kig/misc/coordinate.h

   1 /**
   2  This file is part of Kig, a KDE program for Interactive Geometry...
   3  Copyright (C) 2002  Dominique Devriese <devriese@kde.org>
   4
   5  This program is free software; you can redistribute it and/or modify
   6  it under the terms of the GNU General Public License as published by
   7  the Free Software Foundation; either version 2 of the License, or
   8  (at your option) any later version.
   9
  10  This program is distributed in the hope that it will be useful,
  11  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  GNU General Public License for more details.
  14
  15  You should have received a copy of the GNU General Public License
  16  along with this program; if not, write to the Free Software
  17  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
  18  USA
  19 **/
  20
  21
  22 #ifndef KIG_MISC_COORDINATE_H
  23 #define KIG_MISC_COORDINATE_H
  24
  25 class QPoint;
  26 class kdbgstream;
  27
  28 /**
  29  * The Coordinate class is the basic class representing a 2D location
  30  * by its x and y components.  It has all relevant arithmetic
  31  * operators properly defined, and should be straightforward to use..
  32  */
  33 class Coordinate
  34 {
  35 public:
  36   static Coordinate fromQPoint( const QPoint& p );
  37
  38   /** Constructor.  Construct a new Coordinate, with a given x and y
  39    * value.
  40    */
  41   Coordinate( double x, double y );
  42   /** Copy Constructor.  Construct a new Coordinate, and give it the
  43    *  same value as p.
  44    */
  45   Coordinate( const Coordinate& p );
  46   /**
  47    * \ifnot creating-python-scripting-doc
  48    * \brief Default Constructor
  49    *
  50    * Constructs a new Coordinate, with x and y initialized to 0.
  51    * \endif
  52    */
  53   Coordinate();
  54   ~Coordinate() {};
  55
  56   /** Create an invalid Coordinate.  This is a special value of a
  57    * Coordinate that signals that something went wrong..
  58    *
  59    * \see Coordinate::valid
  60    *
  61    * \internal We represent an invalid coordinate by setting x or y to
  62    * positive or negative infinity.  This is handy, since it doesn't
  63    * require us to adapt most of the functions, it doesn't need extra
  64    * space, and most of the times that we should get an invalid coord,
  65    * we get one automatically..
  66    */
  67   static Coordinate invalidCoord();
  68   /** Return whether this is a valid Coordinate.
  69    * \see Coordinate::invalidCoord
  70    */
  71   bool valid() const;
  72
  73   /** Distance to another Coordinate.
  74    */
  75   double distance ( const Coordinate& p ) const;
  76   /** Length.  Returns the length or norm of this coordinate.
  77    * I.e. return the distance from this Coordinate to the origin.
  78    * \see squareLength
  79    */
  80   double length () const;
  81   /** Square length.  Equivalent to the square of \ref length, but a
  82    * bit more efficient because no square root has to be calculated.
  83    * \see length
  84    */
  85   inline double squareLength() const;
  86   /** Inverse.  Returns the inverse of this Coordinate.
  87    */
  88   const Coordinate operator- () const;
  89   /** Orthogonal.  Returns a vector which is orthogonal on this vector.
  90    * This relation always holds:
  91    * <pre>
  92    * Coordinate a = ...;
  93    * assert( a*a.orthogonal() ) == 0;
  94    * </pre>
  95    */
  96   const Coordinate orthogonal() const;
  97   /** Round. Returns this coordinate, rounded to the nearest integral
  98    * values.
  99    */
 100   const Coordinate round() const;
 101   /** Normalize.  This sets the length to length, while keeping the
 102    * x/y ratio untouched...
 103    */
 104   const Coordinate normalize( double length = 1 ) const;
 105   QPoint toQPoint() const;
 106
 107   Coordinate& operator= ( const Coordinate& c );
 108   /** Add.  Add c to this Coordinate
 109    */
 110   Coordinate& operator+= ( const Coordinate& c );
 111   /** Subtract.  Subtract c from this Coordinate
 112    */
 113   Coordinate& operator-= ( const Coordinate& c );
 114   /** Scale.  Scales this Coordinate by a factor r
 115    */
 116   Coordinate& operator*= ( double r );
 117   /** Scale.  Scales this Coordinate by a factor r
 118    */
 119   Coordinate& operator*= ( int r );
 120   /** Scale.  Scales this Coordinate by a factor 1/r
 121    */
 122   Coordinate& operator/= ( double r );
 123 public:
 124   /** X Component.  The X Component of this Coordinate.
 125    */
 126   double x;
 127   /** Y Component.  The Y Component of this Coordinate.
 128    */
 129   double y;
 130
 131   friend kdbgstream& operator<<( kdbgstream& s, const Coordinate& t );
 132   /** Add.  Returns the sum of a and b.
 133    */
 134   friend const Coordinate operator+ ( const Coordinate& a, const Coordinate& b );
 135   /** Subtract.  Returns the difference between a and b.
 136    */
 137   friend const Coordinate operator- ( const Coordinate& a, const Coordinate& b );
 138   /** Scale.  Returns this a, scaled by a factor of r.
 139    */
 140   friend const Coordinate operator* ( const Coordinate& a, double r );
 141   /** Scale.  Returns a, scaled by a factor of 1/r.
 142    */
 143   friend const Coordinate operator/ ( const Coordinate& a, double r );
 144   /** Scalar Product.  Returns the scalar product of a and b.
 145    */
 146   friend double operator*( const Coordinate& a, const Coordinate& b );
 147   /** Equal.  Tests two Coordinates for equality.
 148    */
 149   friend bool operator==( const Coordinate&, const Coordinate& );
 150   /** Not Equal.  Tests two Coordinates for inequality.
 151    */
 152   friend bool operator!=( const Coordinate&, const Coordinate& );
 153 };
 154
 155 const Coordinate operator/ ( const Coordinate& a, double r );
 156 kdbgstream& operator<<( kdbgstream& s, const Coordinate& t );
 157 const Coordinate operator+ ( const Coordinate& a, const Coordinate& b );
 158 const Coordinate operator- ( const Coordinate& a, const Coordinate& b );
 159 const Coordinate operator* ( const Coordinate& a, double r );
 160 const Coordinate operator* ( double r, const Coordinate& a );
 161 double operator*( const Coordinate& a, const Coordinate& b );
 162
 163 double Coordinate::squareLength() const
 164 {
 165   return x*x+y*y;
 166 }
 167
 168 #endif
 169