CGAL 6.2 - 2D Arrangements

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Arrangement_on_surface_2/draw_arr.cpp
#include <string>
#include <CGAL/Random.h>
#include <CGAL/Arr_linear_traits_2.h>
#include <CGAL/Exact_predicates_exact_constructions_kernel.h>
#include <CGAL/Arrangement_2.h>
#include <CGAL/Arr_segment_traits_2.h>
#include <CGAL/Arr_non_caching_segment_traits_2.h>
#include <CGAL/draw_arrangement_2.h>
std::tuple<unsigned char, unsigned char, unsigned char> hsv_to_rgb(float hue, float sat, float value) {
float red, green, blue;
float fc = value * sat; // Chroma
float hue_prime = fmod(hue / 60.0f, 6.f);
float fx = fc * (1.0f - fabs(fmod(hue_prime, 2.f) - 1.f));
float fm = value - fc;
if(0 <= hue_prime && hue_prime < 1) {
red = fc;
green = fx;
blue = 0;
}
else if(1 <= hue_prime && hue_prime < 2) {
red = fx;
green = fc;
blue = 0;
}
else if(2 <= hue_prime && hue_prime < 3) {
red = 0;
green = fc;
blue = fx;
}
else if(3 <= hue_prime && hue_prime < 4) {
red = 0;
green = fx;
blue = fc;
}
else if(4 <= hue_prime && hue_prime < 5) {
red = fx;
green = 0;
blue = fc;
}
else if(5 <= hue_prime && hue_prime < 6) {
red = fc;
green = 0;
blue = fx;
}
else {
red = 0;
green = 0;
blue = 0;
}
red += fm;
green += fm;
blue += fm;
red *= 255;
green *= 255;
blue *= 255;
unsigned char redc = (unsigned char)red;
unsigned char greenc = (unsigned char)green;
unsigned char bluec = (unsigned char)blue;
return std::make_tuple(redc, greenc, bluec);
}
void draw_rect() {
using Kernel = CGAL::Exact_predicates_exact_constructions_kernel;
using Traits = CGAL::Arr_non_caching_segment_traits_2<Kernel>;
using Point = Traits::Point_2;
using Arrangement = CGAL::Arrangement_2<Traits>;
Traits traits;
Arrangement arr(&traits);
auto ctr_xcv = traits.construct_x_monotone_curve_2_object();
CGAL::insert(arr, ctr_xcv(Point(-2, -2), Point(2, -2)));
CGAL::insert(arr, ctr_xcv(Point(2, -2), Point(2, 2)));
CGAL::insert(arr, ctr_xcv(Point(2, 2), Point(-2, 2)));
CGAL::insert(arr, ctr_xcv(Point(-2, 2), Point(-2, -2)));
CGAL::insert(arr, ctr_xcv(Point(-1, -1), Point(1, -1)));
CGAL::insert(arr, ctr_xcv(Point(1, -1), Point(1, 1)));
CGAL::insert(arr, ctr_xcv(Point(1, 1), Point(-1, 1)));
CGAL::insert(arr, ctr_xcv(Point(-1, 1), Point(-1, -1)));
CGAL::insert(arr, ctr_xcv(Point(-2, -2), Point(-2, -4)));
CGAL::insert(arr, ctr_xcv(Point(2, -2), Point(4, -2)));
CGAL::insert(arr, ctr_xcv(Point(0, 0), Point(0, -3)));
std::cout << arr.number_of_vertices() << ", " << arr.number_of_edges() << ", " << arr.number_of_faces() << std::endl;
CGAL::Graphics_scene_options<Arrangement, typename Arrangement::Vertex_const_handle,
typename Arrangement::Halfedge_const_handle, typename Arrangement::Face_const_handle>
gso;
gso.colored_face = [](const Arrangement&, Arrangement::Face_const_handle) -> bool { return true; };
gso.face_color = [](const Arrangement&, Arrangement::Face_const_handle fh) -> CGAL::IO::Color {
