Example Convex Components

The following program generates a Hilbert polygon P1 of order 5 (see also Generators for Geometric Objects) and computes the convex components of P1. Then it draws the polygon and the edges of the convex components. On the right there is a screenshot of the program. Clicking on the picture shows the window in original size.

#include <LEDA/core/list.h>
#include <LEDA/geo/rat_point.h>
#include <LEDA/geo/rat_segment.h>
#include <LEDA/geo/rat_gen_polygon.h>
#include <LEDA/graphics/window.h>
#include <LEDA/geo/geo_alg.h>

using namespace leda;

int main()
{
  rational x1=10,y1=10,x2=100,y2=100;

  rat_polygon P1=hilbert(5,x1,y1,x2,y2);

  GRAPH<rat_point,rat_segment> G;
  list<edge> inner_edges, boundary_edges, hole_edges;
  edge edgeOnConvexHull
	  =CONVEX_COMPONENTS(P1,G,inner_edges,boundary_edges,hole_edges);

  window W;
  W.init(0,110,0);
  W.open(); W.display();
  W.set_node_width(2);

  W.draw_polygon(P1.to_polygon());
  W.read_mouse();
  
  edge e;
  forall_edges(e,G) {
    point p=G[G.source(e)].to_point();
    point q=G[G.target(e)].to_point();
    W.draw_segment(p,q,red);
  }
  W.read_mouse();

  W.screenshot("convex_components");

  return 0;
}	     

See also:

Convex Components

Data Types for 2-D Geometry

Generators for Geometric Objects

Windows and Panels

Linear Lists

Geometry Algorithms

Geometry

Graphs and Related Data Types

GeoWin

Number Types

Manual Entries

Manual Page of Geometry Algorithms