arcLine

Draws a curved arc using three anchors. Great for highlighting rounded moves, curved support/resistance, or rhythm in price swings. You can softly fill the area under the arc and keep the line clean and readable.

Syntax (one line)

arcLine(point1, point2, point3, styles?)

Parameters

point1 (PricedData) · First anchor (time & price) to start the arc. point2 (PricedData) · Middle control point that shapes the curve. point3 (PricedData) · Final anchor where the arc ends. styles (ArcLineToolOverrides) · Visual options for the arc and optional fill:

• backgroundColor (RGBAColor | BaseColors) · Fill color under the arc.

• color (RGBAColor | BaseColors) · Arc line color.

• fillBackground (boolean) · Turn the area fill on/off.

• linewidth (number) · Arc line thickness.

• transparency (number) · 0–100 fill transparency (higher = lighter).

Return Value

(string) · The drawing ID of the created Arc Line.

Example

What this does: Every 45 candles, it draws a blue arc from an older low to a later high, using a midpoint to shape the curve. We keep all visuals in one const style.

//@version=1
init = () => {
  indicator({ onMainPanel: true, format: 'inherit' });
};

onTick = () => {
  if (index % 45 === 0) { // draw occasionally to keep charts clean
    // 1) Choose three anchors to form the arc
    const p1 = newPoint(time(80), low(80));                 // start
    const p2 = newPoint(time(55), (high(55)+low(55))/2);    // bend the curve
    const p3 = newPoint(time(30), high(30));                // end

    // 2) Style (ArcLineToolOverrides)
    const style = {
      color: color.blue,
      linewidth: 2,
      fillBackground: true,
      backgroundColor: color.rgba(0, 102, 255, 0.2),
      transparency: 80
    };

    // 3) Draw the arc
    arcLine(p1, p2, p3, style);
  }
};

Tips

• Use a meaningful midpoint (point2) to control how much the arc bows; closer to point1 or point3 makes it tighter.

• Keep fills subtle so candles remain visible (raise transparency if it feels heavy).

Warning

• Very short spans can look like a straight line; space anchors enough to show a clear curve.

Good Practice

• Reuse a small set of arc colors (e.g., blue for bullish curves, red for bearish) for instant recognition.

• Pair arcs with ellipse or sineLine to study cyclical behavior.