rect.h

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// $Id: rect.h 751 2006-03-31 15:43:49Z alex $
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#ifndef INC_RECT
#define INC_RECT

#include "coord.h"

/***********************************************************************************************

>    Class Rect

     Author:       Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com>
     Date:         11/5/93
     
     Purpose:      This class is used to represent a rectangular region.  It uses a union to
                   enable the client to access the rectangle as two Coords (lo and hi) or as
                   four INT32s (lox, loy, hix, hiy).  An anonymous union is used, which is a
                   defined C++ feature and so portable.

                   The lo coordinates are inclusive, whilst the hi coordinates are exclusive.
                   In the document space, lo.y <= hi.y and lo.x <= hi.x (the inequalities are 
                   not strict because rectangles can have zero width and/or height - such
                   rectangles are considered perfectly valid). 
                   
                   The inclusivity can be explained as follows:
                   
                   A point at (lo.x, lo.y) is inside the rectangle
                   A point at (hi.x, hi.y) is outside the rectangle
                   
                   Any rectangle that does not obey the inequalites lo.y <= hi.y and 
                   lo.x <= hi.x is deemed to be 'invalid'.  Invalid rectangles have special
                   properties.  They will cause errors when used in some operations, but not
                   in others.  The general rule is that if the rectangle is used as an entity,
                   then the operation will succeed (taking account of the 'invalidity' of
                   the rectangle).  If, however, the actual coordinates of the invalid
                   rectangle must be used/changed in the operation, then an error (usually an
                   assertion failure) will occur.
                   
                   For example, using invalid rectangles in Unions and Intersections is ok, 
                   because the invalid rectangle is ignored, and the 'other' rectangle is
                   returned as the result.  This means that if both rectangles are invalid,
                   then an invalid rectangle is returned.
                   
                   Conversely, trying to use operations like Translate(), Inflate(), Width()
                   or Height() on invalid rectangles is considered to be an error, and will
                   cause an assertion failure.
                   
                   See the individual function descriptions for more details.
                   
                   
     Errors:       -

     SeeAlso:      Coord

     SeeAlso:      Rect
     SeeAlso:      DocRect
     SeeAlso:      WorkRect
     SeeAlso:      OSRect
                    
***********************************************************************************************/

class CAMAPI Rect
{   
public:

    Coord               lo;
    Coord               hi;
                            
    // Rect constructors
                        
    Rect();              

    Rect(INT32 LowX, INT32 LowY, INT32 HighX, INT32 HighY); 

    Rect(const Coord& Low, UINT32 Width, UINT32 Height); 

    Rect(const Coord& Low, const Coord& High);   
                     
    Rect(const Rect& Rect); // Copy constructor

    Rect& operator=(const Rect& Rect);// Assignment operator
                     
    INT32 Width() const;
    INT32 Height() const; 
    
    Coord LowCorner() const;
    Coord HighCorner() const;  

    Coord Centre() const;
    
    // General operations type stuff
    BOOL IsIntersectedWith(const Rect&) const;
    Rect Intersection(const Rect&) const;
    Rect Union(const Rect&) const;
    INT32 SplitRect(const Rect& R, Rect* SubRects);

    BOOL ContainsCoord(const Coord&) const;
    BOOL ContainsRectCoord(const Coord&) const;
    BOOL ContainsRect(const Rect&) const;
    BOOL IsAdjacent(const Rect&, MILLIPOINT Fuzzy) const;

    void MakeEmpty();
        
    BOOL IsEmpty() const;   
    BOOL IsValid() const;   

    void Inflate(INT32 XInc, INT32 YInc);
    void Inflate(INT32 XInc);
    void Translate(INT32 XOfs, INT32 YOfs);
    void IncludePoint(const Coord&);
    
    // Overloaded operators
    INT32 operator==(const Rect&) const;
    INT32 operator!=(const Rect&) const;


};                                            


  
/*********************************************************************************************

>    void Rect::Translate(INT32 XOfs, INT32 YOfs)

     Author:    Tim_Browse (Xara Group Ltd) <camelotdev@xara.com>
     Created:   17/5/93
     Inputs:    (XOfs, YOfs) - the offset to translate the rectangle by.
     Outputs:   - 
     
     Returns:   N/A.
                
     Purpose:   Translate a rectangle by given offset.

