Fixture-symbol regression baseline

Structural baseline

The baseline in tests/fixtures/fixture_symbols/ freezes the current top, bottom, front, and left-side symbol structure. Each text file records the view identity, calibrated bounds and dimensions, calibration offsets (the bounds minimum), stroke width, ordered fill polygons and holes, ordered strokes, and the complete serialized SVG including its viewBox and translated coordinates.

The test constructs a 14 by 12 RGBA image directly in memory. A blue, asymmetric stepped silhouette, an off-centre cut-out, and a black line vary by view, making rotation and reflection mistakes visible without loading an image file. It then calls the production Symbol2DImageBuilder, geometry simplifier, GUI-independent physical calibration core, and ExportSymbolToSvgString. Consequently the test needs no OpenGL driver, GPU, font renderer, image decoder, or filesystem timestamps.

Snapshot structure uses deterministic production ordering. The review layer uses the classic C locale and rounds structural floating-point values to four decimal places (a tolerance of 0.00005 physical units); complete production SVG text is also retained. An intentional update must be made by reviewing and editing the four checked-in text files in the same change as the production change. The test has no golden-file update mode. Reviewers should compare view orientation, bounds and offsets, point order and counts, and SVG coordinates, not merely a digest.

Production contour extraction stores directed boundary edges in a sorted vector and indexes outgoing edges with an ordered map. Traversal starts from the first unconsumed edge and prefers the turn that keeps filled pixels on the right, followed by straight, left, and reverse continuations with the destination as an explicit tie-breaker. Implicitly closed rings preserve winding and rotate to the lexicographically smallest (x, y) vertex. Outer polygons sort by descending absolute area and then their full canonical sequence; holes sort by their full canonical sequence without changing ownership.

Closed-ring simplification uses the canonical first vertex and its deterministically selected farthest vertex as anchors. The two forward ring chains between those anchors are simplified independently with the existing RDP epsilon and merged without duplicate anchors. This makes simplification invariant under cyclic input rotation without treating open strokes as rings. The four baselines were updated for canonical point rotations and the reviewed deterministic removal or retention of seam-adjacent vertices. Their bounds, dimensions, offsets, polygon/hole topology, stroke width, and SVG view boxes are unchanged; contour tests additionally verify exact extracted filled area.

This is a structural rather than pixel baseline because GPU rasterization and driver behaviour are not portable across Linux, Windows, and macOS. It freezes the deterministic pipeline after capture while leaving optional real-renderer tests free to provide additional integration coverage.

Capture-view contract

Runtime capture consumes FixtureSymbolCapturePlan(), which has this stable order:

1. Front viewer view to front symbol, without horizontal mirroring.
2. Top viewer view to top symbol, without horizontal mirroring.
3. Side viewer view to left/side symbol, with horizontal mirroring.
4. Top viewer view with the bottom override to bottom symbol, without horizontal mirroring.

Timing diagnostics

FixtureSymbolTimings is an optional, independently owned model based on std::chrono::steady_clock. Disabled collection does not read the clock inside phase scopes. The formatting contract produces one compact fixture work record with the following stable phase order. Collection is optional; disabled sinks do not read clocks inside phase scopes or submit a timing record. The helper does not own preparation, project persistence, or GDTF completion policy.

• resolve: deterministic GDTF path resolution.
• fingerprint: source-content hashing and cache validation-request assembly.
• inspect: inspection of the existing archive and symbol set.
• bounds: fixture geometry-bound resolution before viewport sizing.
• capture: the four existing GUI-thread RenderToRGBA calls, including each view setup and required side mirror.
• vectorization: Symbol2DImageBuilder conversion and existing geometry simplification.
• calibration: physical-unit calibration after capture.
• archive_rewrite: the retained diagnostic field for intentional standard GDTF resource mutation and canonical atomic publication. Project-symbol Apply stores PSTG data independently and never rewrites GDTF.
• validation: exact stored-view inspection before a runtime skip, plus post-replacement entry and semantic-fingerprint validation. Repeated scopes accumulate for generated work.
• refresh: the existing scene refresh after a successful apply.

An absent phase is formatted as -; the programmatic accessor returns zero for that phase. Repeated phase scopes accumulate. total_us is wall-clock elapsed time for the fixture work record and can therefore exceed the phase sum.

A stored-SVG-valid skipped job contains resolve and exact-view validation; an inspection skip also contains inspect. A generated job contains all applicable phases, including bounds through refresh and any separately requested publication phases. A failed job keeps every phase completed before its failure; later phases remain absent. Outcomes are deliberately limited to skipped, generated, and failed by the current contract.

Model ownership and project preparation

GdtfModelSvgInspection exercises Base/Yoke/Head/Pixel resources, shared Pixel Geometry references, exact paths/offsets, absent File and duplicated File. SymbolFixtureApplierGdtf requires PSTG-only capture under both historical policies, byte-identical source and unchanged references in saved/unsaved scenes; its existing project Save/Load, override, Undo/Redo and legacy checks remain. GdtfResourceSvgBitmap also exercises Fixture Editor Model selection, unchanged project previews and canonical SVG-only/PNG-only thumbnails. Resource existence is tested independently of internal polygon parsing. GdtfGeometryInspection checks All/Solo filtering of repeated Models without changing tree transforms. The model SVG boundary guard forbids automatic capture/publication coupling. Native platform layout, OpenGL navigation and CJK font validation remain manual release checks in addition to the automated Linux GUI tests.