Where two wet watercolour washes overlap the pigments diffuse and the colours mix - the "wet-on-wet" bleed. This approximates it without polygon clipping: it samples points lying inside both polygons (the overlap region) and returns soft translucent specks tinted with the blended colour. The grob layer paints the specks at low alpha over the two washes, so the shared area reads as mingled pigment. Pure geometry + colour math; reproduces on every device.
wash_bleed(
ax,
ay,
bx,
by,
col_a,
col_b,
density = 0.5,
bleed = NULL,
seed = NULL
)A list(x, y, r, fill) of bleed specks (inch space), or NULL when
the polygons' bounding boxes - or the sampled overlap - do not meet.
Vertices (inch space) of the two wash polygons.
The two wash colours (any R colour spec).
Fraction in [0, 1]: speck density in the overlap. Default
0.5.
Speck radius scale in inches. NULL (default) scales to ~2.5% of
the overlap's bounding diagonal.
Integer seed.
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(),
spray_scatter(),
stroke_profile(),
stroke_ribbon(),
treemap_layout(),
watercolor_wash(),
watercolor_wash_multi()