     Errors:    An assertion failure if the rectangle is invalid.

**********************************************************************************************/  

inline void Rect::Translate(INT32 XOfs, INT32 YOfs)
{
    // Detect an invalid rectangle
    ENSURE(IsValid(), "Rect::Translate() was called on an \ninvalid rectangle.");  

    lo.x += XOfs;
    lo.y += YOfs;
    
    hi.x += XOfs;
    hi.y += YOfs;
}



/*********************************************************************************************

>    INT32 operator==(const Rect& R) const

     Author:    Tim_Browse (Xara Group Ltd) <camelotdev@xara.com>
     Created:   17/5/93
     Inputs:    R - the rectangle to compare against.
     Outputs:   - 
     
     Returns:   TRUE if R is describes the same rectangle as the object.
                
     Purpose:   Test for equality of two rectangles.  As all invalid rectangles have the
                same results when used for Union/Intersection, any two invalid rectangles
                are considered equal.

     Friend:    Rect
     
     Errors:    None.

**********************************************************************************************/  

inline INT32 Rect::operator==(const Rect& R) const
{
    // Invalid rectangles are equal
    if ((!IsValid()) && (!R.IsValid()))
        return TRUE;
        
    // Could use structure compare? Would it be portable? Probably not...
    
    return ((lo.x == R.lo.x) && (lo.y == R.lo.y) &&
            (hi.x == R.hi.x) && (hi.y == R.hi.y));
}



/*********************************************************************************************

>    INT32 operator!=(const Rect& R) const

     Author:    Tim_Browse (Xara Group Ltd) <camelotdev@xara.com>
     Created:   17/5/93
     Inputs:    R - the rectangle to compare against.
     Outputs:   - 
     
     Returns:   TRUE if R does not describe the same rectangle as the object.
                
     Purpose:   Test for inequality of two rectangles.  As all invalid rectangles have the
                same results when used for Union/Intersection, any two invalid rectangles
                are considered equal.

     Friend:    Rect
     
     Errors:    None.

**********************************************************************************************/  

inline INT32 Rect::operator!=(const Rect& R) const
{
    // Invalid rectangles are equal
    if ((!IsValid()) && (!R.IsValid()))
        return FALSE;
        
    return ((lo.x != R.lo.x) || (lo.y != R.lo.y) ||
            (hi.x != R.hi.x) || (hi.y != R.hi.y));
}



/*********************************************************************************************

>    void Rect::Inflate(INT32 XInc, INT32 YInc)

     Author:    Tim_Browse (Xara Group Ltd) <camelotdev@xara.com>
     Created:   17/5/93
     Inputs:    XInc, YInc - the amount to inflate (or deflate) the rectangle by.
     Outputs:   - 
     
     Returns:   N/A.
                
     Purpose:   Inflate a rectangle by given amounts.  Negative values will deflate the
                rectangle.

     Errors:    An assertion failure if the rectangle is invalid.

**********************************************************************************************/  

inline void Rect::Inflate(INT32 XInc, INT32 YInc)
{
    // Detect an invalid rectangle
    ENSURE(IsValid(), "Rect::Inflate(INT32, INT32) was called on an \ninvalid rectangle.");  

    lo.x -= XInc;
    lo.y -= YInc;
    
    hi.x += XInc;
    hi.y += YInc;
}



/*********************************************************************************************

>    void Rect::Inflate(INT32 Inc)

     Author:    Tim_Browse (Xara Group Ltd) <camelotdev@xara.com>
     Created:   17/5/93
     Inputs:    Inc - the amount to inflate (or deflate) the rectangle by.
     Outputs:   - 
     
     Returns:   N/A.
                
     Purpose:   Inflate a rectangle by given amount.  Negative values will deflate the
                rectangle.

     Errors:    An assertion failure if the rectangle is invalid.

**********************************************************************************************/  

inline void Rect::Inflate(INT32 Inc)
{
    // Detect an invalid rectangle
    ENSURE(IsValid(), "Rect::Inflate(INT32) was called on an \ninvalid rectangle.");  

    lo.x -= Inc;
    lo.y -= Inc;
    
    hi.x += Inc;
    hi.y += Inc;
}



/*********************************************************************************************

>    Rect::Rect() 

     Author:    Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com>
     Created:   13/5/93
     Inputs:    None
     Outputs:   -
     Returns:   - 
                
     Purpose:   To construct an empty Rect.
                

