Rect Class Reference

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. More...

#include <rect.h>

Inheritance diagram for Rect:

List of all members.

Public Member Functions
	Rect ()
	To construct an empty Rect.
	Rect (INT32 LowX, INT32 LowY, INT32 HighX, INT32 HighY)
	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).
	Rect (const Coord &Low, UINT32 Width, UINT32 Height)
	To construct a rectangle with an inclusive lower left hand corner position of Low and a width and height as specified.
	Rect (const Coord &Low, const Coord &High)
	To construct a rectangle with an inclusive lower left hand corner position of Low and an exclusive upper right hand corner position of High.
	Rect (const Rect &Rect)
	Copy constructor.
Rect &	operator= (const Rect &Rect)
	Equals operator.
INT32	Width () const
	To find the width of the Rect.
INT32	Height () const
	To find the height of the Rect.
Coord	LowCorner () const
	To find the lower left hand coordinates of the Rect.
Coord	HighCorner () const
	To find the upper right hand coordinates of the Rect.
Coord	Centre () const
	To find the centre of the Rect It calculates Coord(lox+(width/2),loy+(height/2)).
BOOL	IsIntersectedWith (const Rect &) const
	To check for rectangle intersection.
Rect	Intersection (const Rect &) const
Rect	Union (const Rect &) const
INT32	SplitRect (const Rect &R, Rect *SubRects)
BOOL	ContainsCoord (const Coord &) const
	To check for coordinate containment.
BOOL	ContainsRectCoord (const Coord &) const
	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).
BOOL	ContainsRect (const Rect &) const
	To check for rectangle containment.
BOOL	IsAdjacent (const Rect &, MILLIPOINT Fuzzy) const
void	MakeEmpty ()
	Make the rectangle an empty one (all coordinates are set to 0).
BOOL	IsEmpty () const
	To check for empty rectangle.
BOOL	IsValid () const
	To check for a valid rectangle.
void	Inflate (INT32 XInc, INT32 YInc)
	Inflate a rectangle by given amounts. Negative values will deflate the rectangle.
void	Inflate (INT32 XInc)
	Inflate a rectangle by given amount. Negative values will deflate the rectangle.
void	Translate (INT32 XOfs, INT32 YOfs)
	Translate a rectangle by given offset.
void	IncludePoint (const Coord &)
INT32	operator== (const Rect &) const
	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.
INT32	operator!= (const Rect &) const
	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.
Public Attributes
Coord	lo
Coord	hi

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Detailed Description

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.

Author:

Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com> Date: 11/5/93

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.

Returns:

Errors: -

See also:

Coord

Rect

DocRect

WorkRect

OSRect

Definition at line 159 of file rect.h.

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Constructor & Destructor Documentation

Rect::Rect (   )  [inline]

To construct an empty Rect. Author: Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com> Date: 13/5/93 Parameters: None  [INPUTS] -  [OUTPUTS] Returns: - Errors: Definition at line 398 of file rect.h. { // An empty rectangle hi.x = hi.y = lo.x = lo.y = 0; }

Rect::Rect (  INT32  LowX, INT32  LowY, INT32  HighX, INT32  HighY )  [inline]

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). Author: Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com> Date: 13/5/93 Parameters: LowX  : Lower X coord of rectangle (inclusive) [INPUTS] HighX: Higher X coord of rectangle (exclusive) LowY : Lower Y coord of rectangle (inclusive) HighY: Higher Y coord of rectangle (exclusive) -  [OUTPUTS] Returns: - 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. Definition at line 429 of file rect.h. { // 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, UINT32  Width, UINT32  Height )  [inline]

To construct a rectangle with an inclusive lower left hand corner position of Low and a width and height as specified. Author: Tim_Browse (Xara Group Ltd) <camelotdev@xara.com> Date: 17/5/93 Parameters: Low,:  Coordinates of the inclusive lower left hand corner. [INPUTS] Width, Height : Desired dimensions of the rectangle. -  [OUTPUTS] Returns: - Errors: None. Definition at line 494 of file rect.h. { lo = Low; hi.x = lo.x + Width; hi.y = lo.y + Height; }

Rect::Rect (  const Coord &  Low, const Coord &  High )  [inline]

To construct a rectangle with an inclusive lower left hand corner position of Low and an exclusive upper right hand corner position of High. Author: Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com> Date: 13/5/93 Parameters: Low  : Coordinates of the lower left hand corner (inclusive) [INPUTS] High: Coordinates of the upper right hand corner (exclusive) -  [OUTPUTS] Returns: - 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. Definition at line 464 of file rect.h. { // 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 Rect &  R  )  [inline]

