# Thermodynamics verification

Validation against the final 1.7.0 checkout on 2026-09-30. CTAN submission and
publication status are recorded separately in `release-1.7.0.md`.

- All 15 regression suites pass. Generated reference and bundle freshness
  checks pass for 121 features.
- All 57 example documents compile (154 rendered pages) with the checkout
  forced through `TEXINPUTS`; each example has its own output directory.
- The isolated single-file runtime compiles eight module gallery documents
  and the six-page starter, using an empty user TeX tree. Recorders contain
  only the local bundled `tikzphysics.sty`, with no split physics libraries.
  Explicit meta/module/heattransfer alias requests also compile without
  loading system copies.
- All 17 module gallery pages are pixel-identical between split and isolated
  bundled runtimes at 72 dpi. Every sampled RGB pixel is monochrome.
- Every page of the thermodynamics, thermalphysics and elements galleries
  was visually inspected after the final runtime changes.
- Physical strokes inherit native TikZ line widths. A regression instrumenting
  actual PGF stroke calls verifies 1.25 pt document styling across mechanics,
  surfaces, ramps, optics, differential elements, fluids, thermodynamics and
  thermalphysics. No physical runtime imposes a custom stroke width; debug
  annotation leader lines retain their independent diagnostic styling.
- Overleaf archive integrity and the contents of all 20 files are checked.

Evidence: `tmp/release-1.7.0/` (compile recorders, raster comparisons, visual
renders, complete test output and independent loading probes).

The thermodynamics fixture contains 263 PASS records. It checks each integer
percentage, independent PV equations and Carnot state/branch coordinates,
compression, projections, hidden axes, circular ports, transformations,
instance isolation, pic flow directions and reference aliases. All 21
invalid-input cases reject before unsafe powers or invalid geometry.

The library provides 13 native nodes, two energy-flow pics and the heat-pump
pic alias. `thermodynamics.pdf` and `thermodynamics-scenes.pdf` contain six
visually reviewed pages. Fixed circular engine borders and diagonal anchors,
added shared PV frames, state projections, pic flow percentages and stable
large-parameter rejection. Axes and author-supplied labels remain adjustable.

PGF uses fixed precision and sampled curves. The library does not integrate
heat/work, compute entropy or solve real-gas equations.