     Errors:    

**********************************************************************************************/  

inline Rect::Rect()
{
    // An empty rectangle
    hi.x = hi.y = lo.x = lo.y = 0;
}
     
                

/*********************************************************************************************
           
>    Rect::Rect(INT32 LowX, INT32 LowY, INT32 HighX, INT32 HighY)

     Author:    Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com>
     Created:   13/5/93
     Inputs:    LowX : Lower X coord of rectangle (inclusive)
                HighX: Higher X coord of rectangle (exclusive) 
                LowY : Lower Y coord of rectangle (inclusive)
                HighY: Higher Y coord of rectangle (exclusive)
                
     Outputs:   -
     Returns:   - 
                
     Purpose:   To construct a Rect with an inclusive lower left hand corner 
                position of (Left, Lower) and an exclusive upper right hand corner 
                position of (Right, Upper).  

     Errors:    An assertion failure will occur if the lower left hand coordinates
                are not lower than and to the left of the upper right coordinate. 

**********************************************************************************************/  
                      
inline Rect::Rect(INT32 LowX, INT32 LowY, INT32 HighX, INT32 HighY)
{                               
    // Defensive programming, detect an invalid rectangle
    ENSURE((LowX <= HighX) && (LowY <= HighY),
           "Rect::Rect(INT32, INT32, INT32, INT32) was\n passed invalid coordinates");  
    
    lo.x = LowX;
    lo.y = LowY; 
    
    hi.x = HighX; 
    hi.y = HighY;   
} 



/*********************************************************************************************
           
>    Rect::Rect(const Coord& Low, const Coord& High) 

     Author:    Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com>
     Created:   13/5/93
     Inputs:    Low : Coordinates of the lower left hand corner (inclusive) 
                High: Coordinates of the upper right hand corner (exclusive)
     Outputs:   -
     Returns:   - 
                
     Purpose:   To construct a rectangle with an inclusive lower left hand corner 
                position of Low and an exclusive upper right hand corner
                position of High.

     Errors:    An assertion failure will occur if the lower left hand coordinates
                are not lower than and to the left of the upper right coordinates. 

**********************************************************************************************/  

inline Rect::Rect(const Coord& Low, const Coord& High)
{         
    // Defensive programming, detect an invalid rectangle
    ENSURE((Low.x <= High.x) && (Low.y <= High.y),
           "Rect::Rect(Coord, Coord) was\n passed invalid coordinates");  
    
    lo = Low;
    hi = High;
}       
    


/*********************************************************************************************
           
>    Rect::Rect(const Coord& Low, UINT32 Width, UINT32 Height) 

     Author:    Tim_Browse (Xara Group Ltd) <camelotdev@xara.com>
     Created:   17/5/93
     Inputs:    Low: Coordinates of the inclusive lower left hand corner.
                Width, Height  : Desired dimensions of the rectangle.
     Outputs:   -
     Returns:   - 
                
     Purpose:   To construct a rectangle with an inclusive lower left hand corner 
                position of Low and a width and height as specified.

     Errors:    None.
     
**********************************************************************************************/  

inline Rect::Rect(const Coord& Low, UINT32 Width, UINT32 Height) 
{         
    lo = Low;
    
    hi.x = lo.x + Width;
    hi.y = lo.y + Height;
}       
   
   
    
       
/*********************************************************************************************
           
>    Rect::Rect(const Rect& R) 

     Author:    Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com>
     Created:   13/5/93
     Inputs:    R: The copy of the Rect 
     Outputs:   -
     Returns:   - 
                
     Purpose:   Copy constructor 

**********************************************************************************************/  

inline Rect::Rect(const Rect& R)
{
    lo = R.lo;
    hi = R.hi;
}



/*********************************************************************************************
           
>    Rect& Rect::operator=(const Rect& Rect)

     Author:    Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com>
     Created:   13/5/93
     Inputs:    Rect: Rect to copy 
     Outputs:   -
     Returns:   Reference to this Rect 
                
     Purpose:   Equals operator 

**********************************************************************************************/  

inline Rect& Rect::operator=(const Rect& Rect)
{                                                    
    lo = Rect.lo; 
    hi = Rect.hi;
    
    return *this; 
}



/*********************************************************************************************
           
