simple polygon in the plane represented by list of vertices More...
#include <visilibity.hpp>
Inheritance diagram for VisiLibity::Polygon:
Public Member Functions | |
| Polygon () | |
| default to empty | |
| Polygon (const std::string &filename) | |
| construct from *.polygon file More... | |
| Polygon (const std::vector< Point > &vertices_temp) | |
| construct from vector of vertices More... | |
| Polygon (const Point &point0, const Point &point1, const Point &point2) | |
| construct triangle from 3 Points More... | |
| const Point & | operator[] (unsigned i) const |
| access with automatic wrap-around in forward direction More... | |
| unsigned | n () const |
| vertex count More... | |
| unsigned | r () const |
| reflex vertex count (nonconvex vertices) More... | |
| bool | is_simple (double epsilon=0.0) const |
| true iff Polygon is (epsilon) simple More... | |
| bool | is_in_standard_form () const |
| true iff lexicographically smallest vertex is first in the list of vertices representing the Polygon More... | |
| double | boundary_length () const |
| perimeter length | |
| double | area () const |
| Point | centroid () const |
| Polygon's centroid (center of mass) More... | |
| double | diameter () const |
| Euclidean diameter. More... | |
| Bounding_Box | bbox () const |
| box which fits snugly around the Polygon More... | |
| std::vector< Point > | random_points (const unsigned &count, double epsilon=0.0) const |
| void | write_to_file (const std::string &filename, int fios_precision_temp=FIOS_PRECISION) |
| write list of vertices to *.polygon file More... | |
| Point & | operator[] (unsigned i) |
| access with automatic wrap-around in forward direction More... | |
| void | set_vertices (const std::vector< Point > &vertices_temp) |
| set vertices using STL vector of Points | |
| void | push_back (const Point &vertex_temp) |
| push a Point onto the back of the vertex list | |
| void | clear () |
| erase all vertices | |
| void | enforce_standard_form () |
| enforces that the lexicographically smallest vertex is first in the list of vertices representing the Polygon More... | |
| void | eliminate_redundant_vertices (double epsilon=0.0) |
| eliminates vertices which are (epsilon) - colinear with their respective neighbors More... | |
| void | reverse () |
| reverse (cyclic) order of vertices More... | |
Protected Attributes | |
| std::vector< Point > | vertices_ |
Friends | |
| class | Point |
Detailed Description
simple polygon in the plane represented by list of vertices
Simple here means non-self-intersecting. More precisely, edges should not (i) intersect with an edge not adjacent to it, nor (ii) intersect at more than one Point with an adjacent edge.
- Remarks
- vertices may be listed cw or ccw
Constructor & Destructor Documentation
◆ Polygon() [1/3]
| VisiLibity::Polygon::Polygon | ( | const std::string & | filename | ) |
construct from *.polygon file
- Remarks
- for efficiency, simplicity check not called here
◆ Polygon() [2/3]
| VisiLibity::Polygon::Polygon | ( | const std::vector< Point > & | vertices_temp | ) |
construct from vector of vertices
- Remarks
- for efficiency, simplicity check not called here
◆ Polygon() [3/3]
construct triangle from 3 Points
- Remarks
- for efficiency, simplicity check not called here
Member Function Documentation
◆ area()
| double VisiLibity::Polygon::area | ( | ) | const |
◆ bbox()
| Bounding_Box VisiLibity::Polygon::bbox | ( | ) | const |
◆ centroid()
| Point VisiLibity::Polygon::centroid | ( | ) | const |
◆ diameter()
| double VisiLibity::Polygon::diameter | ( | ) | const |
◆ eliminate_redundant_vertices()
| void VisiLibity::Polygon::eliminate_redundant_vertices | ( | double | epsilon = 0.0 | ) |
eliminates vertices which are (epsilon) - colinear with their respective neighbors
- Postcondition
- the Euclidean distance between each vertex and the line segment connecting its neighbors is at least epsilon, and the Polygon is in standard form
- Remarks
- time complexity O(n), where n is the number of vertices representing the the Polygon
◆ enforce_standard_form()
| void VisiLibity::Polygon::enforce_standard_form | ( | ) |
enforces that the lexicographically smallest vertex is first in the list of vertices representing the Polygon
- Remarks
- O(n) time complexity, where n is the number of vertices representing the Polygon. Lex. comparison is very sensitive to perturbations if two Points nearly define a line parallel to one of the axes
◆ is_in_standard_form()
| bool VisiLibity::Polygon::is_in_standard_form | ( | ) | const |
true iff lexicographically smallest vertex is first in the list of vertices representing the Polygon
- Remarks
- lex. comparison is very sensitive to perturbations if two Points nearly define a line parallel to one of the axes
◆ is_simple()
| bool VisiLibity::Polygon::is_simple | ( | double | epsilon = 0.0 | ) | const |
true iff Polygon is (epsilon) simple
- Remarks
- A Polygon is considered epsilon -simple iff (i) the Euclidean distance between nonadjacent edges is no greater than epsilon, (ii) adjacent edges intersect only at their single shared Point, (iii) and it has at least 3 vertices. One consequence of these conditions is that there can be no redundant vertices.
◆ n()
|
inline |
vertex count
- Remarks
- O(1) time complexity
◆ operator[]() [1/2]
|
inline |
access with automatic wrap-around in forward direction
- Remarks
- for efficiency, no bounds check; usually trying to access out of bounds causes a bus error
◆ operator[]() [2/2]
|
inline |
access with automatic wrap-around in forward direction
- Remarks
- For efficiency, no bounds check; usually trying to access out of bounds causes a bus error
◆ r()
| unsigned VisiLibity::Polygon::r | ( | ) | const |
reflex vertex count (nonconvex vertices)
- Remarks
- Works regardless of polygon orientation (ccw vs cw), but assumes no redundant vertices. Time complexity O(n), where n is the number of vertices representing the Polygon
◆ reverse()
| void VisiLibity::Polygon::reverse | ( | ) |
reverse (cyclic) order of vertices
- Remarks
- vertex first in list is held first
◆ write_to_file()
| void VisiLibity::Polygon::write_to_file | ( | const std::string & | filename, |
| int | fios_precision_temp = FIOS_PRECISION |
||
| ) |
write list of vertices to *.polygon file
- Precondition
- fios_precision_temp >=1
The documentation for this class was generated from the following files:
- src/visilibity.hpp
- src/visilibity.cpp
