GoFish Graphics
Internals

polygon ​

Draws a closed polygon from explicit local-coordinate points. Useful for non-rectangular glyphs (trapezoids, arrows, custom shapes) that can't be expressed by the standard shape primitives.

python
from gofish import chart, polygon

chart([{}]).mark(
    polygon(
        points=[
            [0, 0],
            [60, 0],
            [50, 40],
            [10, 40],
        ],
        fill="steelblue",
    )
).render(w=100, h=60)

Signature ​

python
polygon(*, points=None, fill=None, stroke=None, strokeWidth=None, debug=None) -> Mark

Keyword-only (matches every existing call site, which already passes points=... by keyword).

Parameters ​

ParameterTypeDefaultDescription
pointslist[list[float]]—Vertices in local coordinates. GoFish is y-up: [0, 0] is the bottom-left
fillstr"black"Fill color
strokestrfillStroke color (defaults to fill)
strokeWidthint0Stroke width

Returns a Mark for use in .mark(). Call .name() on the result to make it referenceable via ref / selectAll or a constraint.

Coordinates ​

Points are interpreted in the local coordinate system of whatever places the polygon — typically a layer or a constraint. The polygon's bounding box is the axis-aligned extent of its points; the parent placement system translates the whole polygon to position it.

GoFish is y-up internally, so a trapezoid whose wide edge sits at the bottom and narrow edge at the top is written:

python
polygon(
    points=[
        [0, 0],            # bottom-left (the wider edge)
        [width, 0],        # bottom-right
        [width - 10, h],   # top-right  (inset)
        [10, h],           # top-left   (inset)
    ],
)

Examples ​

python
# Trapezoidal weight glyph (from the pulley diagram)
polygon(
    points=[
        [0, 0],
        [width, 0],
        [width - 10, height],
        [10, height],
    ],
    fill="#545454",
).name("body")

# Triangle with stroke
polygon(
    points=[
        [0, 0],
        [40, 0],
        [20, 30],
    ],
    fill="transparent",
    stroke="black",
    strokeWidth=2,
)

Notes ​

  • The polygon is always closed — the last point connects back to the first automatically.
  • Points are literals, not channel-bound. If you need a polygon whose shape depends on data, compose multiple polygons or use a derived mark (@mark).