Which matplotlib layout engine positions the mosaic’s axes. Unset lets the backend pick (bsplot asks for ‘compressed’ and falls back to ‘tight’), which is right for a plain grid of plots. A figure whose panels carry their own absolute geometry — a schematic stepped out in axes fractions, or a mosaic dense enough that the constrained solver reports cells collapsed to zero and silently falls back — has to say so, because an engine that gives up still leaves the figure laid out by a fallback nobody declared.
name: LayoutEnginedescription: Which matplotlib layout engine positions the mosaic's axes. Unset lets the backend pick (bsplot asks for 'compressed' and falls back to 'tight'), which is right for a plain grid of plots. A figure whose panels carry their own absolute geometry — a schematic stepped out in axes fractions, or a mosaic dense enough that the constrained solver reports cells collapsed to zero and silently falls back — has to say so, because an engine that gives up still leaves the figure laid out by a fallback nobody declared.from_schema: https://w3id.org/tvbo/figurepermissible_values:constrained:text: constraineddescription: Solve the margins so no decoration overlaps another panel. The general-purpose engine.compressed:text: compresseddescription: Constrained, then pull fixed-aspect axes together so equal-aspect panels leave no gap between them.tight:text: tightdescription: Adjust the subplot parameters after the fact to fit the decorations. No solver, so it cannot honour a shared aspect.none:text: nonedescription:'No engine: every axes keeps the position its gridspec cell gives it, and anything placed at absolute geometry survives the draw.'