COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/include/xy.h @ 514:fd991a24c857

Last change on this file since 514:fd991a24c857 was 514:fd991a24c857, checked in by athos, 16 years ago

An awful mistake found and corrected.

File size: 4.9 KB
Line 
1// -*- c++ -*-
2#ifndef HUGO_XY_H
3#define HUGO_XY_H
4
5#include <iostream>
6
7///\ingroup misc
8///\file
9///\brief A simple two dimensional vector and a bounding box implementation
10///
11/// The class \ref hugo::xy "xy" implements
12///a two dimensional vector with the usual
13/// operations.
14///
15/// The class \ref hugo::BoundingBox "BoundingBox" can be used to determine
16/// the rectangular bounding box a set of \ref hugo::xy "xy"'s.
17///
18///\author Attila Bernath
19
20
21namespace hugo {
22
23  /// \addtogroup misc
24  /// @{
25
26  /// A two dimensional vector (plainvector) implementation
27
28  /// A two dimensional vector (plainvector) implementation
29  ///with the usual vector
30  /// operators.
31  ///
32  ///\author Attila Bernath
33  template<typename T>
34    class xy {
35
36    public:
37
38      T x,y;     
39     
40      ///Default constructor: both coordinates become 0
41      xy() : x(0), y(0) {}
42
43      ///Constructing the instance from coordinates
44      xy(T a, T b) : x(a), y(b) { }
45
46
47      ///Gives back the square of the norm of the vector
48      T normSquare(){
49        return x*x+y*y;
50      };
51 
52      ///Increments the left hand side by u
53      xy<T>& operator +=(const xy<T>& u){
54        x += u.x;
55        y += u.y;
56        return *this;
57      };
58 
59      ///Decrements the left hand side by u
60      xy<T>& operator -=(const xy<T>& u){
61        x -= u.x;
62        y -= u.y;
63        return *this;
64      };
65
66      ///Multiplying the left hand side with a scalar
67      xy<T>& operator *=(const T &u){
68        x *= u;
69        y *= u;
70        return *this;
71      };
72
73      ///Dividing the left hand side by a scalar
74      xy<T>& operator /=(const T &u){
75        x /= u;
76        y /= u;
77        return *this;
78      };
79 
80      ///Returns the scalar product of two vectors
81      T operator *(const xy<T>& u){
82        return x*u.x+y*u.y;
83      };
84 
85      ///Returns the sum of two vectors
86      xy<T> operator+(const xy<T> &u) const {
87        xy<T> b=*this;
88        return b+=u;
89      };
90
91      ///Returns the difference of two vectors
92      xy<T> operator-(const xy<T> &u) const {
93        xy<T> b=*this;
94        return b-=u;
95      };
96
97      ///Returns a vector multiplied by a scalar
98      xy<T> operator*(const T &u) const {
99        xy<T> b=*this;
100        return b*=u;
101      };
102
103      ///Returns a vector divided by a scalar
104      xy<T> operator/(const T &u) const {
105        xy<T> b=*this;
106        return b/=u;
107      };
108
109      ///Testing equality
110      bool operator==(const xy<T> &u){
111        return (x==u.x) && (y==u.y);
112      };
113
114      ///Testing inequality
115      bool operator!=(xy u){
116        return  (x!=u.x) || (y!=u.y);
117      };
118
119    };
120
121  ///Reading a plainvector from a stream
122  template<typename T>
123  inline
124  std::istream& operator>>(std::istream &is, xy<T> &z)
125  {
126
127    is >> z.x >> z.y;
128    return is;
129  }
130
131  ///Outputting a plainvector to a stream
132  template<typename T>
133  inline
134  std::ostream& operator<<(std::ostream &os, xy<T> z)
135  {
136    os << "(" << z.x << ", " << z.y << ")";
137    return os;
138  }
139
140
141  /// A class to calculate or store the bounding box of plainvectors.
142
143  /// A class to calculate or store the bounding box of plainvectors.
144  ///
145  ///\author Attila Bernath
146  template<typename T>
147    class BoundingBox {
148      xy<T> bottom_left, top_right;
149      bool _empty;
150    public:
151     
152      ///Default constructor: an empty bounding box
153      BoundingBox() { _empty = true; }
154
155      ///Constructing the instance from one point
156      BoundingBox(xy<T> a) { bottom_left=top_right=a; _empty = false; }
157
158      ///Is there any point added
159      bool empty() const {
160        return _empty;
161      }
162
163      ///Gives back the bottom left corner (if the bounding box is empty, then the return value is not defined)
164      xy<T> bottomLeft() const {
165        return bottom_left;
166      };
167
168      ///Gives back the top right corner (if the bounding box is empty, then the return value is not defined)
169      xy<T> topRight() const {
170        return top_right;
171      };
172
173      ///Checks whether a point is inside a bounding box
174      bool inside(const xy<T>& u){
175        if (_empty)
176          return false;
177        else{
178          return ((u.x-bottom_left.x)*(top_right.x-u.x) >= 0 &&
179                  (u.y-bottom_left.y)*(top_right.y-u.y) >= 0 );
180        }
181      }
182 
183      ///Increments a bounding box with a point
184      BoundingBox& operator +=(const xy<T>& u){
185        if (_empty){
186          bottom_left=top_right=u;
187          _empty = false;
188        }
189        else{
190          if (bottom_left.x > u.x) bottom_left.x = u.x;
191          if (bottom_left.y > u.y) bottom_left.y = u.y;
192          if (top_right.x < u.x) top_right.x = u.x;
193          if (top_right.y < u.y) top_right.y = u.y;
194        }
195        return *this;
196      };
197 
198      ///Sums a bounding box and a point
199      BoundingBox operator +(const xy<T>& u){
200        BoundingBox b = *this;
201        return b += u;
202      };
203
204      ///Increments a bounding box with an other bounding box
205      BoundingBox& operator +=(const BoundingBox &u){
206        if ( !u.empty() ){
207          *this += u.bottomLeft();
208          *this += u.topRight();
209        }
210        return *this;
211      };
212 
213      ///Sums two bounding boxes
214      BoundingBox operator +(const BoundingBox& u){
215        BoundingBox b = *this;
216        return b += u;
217      };
218
219    };//class Boundingbox
220
221
222  /// @}
223
224
225} //namespace hugo
226
227#endif //HUGO_XY_H
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