Extracts MAIDR data plus the layer→dataset routing map from a Chart.js
chart instance.
Charts using Chart.js axis stacking (2+ scales of the same axis kind laid
out in separate bands via the scale stack option) become multi-subplot
figures: one MAIDR subplot per stacked panel, arranged as N rows × 1 column
for y-stacks (rows bottom-first, matching the grammar's matplotlib row
convention so Up/Down arrows track the on-canvas direction) and 1 row × N
columns for x-stacks (left-to-right). All other charts — including classic
dual-axis overlays — remain a single subplot.
Extracts MAIDR data plus the layer→dataset routing map from a Chart.js chart instance.
Charts using Chart.js axis stacking (2+ scales of the same axis kind laid out in separate bands via the scale
stackoption) become multi-subplot figures: one MAIDR subplot per stacked panel, arranged as N rows × 1 column for y-stacks (rows bottom-first, matching the grammar's matplotlib row convention so Up/Down arrows track the on-canvas direction) and 1 row × N columns for x-stacks (left-to-right). All other charts — including classic dual-axis overlays — remain a single subplot.