ConformalLabpp

conformallab/ConformalLabpp

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Author	SHA1	Message	Date
Tarik Moussa	02a3745b67	examples: add real conformal-flattening + CGAL-API examples (U1+U2) Finding-U1 and Finding-U2 from doc/reviewer/usability-audit-2026-05-31.md. The existing examples (example_euclidean, example_layout, example_hyper_ideal) all used the "natural theta" pattern which makes x*=0 trivially the equilibrium — u_v ≈ 0 everywhere, no deformation. A new user following these examples saw solver output but not conformal geometry. New: example_flatten.cpp - PRIMARY USE CASE: conformally flatten a mesh to the plane - Sets Θ_v = 2π for all interior vertices (flat target) - Pins boundary vertices (no Gauss-Bonnet check for open meshes) - Demonstrates non-trivial u_v (cathead.obj: range ≈ 2.96, 5 Newton iters) - Documents the difference from "natural theta" explicitly New: example_cgal_api.cpp - Demonstrates CGAL::discrete_conformal_map_euclidean (Discrete_conformal_map.h) - First runnable CGAL public API example; contrast with internal API - Documents the "natural theta" default behaviour and explains why u_v=0 - Explains when to use CGAL API vs internal API Both examples registered in code/examples/CMakeLists.txt and compile cleanly with -DWITH_CGAL=ON. Updated: - example_euclidean.cpp: prominent "TESTING CONVENTION" warning - example_layout.cpp: same warning on set_natural_theta helper - doc/getting-started.md: example_flatten is now the recommended "start here" example; note on natural-theta behaviour added Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>	2026-05-31 01:35:37 +02:00
Tarik Moussa	b7593e3f6d	feat(phase5): Layout, CLI, JSON/XML serialisation — 95 tests Phase 5 complete: layout.hpp - euclidean_layout(): BFS unfolding in ℝ² using trilaterate_2d - spherical_layout(): BFS on S² using trilaterate_sph (spherical law of cosines) - hyper_ideal_layout(): BFS in Poincaré disk (tanh(d/2) Euclidean approx) - save_layout_off(): convenience OFF writer for 2-D and 3-D layouts serialization.hpp - save/load_result_json(): nlohmann/json; stores DOF vector + uv/pos layout - save/load_result_xml(): hand-written writer/parser; same schema conformallab_cli.cpp (rewritten) - CLI11 interface: -i/-o/-g/-j/-x/-s/-v - Dispatches to euclidean / spherical / hyper_ideal pipeline - Runs Newton, computes layout, saves OFF + JSON + XML examples/example_layout.cpp - Full round-trip demo: solve → layout → JSON/XML → reload → verify tests/cgal/test_layout.cpp (8 tests) - Euclidean_PreservesEdgeLengths, CorrectVertexCount, TriangleIsNonDegenerate - Spherical_PreservesArcLengths, PositionsOnUnitSphere - HyperIdeal_SuccessAndFinitePositions - Serialization.JSON_RoundTrip, XML_RoundTrip All 95 CGAL tests pass (2 skipped — Hessian stubs unchanged). Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>	2026-05-13 00:53:47 +02:00

Author

SHA1

Message

Date

Tarik Moussa

02a3745b67

examples: add real conformal-flattening + CGAL-API examples (U1+U2)

Finding-U1 and Finding-U2 from doc/reviewer/usability-audit-2026-05-31.md.

The existing examples (example_euclidean, example_layout, example_hyper_ideal)
all used the "natural theta" pattern which makes x*=0 trivially the
equilibrium — u_v ≈ 0 everywhere, no deformation. A new user following
these examples saw solver output but not conformal geometry.

New: example_flatten.cpp
  - PRIMARY USE CASE: conformally flatten a mesh to the plane
  - Sets Θ_v = 2π for all interior vertices (flat target)
  - Pins boundary vertices (no Gauss-Bonnet check for open meshes)
  - Demonstrates non-trivial u_v (cathead.obj: range ≈ 2.96, 5 Newton iters)
  - Documents the difference from "natural theta" explicitly

New: example_cgal_api.cpp
  - Demonstrates CGAL::discrete_conformal_map_euclidean (Discrete_conformal_map.h)
  - First runnable CGAL public API example; contrast with internal API
  - Documents the "natural theta" default behaviour and explains why u_v=0
  - Explains when to use CGAL API vs internal API

Both examples registered in code/examples/CMakeLists.txt and compile
cleanly with -DWITH_CGAL=ON.

Updated:
  - example_euclidean.cpp: prominent "TESTING CONVENTION" warning
  - example_layout.cpp: same warning on set_natural_theta helper
  - doc/getting-started.md: example_flatten is now the recommended
    "start here" example; note on natural-theta behaviour added

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

2026-05-31 01:35:37 +02:00

Tarik Moussa

b7593e3f6d

feat(phase5): Layout, CLI, JSON/XML serialisation — 95 tests

Phase 5 complete:

layout.hpp
  - euclidean_layout(): BFS unfolding in ℝ² using trilaterate_2d
  - spherical_layout(): BFS on S² using trilaterate_sph (spherical law of cosines)
  - hyper_ideal_layout(): BFS in Poincaré disk (tanh(d/2) Euclidean approx)
  - save_layout_off(): convenience OFF writer for 2-D and 3-D layouts

serialization.hpp
  - save/load_result_json(): nlohmann/json; stores DOF vector + uv/pos layout
  - save/load_result_xml(): hand-written writer/parser; same schema

conformallab_cli.cpp (rewritten)
  - CLI11 interface: -i/-o/-g/-j/-x/-s/-v
  - Dispatches to euclidean / spherical / hyper_ideal pipeline
  - Runs Newton, computes layout, saves OFF + JSON + XML

examples/example_layout.cpp
  - Full round-trip demo: solve → layout → JSON/XML → reload → verify

tests/cgal/test_layout.cpp (8 tests)
  - Euclidean_PreservesEdgeLengths, CorrectVertexCount, TriangleIsNonDegenerate
  - Spherical_PreservesArcLengths, PositionsOnUnitSphere
  - HyperIdeal_SuccessAndFinitePositions
  - Serialization.JSON_RoundTrip, XML_RoundTrip

All 95 CGAL tests pass (2 skipped — Hessian stubs unchanged).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

2026-05-13 00:53:47 +02:00

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