vellumplot 0.2.0

vellumplot 0.2.0

Grammar-breadth release: new scales, mapped aesthetics, legend control, and
distribution marks, closing the most conspicuous gaps versus ggplot2.

Scales & axes

• Date/time scales: scale_x_date() / scale_x_datetime() /
  scale_x_time() (and y twins) with date_breaks (interval strings like
  "3 months") and date_labels (strftime formats). Date/POSIXct columns
  still get a sensible date axis automatically.
• New mapped aesthetics: scale_alpha() (continuous opacity) and
  scale_linetype() (discrete line types), each drawn per element with its own
  legend. alpha mapped to data now varies opacity (previously constant-only);
  linetype applies to mark_line() / mark_step().
• Identity scales: scale_color_identity(), scale_fill_identity(),
  scale_size_identity(), scale_shape_identity(), scale_alpha_identity(),
  scale_linetype_identity() — use data values verbatim, no legend.
• Limit shortcuts: xlim(), ylim(), and lims().
• Legend control: guides() with guide = "none" (hide a legend),
  guide_legend(reverse = TRUE) (reverse key order), and guide_legend(title=).

Marks & stats

• Distribution marks: mark_ecdf() (empirical CDF step), mark_rug()
  (marginal ticks), mark_qq() + mark_qq_line() (quantile-quantile plot).
• Density-shape marks: mark_violin() (mirrored density per category),
  mark_ridgeline() (overlapping per-category densities), and mark_dotplot()
  (binned, stacked dots). Violin and ridgeline carry per-category provenance.

Not yet implemented (still planned)

Secondary axes (sec_axis/dup_axis); 2-D density / contour
(mark_contour/stat_density_2d); position-binned scales (scale_x_binned);
coord_trans() and free non-position scales across facets; triple-merge legends
(colour+shape+size) and NA keys for size/shape.