Copy constructor. Author: Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com> Date: 13/5/93 Parameters: R,:  The copy of the Rect [INPUTS] -  [OUTPUTS] Returns: - Definition at line 519 of file rect.h. { lo = R.lo; hi = R.hi; }

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Member Function Documentation

Coord Rect::Centre (   )  const [inline]

To find the centre of the Rect It calculates Coord(lox+(width/2),loy+(height/2)). Author: Mark_Neves (Xara Group Ltd) <camelotdev@xara.com> Date: 19/5/99 Parameters: -  [INPUTS] -  [OUTPUTS] Returns: The centre coord of this Rect Errors: Assertion failure if the rectangle is invalid. Definition at line 667 of file rect.h. { // 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::ContainsCoord (  const Coord &  Point  )  const [inline]

To check for coordinate containment. Author: Tim_Browse (Xara Group Ltd) <camelotdev@xara.com> Date: 17/5/93 Parameters: -  [INPUTS] -  [OUTPUTS] Returns: TRUE if the coordinate is within the rectangle, FALSE otherwise. Errors: Assertion failure if the rectangle is invalid. See also: ContainsRectCoord; ContainsRect Definition at line 725 of file rect.h. { // 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::ContainsRect (  const Rect &  Rect  )  const [inline]

To check for rectangle containment. Author: Tim_Browse (Xara Group Ltd) <camelotdev@xara.com> Date: 17/5/93 Parameters: -  [INPUTS] -  [OUTPUTS] Returns: TRUE if the rectangle 'Rect' is within the rectangle, FALSE otherwise. Errors: Assertion failure if the rectangle is invalid. See also: ContainsRectCoord; ContainsCoord Definition at line 795 of file rect.h. { // 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)); }

BOOL Rect::ContainsRectCoord (  const Coord &  Point  )  const [inline]

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). Author: Tim_Browse (Xara Group Ltd) <camelotdev@xara.com> Date: 17/5/93 Parameters: -  [INPUTS] -  [OUTPUTS] Returns: TRUE if the coordinate is within the rectangle, FALSE otherwise. Errors: Assertion failure if the rectangle is invalid. See also: ContainsCoord; ContainsRect Definition at line 761 of file rect.h. { // 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)); }

INT32 Rect::Height (   )  const [inline]

To find the height of the Rect. Author: Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com> Date: 13/5/93 Parameters: -  [INPUTS] -  [OUTPUTS] Returns: The height of the Rect Definition at line 589 of file rect.h. { // Detect an invalid rectangle ENSURE(IsValid(), "Rect::Height() was called on\nan invalid rectangle."); return(hi.y - lo.y); }

Coord Rect::HighCorner (   )  const [inline]

To find the upper right hand coordinates of the Rect. Author: Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com> Date: 13/5/93 Parameters: -  [INPUTS] -  [OUTPUTS] Returns: The exclusive upper right hand coordinates of the Rect Errors: Assertion failure if the rectangle is invalid. Definition at line 640 of file rect.h. { // Detect an invalid rectangle ENSURE(IsValid(), "Rect::HighCorner() was called on\nan invalid rectangle."); return(hi); }

void Rect::IncludePoint (  const Coord &   )

void Rect::Inflate (  INT32  Inc  )  [inline]

Inflate a rectangle by given amount. Negative values will deflate the rectangle. Author: Tim_Browse (Xara Group Ltd) <camelotdev@xara.com> Date: 17/5/93 Parameters: Inc  - the amount to inflate (or deflate) the rectangle by. [INPUTS] -  [OUTPUTS] Returns: N/A. Errors: An assertion failure if the rectangle is invalid. Definition at line 367 of file rect.h. { // 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; }

void Rect::Inflate (  INT32  XInc, INT32  YInc )  [inline]

Inflate a rectangle by given amounts. Negative values will deflate the rectangle. Author: Tim_Browse (Xara Group Ltd) <camelotdev@xara.com> Date: 17/5/93 Parameters: XInc,YInc  - the amount to inflate (or deflate) the rectangle by. [INPUTS] -  [OUTPUTS] Returns: N/A. Errors: An assertion failure if the rectangle is invalid. Definition at line 335 of file rect.h. { // 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; }

Rect Rect::Intersection (  const Rect &   )  const

BOOL Rect::IsAdjacent (  const Rect &  , MILLIPOINT  Fuzzy )  const

BOOL Rect::IsEmpty (   )  const [inline]

