Samples points along a centreline and offsets each one perpendicular to the
path by a Gaussian random amount, producing a soft-edged spray of dots with no
hard outline – the airbrush / spray-can look. The dot density falls off from
the centreline (the Gaussian offset), and dots near the edge are drawn smaller
so the cloud feathers out. Pure number-to-number (no grid/ggplot2);
deterministic apart from the seeded RNG (ADR-0004).
Arguments
- x, y
Numeric vectors of centreline vertices (same length, any units –
spread,dot_randdensityare interpreted in those units).- spread
Standard deviation of the perpendicular offset (cloud half-width).
- density
Mean number of dots per unit of path arc-length.
- dot_r
Base dot radius. Edge dots shrink toward
0.4 * dot_r.- seed
Integer seed for the scatter (ADR-0004).
Value
A 4-column matrix with columns x, y (dot centres), r (dot radii)
and a (a 0-1 weight that fades with distance from the centreline, for the
caller to fold into per-dot alpha if desired). Zero rows for a degenerate
path.
See also
Other sketch-core:
arrowhead(),
curve_fill(),
engrave_fill(),
engrave_ladder(),
hachure_fill(),
hachure_fill_multi(),
leader_path(),
repel_layout(),
rough_arc(),
rough_bezier(),
rough_ellipse(),
roughen_polyline(),
sketch_arrowheads(),
sketch_fill(),
sketch_fill_multi(),
stroke_profile(),
stroke_ribbon(),
treemap_layout(),
wash_bleed(),
watercolor_wash(),
watercolor_wash_multi()