CGAL::Random random((size_t(fh.ptr())));
float h = 360.0f * random.get_double(0, 1);
float s = 0.5;
float v = 0.5;
auto [r, g, b] = hsv_to_rgb(h, s, v);
return CGAL::IO::Color(r, g, b);
};
CGAL::draw(arr, gso, "rect with hsv colors");
}
void draw_nested() {
using Kernel = CGAL::Exact_predicates_exact_constructions_kernel;
using Traits = CGAL::Arr_segment_traits_2<Kernel>;
using Point = Traits::Point_2;
using Arrangement = CGAL::Arrangement_2<Traits>;
using X_monotone_curve = Traits::X_monotone_curve_2;
Arrangement arr;
auto traits = arr.traits();
auto ctr_xcv = traits->construct_x_monotone_curve_2_object();
std::vector<X_monotone_curve> curves;
{
// a hexagon centered at the origin
const double r = 10.0;
for (int i = 0; i < 6; ++i) {
int next = (i + 1) % 6;
Point source(r * cos(i * CGAL_PI / 3), r * sin(i * CGAL_PI / 3));
Point target(r * cos(next * CGAL_PI / 3), r * sin(next * CGAL_PI / 3));
curves.push_back(ctr_xcv(source, target));
}
}
{
// a square inside the hexagon
const double size = 4.0;
Point p1(-size, size), p2(size, size), p3(size, -size), p4(-size, -size);
auto rect = {ctr_xcv(p1, p2), ctr_xcv(p2, p3), ctr_xcv(p3, p4), ctr_xcv(p4, p1)};
curves.insert(curves.end(), rect.begin(), rect.end());
}
{
// two adjacent triangle inside the square
Point p1(-1, 0), p2(1, 0), p3(0, sqrt(3)), p4(0, -sqrt(3));
auto tri1 = {ctr_xcv(p1, p2), ctr_xcv(p2, p3), ctr_xcv(p3, p1)};
auto tri2 = {ctr_xcv(p1, p2), ctr_xcv(p2, p4), ctr_xcv(p4, p1)};
curves.insert(curves.end(), tri1.begin(), tri1.end());
curves.insert(curves.end(), tri2.begin(), tri2.end());
}
// a degenerate hole inside the square
auto degen_seg = ctr_xcv({-1, -3}, {1, -3});
curves.push_back(degen_seg);
// an isolated vertex inside the square
auto iso_point = Point{1, -1};
CGAL::insert(arr, curves.begin(), curves.end());
CGAL::insert_point(arr, iso_point);
CGAL::draw(arr, "nested polygons");
}
void draw_unbounded_linear_grid() {
using Kernel = CGAL::Exact_predicates_exact_constructions_kernel;
using Traits = CGAL::Arr_linear_traits_2<Kernel>;
using Point = Traits::Point_2;
using Segment = Traits::Segment_2;
using Line = Traits::Line_2;
using X_monotone_curve = Traits::X_monotone_curve_2;
using Arrangement = CGAL::Arrangement_2<Traits>;
Arrangement arr;
// Insert a n*n grid
int n = 5;
for (int i = 0; i < n; ++i) {
Point p1(i * 5, 0);
Point p2(i * 5, 1);
CGAL::insert(arr, X_monotone_curve(Line(p1, p2)));
}
for (int i = 0; i < n; ++i) {
Point p1(0, i * 5);
Point p2(1, i * 5);
CGAL::insert(arr, X_monotone_curve(Line(p1, p2)));
}
// Generate a inner square(2*2) for all cells
// And an inner triangle for each square
for (int i = 0; i < n; ++i) {
for (int j = 0; j < n; ++j) {
Point p1(i * 5 + 1, j * 5 + 1);
Point p2(i * 5 + 4, j * 5 + 4);
CGAL::insert(arr, X_monotone_curve(Segment(p1, Point(p2.x(), p1.y()))));
CGAL::insert(arr, X_monotone_curve(Segment(Point(p1.x(), p2.y()), p2)));