To check for empty rectangle. Author: Tim_Browse (Xara Group Ltd) <camelotdev@xara.com> Date: 17/5/93 Parameters: -  [INPUTS] -  [OUTPUTS] Returns: TRUE if the rectangle is empty. Errors: Definition at line 845 of file rect.h. { return ((lo.x == hi.x) || (lo.y == hi.y)); }

BOOL Rect::IsIntersectedWith (  const Rect &  R  )  const [inline]

To check for rectangle intersection. Author: Tim_Browse (Xara Group Ltd) <camelotdev@xara.com> Date: 17/5/93 Parameters: -  [INPUTS] -  [OUTPUTS] Returns: TRUE if the rectangles intersect, FALSE otherwise. Errors: Definition at line 694 of file rect.h. { // 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::IsValid (   )  const [inline]

To check for a valid rectangle. Author: Tim_Browse (Xara Group Ltd) <camelotdev@xara.com> Date: 9/6/93 Parameters: -  [INPUTS] -  [OUTPUTS] Returns: TRUE if the rectangle is valid. Errors: Definition at line 869 of file rect.h. { return ((lo.x <= hi.x) && (lo.y <= hi.y)); }

Coord Rect::LowCorner (   )  const [inline]

To find the lower left hand coordinates of the Rect. Returns: Errors: Assertion failure if the rectangle is invalid. Definition at line 614 of file rect.h. { // Detect an invalid rectangle ENSURE(IsValid(), "Rect::LowCorner() was called on\nan invalid rectangle."); return(lo); }

void Rect::MakeEmpty (   )  [inline]

Make the rectangle an empty one (all coordinates are set to 0). Author: Tim_Browse (Xara Group Ltd) <camelotdev@xara.com> Date: 03/03/94 See also: Rect::MakeEmpty Definition at line 821 of file rect.h. { lo.x = lo.y = hi.x = hi.y = 0; }

INT32 Rect::operator!= (  const Rect &  R  )  const [inline]

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. Author: Tim_Browse (Xara Group Ltd) <camelotdev@xara.com> Date: 17/5/93 Parameters: R  - the rectangle to compare against. [INPUTS] -  [OUTPUTS] Returns: TRUE if R does not describe the same rectangle as the object. Friend: Rect Returns: Errors: None. Definition at line 305 of file rect.h. { // 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)); }

Rect & Rect::operator= (  const Rect &  Rect  )  [inline]

Equals operator. Author: Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com> Date: 13/5/93 Parameters: Rect,:  Rect to copy [INPUTS] -  [OUTPUTS] Returns: Reference to this Rect Definition at line 541 of file rect.h. { lo = Rect.lo; hi = Rect.hi; return *this; }

INT32 Rect::operator== (  const Rect &  R  )  const [inline]

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. Author: Tim_Browse (Xara Group Ltd) <camelotdev@xara.com> Date: 17/5/93 Parameters: R  - the rectangle to compare against. [INPUTS] -  [OUTPUTS] Returns: TRUE if R is describes the same rectangle as the object. Friend: Rect Returns: Errors: None. Definition at line 270 of file rect.h. { // 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 Rect::SplitRect (  const Rect &  R, Rect *  SubRects )

void Rect::Translate (  INT32  XOfs, INT32  YOfs )  [inline]

Translate a rectangle by given offset. Author: Tim_Browse (Xara Group Ltd) <camelotdev@xara.com> Date: 17/5/93 Parameters: (XOfs,YOfs)  - the offset to translate the rectangle by. [INPUTS] -  [OUTPUTS] Returns: N/A. Errors: An assertion failure if the rectangle is invalid. Definition at line 235 of file rect.h. { // 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; }

Rect Rect::Union (  const Rect &   )  const

INT32 Rect::Width (   )  const [inline]

To find the width of the Rect. Author: Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com> Date: 13/5/93 Parameters: -  [INPUTS] -  [OUTPUTS] Returns: The width of the Rect Definition at line 565 of file rect.h. { // Detect an invalid rectangle ENSURE(IsValid(), "Rect::Width() was called on\nan invalid rectangle."); return (hi.x - lo.x); }

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Member Data Documentation

Coord Rect::hi

Definition at line 164 of file rect.h.

Coord Rect::lo

Definition at line 163 of file rect.h.

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The documentation for this class was generated from the following file:

• Kernel/rect.h (r1785/r751)

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