cross_section.h

// Copyright 2023 The Manifold Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
 
#pragma once
 
#include <functional>
#include <memory>
#include <mutex>
#include <vector>
 
#include "manifold/common.h"
#include "manifold/vec_view.h"
 
namespace manifold {

 
struct PathImpl;

class CrossSection {
 public:
  CrossSection();
  ~CrossSection();
 
  CrossSection(const CrossSection& other);
  CrossSection& operator=(const CrossSection& other);
  CrossSection(CrossSection&&) noexcept;
  CrossSection& operator=(CrossSection&&) noexcept;
 
  // Adapted from Clipper2 docs:
  // http://www.angusj.com/clipper2/Docs/Units/Clipper/Types/FillRule.htm
  // (Copyright © 2010-2023 Angus Johnson)
  // TODO(#1707): EvenOdd/NonZero/Negative are preserved for backend/API
  // compatibility; remove them when the public construction API can break. The
  // Boolean2 backend supports only Positive construction.
  enum class FillRule {
    EvenOdd,   
    NonZero,   
    Positive,  
    Negative   
  };

  using JoinType = ::manifold::JoinType;

  CrossSection(const SimplePolygon& contour,
               FillRule fillrule = FillRule::Positive);
  CrossSection(const Polygons& contours,
               FillRule fillrule = FillRule::Positive);
  CrossSection(const Rect& rect);
  Polygons ToPolygons() const;

  std::vector<CrossSection> Decompose() const;
  static CrossSection Compose(const std::vector<CrossSection>&);
  static CrossSection Square(const vec2 dims, bool center = false);
  static CrossSection Circle(double radius, int circularSegments = 0);

  bool IsEmpty() const;
  size_t NumVert() const;
  size_t NumContour() const;
  Rect Bounds() const;
  double Area() const;

  CrossSection Translate(const vec2 v) const;
  CrossSection Rotate(double degrees) const;
  CrossSection Scale(const vec2 s) const;
  CrossSection Mirror(const vec2 ax) const;
  CrossSection Transform(const mat2x3& m) const;
  CrossSection Warp(std::function<void(vec2&)> warpFunc) const;
  CrossSection WarpBatch(std::function<void(VecView<vec2>)> warpFunc) const;
  CrossSection Simplify(double epsilon = 1e-6) const;
  CrossSection Offset(double delta, JoinType jt = JoinType::Round,
                      double miter_limit = 2.0, int circularSegments = 0) const;

  CrossSection Boolean(const CrossSection& second, OpType op) const;
  static CrossSection BatchBoolean(
      const std::vector<CrossSection>& crossSections, OpType op);
  CrossSection operator+(const CrossSection&) const;
  CrossSection& operator+=(const CrossSection&);
  CrossSection operator-(const CrossSection&) const;
  CrossSection& operator-=(const CrossSection&);
  CrossSection operator^(const CrossSection&) const;
  CrossSection& operator^=(const CrossSection&);

  CrossSection Hull() const;
  static CrossSection Hull(const std::vector<CrossSection>& crossSections);
  static CrossSection Hull(const SimplePolygon pts);
  static CrossSection Hull(const Polygons polys);
 
 private:
  mutable std::mutex pathsMutex_;
  mutable std::shared_ptr<const PathImpl> paths_;
  mutable mat2x3 transform_ = la::identity;
  // Propagated drift budget, analogous to Manifold::Impl::tolerance_.
  mutable double tolerance_ = 0.0;
  CrossSection(std::shared_ptr<const PathImpl> paths);
  std::shared_ptr<const PathImpl> GetPaths() const;
};

}  // namespace manifold