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Fix SubFigure wspace/hspace None defaulting to subplot rc spacing#32080

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Fstarnb:fix/subfigures-none-spacing
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Fix SubFigure wspace/hspace None defaulting to subplot rc spacing#32080
Fstarnb wants to merge 1 commit into
matplotlib:mainfrom
Fstarnb:fix/subfigures-none-spacing

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@Fstarnb

@Fstarnb Fstarnb commented Jul 20, 2026

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Description

Without a layout engine, Figure.subfigures documents that unspecified wspace / hspace is zero. GridSpec still substitutes figure.subplot.{w,h}space rc defaults (typically 0.2) when given None, so:

  • subfigures(..., wspace=0.2, hspace=None) incorrectly added a vertical gap
  • subfigures(..., wspace=None, hspace=0.2) incorrectly added a horizontal gap

This is a regression from #25960 (confirmed in #32076).

Fix: when no layout engine is active, coerce missing wspace/hspace to 0.0 before constructing the GridSpec.

Related Issue

Fixes #32076

How Has This Been Tested?

Local verification (Agg, matplotlib 3.10.x / main sources):

  1. Red on main: wspace=0.2, hspace=None → subfigure height ≈ 181.82 (gap from default hspace=0.2)
  2. Green with fix: same call → height = 200 (half of 400px figure, no vertical gap)
  3. Issue reproducer bounds match expected:
    • both None → tiled (0, 200, 300, 200) etc.
    • only wspace → horizontal spacing only
    • only hspace → vertical spacing only
  4. Existing test_subfigures_wspace_hspace still passes
  5. New test_subfigures_partial_spacing_none_is_zero covers the three cases above

Checklist

Without a layout engine, Figure.subfigures documents that unspecified
wspace/hspace is zero. GridSpec still substitutes figure.subplot.* rc
defaults (0.2) for None, so setting only wspace applied a vertical gap
from the default hspace (and vice versa). Coerce missing spacings to 0.0
when no layout engine is active. Fixes matplotlib#32076.
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@rcomer

rcomer commented Jul 22, 2026

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This PR shows indications of having been generated by AI. Please check it against our policy and, if it complies, update the PR summary to use our template.
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@rcomer rcomer added the status: autoclose candidate PRs that are not yet ready for review and may be automatically closed in two weeks label Jul 22, 2026
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SubFigure hspace=None incorrectly applies default vertical spacing when wspace is specified

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