LineMark

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Connects data points with a continuous line, ideal for showing trends over time or continuous relationships between variables. Lines can be styled with different colors, widths, and interpolation methods. Optional symbols (markers) can be placed at each data point for individual value visibility.

LineMark is used inside a Chart container as one of the marks entries.

Constructor

nib.LineMark(
    x,
    y,
    foreground_style=None,
    symbol=None,
    interpolation=None,
    line_width=None,
    opacity=None,
)

Parameters

Parameter Type Default Description
x str \| PlottableField required Data field name for the x-axis position. Can be a string or a PlottableField with explicit type information.
y str \| PlottableField required Data field name for the y-axis position. Can be a string or a PlottableField with explicit type information.
foreground_style str \| PlottableField None Line color. Accepts hex strings ("#3B82F6"), named colors ("blue"), or a PlottableField to color lines by a data category (automatic palette assignment).
symbol SymbolShape \| str \| PlottableField None Shape of data point markers. Use a SymbolShape enum (CIRCLE, SQUARE, TRIANGLE, DIAMOND, CROSS, PLUS, PENTAGON, HEXAGON), a string, or a PlottableField to vary symbols by category.
interpolation InterpolationMethod \| str None Curve interpolation method between points. Options: LINEAR (default), MONOTONE, CATMULL_ROM, CARDINAL, STEP_START, STEP_CENTER, STEP_END.
line_width float None Width of the line in points. Uses system default when not specified.
opacity float None Opacity from 0.0 (transparent) to 1.0 (opaque).

Examples

Basic line chart

import nib

def main(app: nib.App):
    chart = nib.Chart(
        data=[
            {"month": "Jan", "temp": 5},
            {"month": "Feb", "temp": 7},
            {"month": "Mar", "temp": 12},
            {"month": "Apr", "temp": 17},
        ],
        marks=[nib.LineMark(x="month", y="temp")],
        width=300,
        height=200,
    )
    app.build(chart)

nib.run(main)

Styled line with symbols

import nib

chart = nib.Chart(
    data=monthly_data,
    marks=[
        nib.LineMark(
            x="month",
            y="sales",
            foreground_style="#3B82F6",
            symbol=nib.SymbolShape.CIRCLE,
            line_width=2.0,
            interpolation=nib.InterpolationMethod.MONOTONE,
        ),
    ],
    width=400,
    height=250,
)

Multi-series with color encoding

import nib

data = [
    {"date": "Jan", "value": 10, "series": "A"},
    {"date": "Feb", "value": 20, "series": "A"},
    {"date": "Jan", "value": 15, "series": "B"},
    {"date": "Feb", "value": 25, "series": "B"},
]

chart = nib.Chart(
    data=data,
    marks=[
        nib.LineMark(
            x="date",
            y="value",
            foreground_style=nib.PlottableField("series"),
        ),
    ],
    width=400,
    height=250,
)

Step chart for discrete events

import nib

chart = nib.Chart(
    data=state_changes,
    marks=[
        nib.LineMark(
            x="time",
            y="state",
            interpolation=nib.InterpolationMethod.STEP_END,
            foreground_style="#F59E0B",
        ),
    ],
    width=400,
    height=200,
)
Chart BarMark