearance.
6. The final plot.BarColor object tells the platform which color to paint the current bar.

Mathematical model

The code delegates RSI computation to the built-in Rsi algorithm. The conventional calculation represented by that algorithm is:

where U and D are the smoothed average gain and average loss over the configured length period.

Logic flow

flowchart TD
  A["Start bar"] --> B["Compute RSI from close with length"]
  B --> C{"RSI > up_level"}
  C -- "Yes" --> D["Return BarColor with up_color"]
  C -- "No" --> E{"RSI < down_level"}
  E -- "Yes" --> F["Return BarColor with down_color"]
  E -- "No" --> G["Return BarColor with None"]

Parameters

Code walkthrough

Indicator registration and settings

Lines 6-12 of RSI Candles (RSI Chart Bar).indie5:

@indicator('RSI Chart Bars', overlay_main_pane=True)
@param.int('length', default=14, min=1, title='Length')
@param.int('up_level', default=70, min=1, title='UpLevel')
@param.int('down_level', default=30, min=1, title='DownLevel')
@param.color('up_color', default=color.LIME, title='Overbought Color')
@param.color('down_color', default=color.FUCHSIA, title='Oversold Color')
@plot.bar_color(title='Bar Color')

@indicator places the script on the main chart rather than a separate pane. The @param.int and @param.color decorators define the UI settings for RSI length, thresholds, and bar colors. @plot.bar_color declares that the returned value is a bar color.

RSI calculation and current value

Lines 14-15 of RSI Candles (RSI Chart Bar).indie5:

    rsi = Rsi.new(self.close, length)
    rsi_val = rsi[0]

Rsi.new(self.close, length) returns an RSI series. Reading rsi[0] gets the value for the current bar, while rsi[1] would refer to the previous completed bar.

Color decision and return value

Lines 17-19 of RSI Candles (RSI Chart Bar).indie5:

    return plot.BarColor(
        up_color if rsi_val > up_level else down_color if rsi_val < down_level else None
    )

The nested conditional picks up_color for overbought RSI, down_color for oversold RSI, and None otherwise. Returning plot.BarColor with None means the chart uses the default bar style for that bar.

Reading the chart

• When a bar is painted with up_color (default lime), the current RSI is strictly above up_level, indicating an overbought condition.
• When a bar is painted with down_color (default fuchsia), the current RSI is strictly below down_level, indicating an oversold condition.
• Unpainted bars mean RSI is between down_level and up_level; the indicator does not draw anything else on the chart.
• The color is recalculated every bar from the current close, so the color on the active bar can change as price moves.

Implementation notes

• The comparison uses strict > and <; an RSI exactly equal to a threshold leaves the bar unpainted.
• rsi[0] is a same-bar value, so on the in-progress bar the color can change until the bar closes.
• The two thresholds are independent and do not need to be symmetric around 50.
• All RSI math is inside the built-in Rsi algorithm; this script only consumes its series.

FAQ

How do I change the overbought and oversold thresholds?

Change up_level and down_level in the indicator settings or in the @param.int defaults. They are independent, so you can use values such as 80 and 20.

Why are some bars unpainted when RSI is exactly 70 or 30?

The condition uses strict greater-than and less-than comparisons. If you want equality to count, edit lines 17-18 to use >= and <=.

Can I base the color on the previous bar instead of the current bar?

Yes, change rsi_val = rsi[0] to rsi_val = rsi[1] on line 15. This reads the previous completed bar’s RSI and makes the coloring one bar delayed.

Full source code

Indie Script v5, as published on TakeProfit. Copy it into the platform’s script editor or open the live script.

# indie:lang_version = 5
from indie import indicator, param, plot, color
from indie.algorithms import Rsi


@indicator('RSI Chart Bars', overlay_main_pane=True)
@param.int('length', default=14, min=1, title='Length')
@param.int('up_level', default=70, min=1, title='UpLevel')
@param.int('down_level', default=30, min=1, title='DownLevel')
@param.color('up_color', default=color.LIME, title='Overbought Color')
@param.color('down_color', default=color.FUCHSIA, title='Oversold Color')
@plot.bar_color(title='Bar Color')
def Main(self, length, up_level, down_level, up_color, down_color):
    rsi = Rsi.new(self.close, length)
    rsi_val = rsi[0]

    return plot.BarColor(
        up_color if rsi_val > up_level else down_color if rsi_val < down_level else None
    )