Module values 

Manual and identity scales for the numeric aesthetics (#408): ggplot2’s scale_size_manual() / scale_alpha_manual() / scale_linewidth_manual() (ScaleValueManual) and scale_size_identity() / scale_alpha_identity() / scale_linewidth_identity() / scale_shape_identity() (ScaleValueIdentity).

Structs

ScaleValueBinned

A binned scale for a non-position aesthetic (#408): ggplot2’s scale_size_binned() / scale_alpha_binned() / scale_shape_binned() / scale_linetype_binned() / scale_linewidth_binned(). A continuous value is cut into round, right-closed bins between about n breaks; each bin gets one size / alpha / line width (spread over range; sizes by area) or one shape / linetype, and the legend shows one key per bin, labelled lo–hi.

ScaleValueIdentity

An identity scale: the data already holds the size / alpha / line width (numbers) or point shape (ggplot2 pch codes, or a shape name such as "triangle") to draw with, used as-is. No legend, as in ggplot2 (guide = "none").

ScaleValueManual

A discrete scale mapping named levels to user-chosen numbers — point sizes, alpha values or line widths, by aesthetic (Size, Alpha or Linewidth). Levels the data has beyond values cycle through them, as ScaleShapeManual does.