trendLine

Draw a simple line between two chart points to highlight a trend (for example, from a swing low to a swing high). You can also style the line and (optionally) show a small label on it. The function returns an id so you can update or delete the drawing later.

Syntax

trendLine(fromPoint, toPoint, styles?, text?)

Parameters

• fromPoint { time, price }: A point object with time and price, e.g. newPoint(time, price). This is where the line starts.

• toPoint { time, price }: A point object with time and price. This is where the line ends.

• styles (optional) Visual options for the line. Common fields you might use:

  • linecolor: line color (supports named colors like color.blue or RGBA via color.rgba(r,g,b,a))

  • linewidth: line thickness (number)

  • linestyle: line style (number; e.g., solid/dashed)

  • extendRight / extendLeft: keep the line extending beyond your points (boolean)

  • showLabel: show the text label if you pass text (boolean) (Full list available in BasicLineToolOverrides.)

• text string (optional): A short label that appears on the line (set styles.showLabel = true to display it).

Helper you’ll use

• newPoint(time, price) → returns a { time, price } point for drawing tools. Use it to build fromPoint and toPoint.

Return Value

• string — The unique drawing id. Save this if you plan to update or delete the line later with updateDrawingById(id, newData) or deleteDrawingById(id).

Example

Create a blue upward trend line from an older low to a newer high, extend it to the right, and add a label:

//@version=1
init = () => {
    // Overlay the indicator on the main price chart
    // "inherit" means it will use the same format as the chart
    indicator({ onMainPanel: true, format: 'inherit' });

    // Add an input so the user can define a volume threshold
    // Example: only draw the line if volume > threshold
    input.int("Volume Threshold", 20000, "volumeThreshold", 0, 100000, 100);
};

onTick = (length, _moment, _, ta, inputs) => {
    // Read the user’s input threshold
    const volumeThreshold = inputs.volumeThreshold;

    // Get current candle volume
    const vol = volume(0);

    // Check condition: only continue if volume is above the threshold
    if (vol > volumeThreshold) {
        // Define two points on the chart
        const p1 = newPoint(time(30), low(30));   // older swing low
        const p2 = newPoint(time(5), high(5));   // recent swing high

        // Draw a trendline between the two points
        trendLine(
            p1,
            p2,
            { linecolor: color.blue, linewidth: 2, extendRight: true, showLabel: true },
            'Uptrend (High Volume)'
        );
    }
};

Result

Tips

• Need a custom color? Use color.rgba(r, g, b, a) like color.rgba(0, 128, 255, 0.9) for semitransparent lines.

• Keep your labels short (a word or two) so they don’t clutter the chart.

• Save the returned id if you’ll move or remove the line later with updateDrawingById or deleteDrawingById.

Warning

• Your points must include both time and price. If they’re missing or invalid, the drawing won’t be created (the API validates points before drawing).

• If you pass text but forget showLabel: true in styles, the label won’t appear.

Good Practice

• Snap fromPoint/toPoint to meaningful pivots (e.g., recent swing high/low) for clearer trend visualization.

• Use extendRight: true to project the trend forward—great for seeing where price reacts next.

• Keep style settings consistent across your scripts (same linewidth, linestyle) so charts look clean and familiar.