libs/cassowary/cassowary/ClLinearEquation.h

   1 // $Id$
   2 //
   3 // Cassowary Incremental Constraint Solver
   4 // Original Smalltalk Implementation by Alan Borning
   5 // This C++ Implementation by Greg J. Badros, <gjb@cs.washington.edu>
   6 // http://www.cs.washington.edu/homes/gjb
   7 // (C) 1998, 1999 Greg J. Badros and Alan Borning
   8 // See ../LICENSE for legal details regarding this software
   9 //
  10 // ClLinearEquation.h
  11
  12 #ifndef ClLinearEquation_H
  13 #define ClLinearEquation_H
  14
  15 #if defined(HAVE_CONFIG_H) && !defined(CONFIG_H_INCLUDED) && !defined(CONFIG_INLINE_H_INCLUDED)
  16 #include <cassowary/config-inline.h>
  17 #define CONFIG_INLINE_H_INCLUDED
  18 #endif
  19
  20 #include "Cassowary.h"
  21 #include "ClLinearConstraint.h"
  22 #include "ClLinearExpression.h"
  23
  24 class ClStrength;
  25 class ClVariable;
  26
  27 class ClLinearEquation : public ClLinearConstraint {
  28  private: typedef ClLinearConstraint super;
  29
  30  public:
  31  //// Constructors
  32
  33  // ClLinearEquation(expr,...)    is   expr == 0
  34  ClLinearEquation(const ClLinearExpression &cle,
  35                   const ClStrength &strength = ClsRequired(),
  36                   double weight = 1.0) :
  37    ClLinearConstraint(cle,strength, weight)
  38    { }
  39
  40  // ClLinearEquation(var,expr,...)  is   var == expr
  41  ClLinearEquation(ClVariable clv,
  42                   const ClLinearExpression &cle,
  43                   const ClStrength &strength = ClsRequired(),
  44                   double weight = 1.0) :
  45    ClLinearConstraint(cle,strength,weight)
  46    { _expression.AddVariable(clv,-1.0); }
  47
  48  // ClLinearEquation(expr,var,...) is   var == expr
  49  ClLinearEquation(const ClLinearExpression &cle,
  50                   ClVariable clv,
  51                   const ClStrength &strength = ClsRequired(),
  52                   double weight = 1.0) :
  53    ClLinearConstraint(cle,strength,weight)
  54    { _expression.AddVariable(clv,-1.0); }
  55
  56  // ClLinearEquation(expr,expr,...) is   expr == expr
  57  ClLinearEquation(const ClLinearExpression &cle1,
  58                   const ClLinearExpression &cle2,
  59                   const ClStrength &strength = ClsRequired(),
  60                   double weight = 1.0) :
  61    ClLinearConstraint(cle1,strength,weight)
  62    { _expression.AddExpression(cle2,-1.0); }
  63
  64 #ifndef CL_NO_IO
  65  virtual ostream &PrintOn(ostream &xo) const
  66    {  super::PrintOn(xo); xo << " = 0 )"; return xo; }
  67 #endif
  68
  69   virtual bool FIsSatisfied() const
  70     { return (_expression.Evaluate() == 0); }
  71
  72 };
  73
  74 #endif