Markers

The pydreamplet.markers module provides Marker, a reusable SVG <marker> wrapper, plus predefined path data constants for arrows, ticks, and simple symbols.

Markers are imported from pydreamplet.markers.

from pydreamplet.markers import ARROW_BASIC, Marker

Visual Example

Create markers inside Defs, then reference them from a line or path with marker_start, marker_mid, or marker_end.

import pydreamplet as dp
from pydreamplet.markers import ARROW_BASIC, DOT, Marker

svg = dp.SVG(300, 130)

defs = dp.Defs()
arrow = Marker("arrow-head", ARROW_BASIC, 10, 10, fill="#14b8a6", orient="auto")
dot = Marker("dot-start", DOT, 8, 8, fill="#f83898")
defs.append(arrow, dot)
svg.append(defs)

line = dp.Line(
    38,
    76,
    252,
    76,
    stroke="currentColor",
    stroke_width=3,
    stroke_linecap="round",
)
line.marker_start = dot.url
line.marker_end = arrow.url

svg.append(
    line,
    dp.Text("marker_start", x=38, y=48, font_size=12, text_anchor="middle", fill="currentColor"),
    dp.Text("marker_end", x=252, y=48, font_size=12, text_anchor="middle", fill="currentColor"),
    dp.Text("Marker(...).url", x=92, y=108, font_size=12, fill="currentColor"),
)

Marker

Marker(
    id: str,
    d: str,
    width: Real,
    height: Real,
    **kwargs: Any,
)

Marker creates a <marker> element with id, markerWidth, markerHeight, viewBox="0 0 10 10", refX, refY, and orient attributes. It also creates one nested Path whose d is the supplied marker shape.

Supported kwargs include:

refX, default "5"
refY, default "5"
orient, default "0"
fill, default "#000000" for the nested marker path
stroke, default "none" for the nested marker path
stroke-width, default "1" for the nested marker path

Because stroke-width is not a valid Python keyword, pass it with dictionary expansion when constructing a marker.

marker = Marker(
    "outlined-arrow",
    ARROW_BASIC,
    10,
    10,
    fill="none",
    stroke="currentColor",
    **{"stroke-width": "1.5"},
)

Properties

marker.d -> str
marker.d = ARROW_CONVEX

Gets or replaces the nested marker path data.

marker.fill -> str | None
marker.fill = "#14b8a6"

Gets or sets the nested path fill.

marker.stroke -> str | None
marker.stroke = "currentColor"

Gets or sets the nested path stroke.

marker.stroke_width -> Real | None
marker.stroke_width = "2"

Gets or sets the nested path stroke width. The getter returns the parsed numeric value from the underlying Path.

marker.url -> str

Returns url(#<id>), suitable for assigning to marker_start, marker_mid, or marker_end. The older id_ref property remains available as an alias.

marker = Marker("arrow", ARROW_BASIC, 10, 10)

assert marker.url == "url(#arrow)"

Predefined Paths

The module exports these path data constants:

Name	Shape
`ARROW`
`ARROW_BASIC`
`ARROW_CONCAVE`
`ARROW_CONVEX`
`ARROW_SIMPLE`
`CROSS`
`DIAMOND`
`DOT`
`SQUARE`
`TICK_BOTTOM`
`TICK_HORIZONTAL`
`TICK_LEFT`
`TICK_RIGHT`
`TICK_TOP`
`TICK_VERTICAL`

Use them as the d argument for Marker.

from pydreamplet.markers import ARROW_CONCAVE, Marker

marker = Marker("concave-arrow", ARROW_CONCAVE, 10, 10, fill="#14b8a6")

Marker is registered for the "marker" tag with SvgElement.register(), so marker elements found through SvgElement.find() are wrapped as Marker instances when possible.