Binned fill/colour scale with explicit class breaks (R’s
scale_fill_steps/scale_fill_fermenter generalised to arbitrary,
caller-supplied edges — ggplot2’s scale_fill_binned with breaks set
“manually”), backing a ::CLASSES choropleth (sipemu/ggplot-rs#180).
Bivariate fill scale: two binned variables → an n × m palette
(biscale-style; Stevens 1994’s bivariate-choropleth method), backing a
::BIVARIATE choropleth. Ported from the design in
anofox-visualization’s docs/plans/plan-maps.md (§15, D10) — DataZooDE/
anofox-visualization#318, #182.
A color scale that wraps another scale and adjusts the lightness of its
mapped colors — the backing implementation for after_scale color
derivations (e.g. a fill that is a darker version of the mapped color).
ggplot2’s “out of bounds” handling for a continuous colour scale’s fixed
with_limits domain — e.g.
fixing [-1, 1] for a correlation matrix so the colours (not just the
legend) reflect that fixed range rather than whatever the data happens
to span.