>    INT32 Rect::Width() const

     Author:    Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com>
     Created:   13/5/93
     Inputs:    - 
     Outputs:   -
     Returns:   The width of the Rect 
                
     Purpose:   To find the width of the Rect 

**********************************************************************************************/  
                     
inline INT32 Rect::Width() const
{
    // Detect an invalid rectangle
    ENSURE(IsValid(), "Rect::Width() was called on\nan invalid rectangle.");  

    return (hi.x - lo.x);   
}       



/*********************************************************************************************
           
>    INT32 Rect::Height() const

     Author:    Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com>
     Created:   13/5/93
     Inputs:    - 
     Outputs:   -
     Returns:   The height of the Rect 
                
     Purpose:   To find the height of the Rect 

**********************************************************************************************/  

inline INT32 Rect::Height() const 
{                      
    // Detect an invalid rectangle
    ENSURE(IsValid(), "Rect::Height() was called on\nan invalid rectangle.");  

    return(hi.y - lo.y); 
}
                     


/*********************************************************************************************
           
>    Coord Rect::LowCorner() const
     Author:    Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com>
     Created:   13/5/93
     Inputs:    - 
     Outputs:   -
     Returns:   The inclusive lower left hand coordinates of the Rect
                
     Purpose:   To find the lower left hand coordinates of the Rect
     
     Errors:    Assertion failure if the rectangle is invalid.

**********************************************************************************************/  
                     
inline Coord Rect::LowCorner() const
{     
    // Detect an invalid rectangle
    ENSURE(IsValid(), "Rect::LowCorner() was called on\nan invalid rectangle.");  

    return(lo); 
}        



/*********************************************************************************************
           
>    Coord Rect::HighCorner() const  

     Author:    Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com>
     Created:   13/5/93
     Inputs:    - 
     Outputs:   -
     Returns:   The exclusive upper right hand coordinates of the Rect 
                
     Purpose:   To find the upper right hand coordinates of the Rect

     Errors:    Assertion failure if the rectangle is invalid.

**********************************************************************************************/  

inline Coord Rect::HighCorner() const  
{      
    // Detect an invalid rectangle
    ENSURE(IsValid(), "Rect::HighCorner() was called on\nan invalid rectangle.");  

    return(hi); 
}                  



/*********************************************************************************************
           
>    Coord Rect::Centre() const

     Author:    Mark_Neves (Xara Group Ltd) <camelotdev@xara.com>
     Created:   19/5/99
     Inputs:    - 
     Outputs:   -
     Returns:   The centre coord of this Rect
                
     Purpose:   To find the centre of the Rect
                It calculates Coord(lox+(width/2),loy+(height/2))
     
     Errors:    Assertion failure if the rectangle is invalid.

**********************************************************************************************/  
                     
inline Coord Rect::Centre() const
{     
    // Detect an invalid rectangle
    ENSURE(IsValid(), "Rect::Centre() was called on\nan invalid rectangle.");  

    return Coord(lo.x + Width() / 2, lo.y + Height() / 2); 
}        



/*********************************************************************************************

>    BOOL Rect::IsIntersectedWith(const Rect& Rect) const

     Author:    Tim_Browse (Xara Group Ltd) <camelotdev@xara.com>
     Created:   17/5/93
     Inputs:    -  
     Outputs:   - 
     
     Returns:   TRUE if the rectangles intersect, FALSE otherwise.
                
     Purpose:   To check for rectangle intersection 

     Errors:    

**********************************************************************************************/  

inline BOOL Rect::IsIntersectedWith(const Rect& R) const
{
    // Detect an invalid rectangle
    if ((!IsValid()) || (!R.IsValid()))
        return FALSE;
        
    return ((hi.x > R.lo.x) && (lo.x < R.hi.x) &&
            (hi.y > R.lo.y) && (lo.y < R.hi.y));
}



/*********************************************************************************************

>    BOOL Rect::ContainsCoord(const Coord& Point)

     Author:    Tim_Browse (Xara Group Ltd) <camelotdev@xara.com>
     Created:   17/5/93
     Inputs:    -  
     Outputs:   - 
     
     Returns:   TRUE if the coordinate is within the rectangle, FALSE otherwise.
                
     Purpose:   To check for coordinate containment.

     Errors:    Assertion failure if the rectangle is invalid.