CGAL::insert(arr, X_monotone_curve(Segment(p1, Point(p1.x(), p2.y()))));
CGAL::insert(arr, X_monotone_curve(Segment(Point(p2.x(), p1.y()), p2)));
// Insert a triangle inside the square
Point tri_p1(i * 5 + 2, j * 5 + 2);
Point tri_p2(i * 5 + 3, j * 5 + 2);
Point tri_p3(i * 5 + 2.5, j * 5 + 3);
CGAL::insert(arr, X_monotone_curve(Segment(tri_p1, tri_p2)));
CGAL::insert(arr, X_monotone_curve(Segment(tri_p2, tri_p3)));
CGAL::insert(arr, X_monotone_curve(Segment(tri_p3, tri_p1)));
// Connect the triangle to the square
Point top(i * 5 + 2.5, j * 5 + 4);
CGAL::insert(arr, X_monotone_curve(Segment(tri_p1, top)));
}
}
CGAL::draw(arr, "unbounded linear grid");
}
void draw_random_segments(int n) {
using Kernel = CGAL::Exact_predicates_exact_constructions_kernel;
using Traits = CGAL::Arr_segment_traits_2<Kernel>;
using Point = Traits::Point_2;
using Arrangement = CGAL::Arrangement_2<Traits>;
using X_monotone_curve = Traits::X_monotone_curve_2;
Arrangement arr;
auto traits = arr.traits();
auto ctr_xcv = traits->construct_x_monotone_curve_2_object();
CGAL::Random random;
std::vector<X_monotone_curve> curves;
for (int i = 0; i < n; ++i) {
double x1 = random.get_double(-100, 100);
double y1 = random.get_double(-100, 100);
double x2 = random.get_double(-100, 100);
double y2 = random.get_double(-100, 100);
curves.push_back(ctr_xcv(Point(x1, y1), Point(x2, y2)));
}
CGAL::insert(arr, curves.begin(), curves.end());
CGAL::draw(arr, (std::to_string(n) + " random segments").c_str());
}
int main() {
draw_rect();
draw_nested();
draw_unbounded_linear_grid();
draw_random_segments(100);
return EXIT_SUCCESS;
}
CGAL::Arr_linear_traits_2
The traits class Arr_linear_traits_2 is a model of the AosTraits_2 concept, which enables the constru...
Definition: Arr_linear_traits_2.h:27
CGAL::Arr_non_caching_segment_traits_2
The traits class Arr_non_caching_segment_traits_2 is a model of the AosTraits_2 concept that allows t...
Definition: Arr_non_caching_segment_traits_2.h:39
CGAL::Arr_segment_traits_2
The traits class Arr_segment_traits_2 is a model of the AosTraits_2 concept, which allows the constru...
Definition: Arr_segment_traits_2.h:58
CGAL::Arrangement_2
Definition: Arrangement_2.h:57
CGAL::Arrangement_2::traits
Traits * traits()
obtains the traits object used by the arrangement instance.
CGAL::Exact_predicates_exact_constructions_kernel
CGAL::IO::Color
CGAL::sqrt
NT sqrt(const NT &x)
CGAL::insert_point
Arrangement_2< Traits, Dcel >::Vertex_handle insert_point(Arrangement_2< Traits, Dcel > &arr, const typename Traits::Point_2 &p, const PointLocation &pl=walk_pl)
Inserts a given point into a given arrangement.
CGAL::insert
void insert(Arrangement_2< Traits, Dcel > &arr, const Curve &c, const PointLocation &pl=walk_pl)
The function insert inserts one or more curves or -monotone curves into a given arrangement,...
CGAL::draw
void draw(const PS2 &ps2, const GSOptions &gso)
Kernel