Shamusworld >> Repos - architektonas/blob - src/base/infoarea.cpp

   1 // infoarea.cpp
   2 //
   3 // Part of the Architektonas Project
   4 // Originally part of QCad Community Edition by Andrew Mustun
   5 // Extensively rewritten and refactored by James L. Hammons
   6 // Portions copyright (C) 2001-2003 RibbonSoft
   7 // Copyright (C) 2010 Underground Software
   8 // See the README and GPLv2 files for licensing and warranty information
   9 //
  10 // JLH = James L. Hammons <jlhamm@acm.org>
  11 //
  12 // Who  When        What
  13 // ---  ----------  -----------------------------------------------------------
  14 // JLH  06/01/2010  Added this text. :-)
  15 //
  16
  17 #include "infoarea.h"
  18
  19 #include "mathextra.h"
  20 #include "debug.h"
  21
  22 /**
  23  * Constructor.
  24  */
  25 InfoArea::InfoArea()
  26 {
  27 }
  28
  29 /**
  30  * Destructor.
  31  */
  32 InfoArea::~InfoArea()
  33 {
  34 }
  35
  36 /**
  37  * Adds a point to the internal list
  38  *
  39  * @param p co-ordinate of the point
  40  */
  41 void InfoArea::addPoint(const Vector & p)
  42 {
  43         if (thePoints.empty())
  44                 baseY = p.y;
  45
  46         thePoints.append(p);
  47 }
  48
  49 /**
  50  * Resets the points.
  51  */
  52 void InfoArea::reset()
  53 {
  54         thePoints.clear();
  55         area = 0.0;
  56         circumference = 0.0;
  57 }
  58
  59 /**
  60  * Closes the polygon if it is not closed already.
  61  */
  62 void InfoArea::close()
  63 {
  64         if (isValid() && isClosed() == false)
  65         {
  66                 thePoints.append(thePoints.first());
  67
  68                 DEBUG->print("InfoArea::close: closed");
  69         }
  70 }
  71
  72 /**
  73  * @retval true If the area is closed (i.e. start point and end point are
  74  *   identical)
  75  * @retval false Otherwise.
  76  */
  77 bool InfoArea::isClosed()
  78 {
  79         return (thePoints.first().distanceTo(thePoints.last()) < 1.0e-4);
  80 }
  81
  82 /**
  83  * @retval true If the area is defined (i.e. there are at least 3 points)
  84  * @retval false If there are only two or less points.
  85  */
  86 bool InfoArea::isValid()
  87 {
  88         DEBUG->print("InfoArea::isValid: count: %d", thePoints.count());
  89         return (thePoints.count() > 2);
  90 }
  91
  92 /**
  93  * Calculates the area and the circumference of the area.
  94  */
  95 void InfoArea::calculate()
  96 {
  97         area = 0.0;
  98         circumference = 0.0;
  99         Vector ptFirst;
 100         Vector p1;
 101         Vector p2;
 102
 103         // at least 3 points needed for an area
 104         if (isValid())
 105         {
 106                 ptFirst = thePoints.last();
 107                 thePoints.pop_back();
 108
 109                 p1 = ptFirst;
 110
 111                 while (!thePoints.empty())
 112                 {
 113                         p2 = thePoints.last();
 114                         thePoints.pop_back();
 115
 116                         area += calcSubArea(p1, p2);
 117                         circumference += p1.distanceTo(p2);
 118                         //if (p1 != ptFirst) {
 119                         //      delete p1;
 120                         //}
 121                         p1 = p2;
 122                 }
 123
 124                 area += calcSubArea(p1, ptFirst);
 125                 circumference += p1.distanceTo(ptFirst);
 126                 //delete p1;
 127                 //delete ptFirst;
 128         }
 129
 130         //thePoints.clear();
 131         area = fabs(area);
 132 }
 133
 134 double InfoArea::getArea()
 135 {
 136         return area;
 137 }
 138
 139 double InfoArea::getCircumference()
 140 {
 141         return circumference;
 142 }
 143
 144 int InfoArea::count()
 145 {
 146         return thePoints.count();
 147 }
 148
 149 /**
 150  * Calculates a sub area.
 151  *
 152  * @param p1 first point
 153  * @param p2 second point
 154  */
 155 double InfoArea::calcSubArea(const Vector & p1, const Vector & p2)
 156 {
 157         double width = p2.x - p1.x;
 158         double height = (p1.y - baseY) + (p2.y - baseY);
 159
 160         return (width * height) / 2.0;
 161 }
 162
 163 /*! Calculates a distance
 164     \param _p1 first point
 165     \param _p2 second point
 166 */
 167 /*double
 168 InfoArea::calcDistance(Vector *_p1, Vector *_p2)
 169 {
 170         return mtGetDistance(_p1->getX(), _p1->getY(), _p2->getX(), _p2->getY());
 171 }*/