     SeeAlso:   ContainsRectCoord; ContainsRect

**********************************************************************************************/  

inline BOOL Rect::ContainsCoord(const Coord& Point) const
{
    // Check for an an empty rectangle
    if (IsEmpty())
        return FALSE;

    // Detect an invalid rectangle
    ENSURE(IsValid(), "Rect::ContainsCoord() was called on\nan invalid rectangle.");  

    return ((Point.x >= lo.x) && (Point.x < hi.x) &&
            (Point.y >= lo.y) && (Point.y < hi.y));
}



/*********************************************************************************************

>    BOOL Rect::ContainsRectCoord(const Coord& Point)

     Author:    Tim_Browse (Xara Group Ltd) <camelotdev@xara.com>
     Created:   17/5/93
     Inputs:    -  
     Outputs:   - 
     
     Returns:   TRUE if the coordinate is within the rectangle, FALSE otherwise.
                
     Purpose:   To check for coordinate containment.  This will work for coordinates which
                have been extracted from other rectangles (i.e. the top right corner is
                considered inclusive for this operation, not exclusive).

     Errors:    Assertion failure if the rectangle is invalid.

     SeeAlso:   ContainsCoord; ContainsRect

**********************************************************************************************/  

inline BOOL Rect::ContainsRectCoord(const Coord& Point) const
{
    // Check for an an empty rectangle
    if (IsEmpty())
        return FALSE;

    // Detect an invalid rectangle
    ENSURE(IsValid(), "Rect::ContainsRectCoord() was called on\nan invalid rectangle.");  

    return ((Point.x >= lo.x) && (Point.x <= hi.x) &&
            (Point.y >= lo.y) && (Point.y <= hi.y));
}



/*********************************************************************************************

>    BOOL Rect::ContainsRect(const Rect& Rect)

     Author:    Tim_Browse (Xara Group Ltd) <camelotdev@xara.com>
     Created:   17/5/93
     Inputs:    -  
     Outputs:   - 
     
     Returns:   TRUE if the rectangle 'Rect' is within the rectangle, FALSE otherwise.
                
     Purpose:   To check for rectangle containment.

     Errors:    Assertion failure if the rectangle is invalid.

     SeeAlso:   ContainsRectCoord; ContainsCoord

**********************************************************************************************/  

inline BOOL Rect::ContainsRect(const Rect& Rect) const
{
    // Check for an an empty rectangle
    if (IsEmpty())
        return FALSE;

    // Detect an invalid rectangle
    ENSURE(IsValid(), "Rect::ContainsRect() was called on\nan invalid rectangle.");  

    return ((Rect.lo.x >= lo.x) && (Rect.hi.x <= hi.x) &&
            (Rect.lo.y >= lo.y) && (Rect.hi.y <= hi.y));
}



/********************************************************************************************

>   void Rect::MakeEmpty()

    Author:     Tim_Browse (Xara Group Ltd) <camelotdev@xara.com>
    Created:    03/03/94
    Purpose:    Make the rectangle an empty one (all coordinates are set to 0).
    SeeAlso:    Rect::MakeEmpty

********************************************************************************************/

inline void Rect::MakeEmpty()
{
  lo.x = lo.y = hi.x = hi.y = 0;
}



/*********************************************************************************************

>    BOOL Rect::IsEmpty() const

     Author:    Tim_Browse (Xara Group Ltd) <camelotdev@xara.com>
     Created:   17/5/93
     Inputs:    -  
     Outputs:   - 
     
     Returns:   TRUE if the rectangle is empty.
                
     Purpose:   To check for empty rectangle.

     Errors:    

**********************************************************************************************/  

inline BOOL Rect::IsEmpty() const
{
    return ((lo.x == hi.x) || (lo.y == hi.y));
}



/*********************************************************************************************

>    BOOL Rect::IsValid() const

     Author:    Tim_Browse (Xara Group Ltd) <camelotdev@xara.com>
     Created:   9/6/93
     Inputs:    -  
     Outputs:   - 
     
     Returns:   TRUE if the rectangle is valid.
                
     Purpose:   To check for a valid rectangle.

     Errors:    

**********************************************************************************************/  

inline BOOL Rect::IsValid() const
{
    return ((lo.x <= hi.x) && (lo.y <= hi.y));
}

#endif

---