Background color

Kind: module

Namespace: bgColor

Paints a per-bar background color on the chart. For line or histogram series, use spline; for numeric outputs without drawing, use output.

Each bgColor layer maintains one color per bar. A new color is added when a new bar starts and replaced when the current bar updates.

bgColor()

Kind: func

Outputs a background color for the current bar for one layer.

Syntax

bgColor(color) → void
bgColor(color, {title, offset, numberOfLast, overlay}) → void

Arguments

Name	Type	Description
color	color?	Color for the current bar. Pass null if this layer should not paint on this bar.

Options

Static (ignored after the first call):

Name	Type	Default	Description
title?	string	null	Display name in the legend
offset?	int	0	Horizontal offset in bars (positive = right)
numberOfLast?	int	0	How many of the last bars this layer applies to (host-defined semantics)
overlay?	boolean	true	If true, draws on the main price chart instead of a separate pane (same idea as spline)

The color is always the first argument (not an option), so it can change on every tick.

Returns

void

Caveats

• Must be called inside onTick(), not in the init section
• Must be at the top level of onTick(), not inside conditionals or loops. This ensures the call count and order remain constant across ticks

Pitfall

function onTick() {
    if (bar.isConfirmed()) {
        bgColor(color.RED);  // ❌ inside conditional
    }
}

Example

const bull = input.color("Bull", color.GREEN);
const bear = input.color("Bear", color.RED);

function onTick() {
    const regime = close > ta.sma(close, 20);

    bgColor(regime ? bull : bear, {
        title: "Regime",
        offset: 0,
        numberOfLast: 100,
        overlay: true
    });
}