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Author SHA1 Message Date
Tarik Moussa
b7e837815f Phase 8b-Lite extension: output_uv_map named parameter for integrated layout
Closes the UX gap identified in the Phase-8b-Lite design discussion:
the four classical-DCE CGAL entries now optionally run their `*_layout()`
step internally if the caller supplies `CGAL::parameters::output_uv_map(pmap)`.

Before this PR, the workflow was:

    auto res = CGAL::discrete_conformal_map_euclidean(mesh);
    // ... user has to re-set up maps, re-pin vertex, then ...
    auto layout = euclidean_layout(mesh, res.x, maps);
    // ... and copy coordinates into a property map manually.

After this PR:

    auto uv = mesh.add_property_map<Vertex_index, K::Point_2>("uv", ...).first;
    CGAL::discrete_conformal_map_euclidean(
        mesh, CGAL::parameters::output_uv_map(uv));
    // ... uv now populated for every vertex.

Coverage
────────
* `discrete_conformal_map_euclidean`  — `Point_2` per vertex.
* `discrete_conformal_map_spherical`  — `Point_3` per vertex (on S²).
* `discrete_conformal_map_hyper_ideal` — `Point_2` per vertex (Poincaré disk).

CP-Euclidean and Inversive-Distance entries do not yet support
`output_uv_map` — face-based packing has no per-vertex UV concept, and
inversive-distance needs a dedicated layout routine that uses Luo's
edge-length formula (planned follow-up).

New named parameters (`code/include/CGAL/Conformal_map/internal/parameters.h`)
─────────────────────────────────────────────────────────────────────────────
* `output_uv_map(pmap)` — write coordinates into pmap after layout.
* `normalise_layout(bool)` — apply post-layout canonical normalisation
  (PCA centroid for Euclidean, north-pole alignment for Spherical,
  Möbius centring for Hyper-ideal).

Both follow the existing Phase-8a-MVP named-parameter convention.
Chained syntax (`.output_uv_map(...).normalise_layout(true)`) is not
yet supported — pass them one at a time.

Tests (5 new in test_cgal_phase8b_lite.cpp)
───────────────────────────────────────────
* `OutputUvMap_Euclidean_PopulatesPmap`         — UVs are finite + non-trivial.
* `OutputUvMap_Spherical_PopulatesXyz`          — every output on unit S².
* `OutputUvMap_HyperIdeal_PointsInPoincareDisk` — |p|² ≤ 1 if converged.
* `OutputUvMap_Absent_DoesNotRunLayout`         — no parameter ⇒ no layout.
* `OutputUvMap_NormaliseLayout_TakesEffect`     — both raw + norm calls
  return finite UVs (named-parameter chaining limitation documented).

All five pass.  Full CGAL suite: 232/232, 0 skipped (was 227).

doc/api/tests.md
────────────────
Updated the per-suite table to list the 7 CGAL test suites that landed
in v0.9.0 (8a MVP + 9a + 9b + 8b-Lite) but had not yet been added to the
canonical table.  Total: 227 → 232.  This brings the doc back in sync
with `ctest` output and unblocks future `scripts/check-test-counts.sh`
runs.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-05-22 13:24:37 +02:00
Tarik Moussa
7d10500811 Phase 8b-Lite: CGAL entries for all 5 DCE models + layout wrapper
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Completes the CGAL public API surface so all five discrete-conformal
functionals are reachable from <CGAL/Discrete_*.h>, not only Euclidean.

CGAL test count: 219 → 227 (+8).  Zero skips.

New public headers
──────────────────
* CGAL/Discrete_conformal_map.h                    extended
    Adds discrete_conformal_map_spherical() and
         discrete_conformal_map_hyper_ideal()
    plus the Hyper_ideal_map_result<FT> struct that carries both
    vertex DOFs (b_v) and edge DOFs (a_e).

* CGAL/Discrete_circle_packing.h                   new (180 lines)
    Face-based BPS-2010 circle packing.  Provides
         Default_cp_euclidean_traits<Mesh, K>
         Circle_packing_result<FT>
         discrete_circle_packing_euclidean()

* CGAL/Discrete_inversive_distance.h               new (180 lines)
    Vertex-based Luo-2004 packing.  Provides
         Default_inversive_distance_traits<Mesh, K>
         discrete_inversive_distance_map()
    reusing the existing Conformal_map_result<FT> for the u-vector.

* CGAL/Conformal_layout.h                          new (110 lines)
    Thin re-export of euclidean_layout / spherical_layout /
    hyper_ideal_layout into the CGAL:: namespace.

Architecture choice
───────────────────
Per Phase 8b architecture audit: Strategy C (functional-specific
default traits, one entry per functional, no fat shared trait).
Documented in each header's docblock.  This avoids speculative design
of a unified trait that would need to fit all 5 DOF layouts (vertex,
vertex+edge, face).

Conformal_map_traits.h is kept as the Euclidean-specific trait it
already is; new functionals have their own Default_*_traits classes
right next to their entry functions.

Test count after this merge
───────────────────────────
CGAL suite: 219 → 227 (8 new in test_cgal_phase8b_lite.cpp covering
all four new entries + the Euclidean+layout round-trip).

After-the-merge user contract
─────────────────────────────
A user can now write any of these and get a valid Newton-converged result:

  #include <CGAL/Discrete_conformal_map.h>
  auto r = CGAL::discrete_conformal_map_euclidean(mesh);
  auto r = CGAL::discrete_conformal_map_spherical(mesh);
  auto r = CGAL::discrete_conformal_map_hyper_ideal(mesh);

  #include <CGAL/Discrete_circle_packing.h>
  auto r = CGAL::discrete_circle_packing_euclidean(mesh);

  #include <CGAL/Discrete_inversive_distance.h>
  auto r = CGAL::discrete_inversive_distance_map(mesh);

  #include <CGAL/Conformal_layout.h>
  auto layout = CGAL::euclidean_layout(mesh, r.x, maps);

Not in this PR (intentionally deferred)
───────────────────────────────────────
* 8a.2 — Generic FaceGraph specialisation (still Surface_mesh-only).
* 8c   — User_manual + PackageDescription.txt (CGAL-submission prep).
* 8d   — CGAL-format test directory  (CGAL-submission prep).
* 8e   — YAML pipeline + CLI flag    (orthogonal).
* Named-parameter chaining (`a.b().c()`) — current parameter helpers
  return Named_function_parameters without member-function chainers;
  pass parameters one at a time for now.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-05-21 21:24:26 +02:00