TRect Class Reference

#include <e32std.h>

class TRect

Public Attributes
TPoint	iBr
TPoint	iTl

Public Member Enumerations
enum	TUninitialized { EUninitialized }

Public Member Functions
	TRect(TUninitialized)
	TRect()
	TRect(TInt, TInt, TInt, TInt)
	TRect(const TPoint &, const TPoint &)
	TRect(const TPoint &, const TSize &)
	TRect(const TSize &)
IMPORT_C void	BoundingRect(const TRect &)
IMPORT_C TPoint	Center()
IMPORT_C TBool	Contains(const TPoint &)
IMPORT_C void	Grow(TInt, TInt)
IMPORT_C void	Grow(const TSize &)
IMPORT_C TInt	Height()
IMPORT_C void	Intersection(const TRect &)
IMPORT_C TBool	Intersects(const TRect &)
IMPORT_C TBool	IsEmpty()
IMPORT_C TBool	IsNormalized()
IMPORT_C void	Move(TInt, TInt)
IMPORT_C void	Move(const TPoint &)
IMPORT_C void	Normalize()
IMPORT_C void	Resize(TInt, TInt)
IMPORT_C void	Resize(const TSize &)
IMPORT_C void	SetHeight(TInt)
IMPORT_C void	SetRect(TInt, TInt, TInt, TInt)
IMPORT_C void	SetRect(const TPoint &, const TPoint &)
IMPORT_C void	SetRect(const TPoint &, const TSize &)
IMPORT_C void	SetSize(const TSize &)
IMPORT_C void	SetWidth(TInt)
IMPORT_C void	Shrink(TInt, TInt)
IMPORT_C void	Shrink(const TSize &)
IMPORT_C TSize	Size()
IMPORT_C TInt	Width()
IMPORT_C TBool	operator!=(const TRect &)
IMPORT_C TBool	operator==(const TRect &)

Detailed Description

Geometric rectangle.

The class represents a rectangle whose sides are parallel with the axes of the co-ordinate system.

The co-ordinates of the top-left and bottom-right corners are used to set the dimensions of the rectangle. The bottom right co-ordinate is outside the rectangle. Thus TRect(TPoint(2,2),TSize(4,4)) is equal to TRect(TPoint(2,2),TPoint(6,6)), and in both cases you get a 4x4 pixel rectangle on the screen.

Functions are provided to initialise and manipulate the rectangle and to extract information about it.

Member Attribute Documentation

iBr

TPoint

iBr

The x and y co-ordinates of the bottom right hand corner of the rectangle.

iTl

TPoint

iTl

The x and y co-ordinates of the top left hand corner of the rectangle.

Member Enumeration Documentation

Enum TUninitialized

Enumerator	Value	Description
EUninitialized

Constructor & Destructor Documentation

TRect ( TUninitialized )

TRect

(

TUninitialized

)

[inline]

Constructs a default rectangle.

This initialises the co-ordinates of its top left and bottom right corners to (0,0).

TRect ( )

IMPORT_C

TRect

(

)

Constructs a default rectangle.

This initialises the co-ordinates of its top left and bottom right corners to (0,0).

TRect ( TInt, TInt, TInt, TInt )

IMPORT_C	TRect	(	TInt	aAx,
			TInt	aAy,
			TInt	aBx,
			TInt	aBy
		)

Constructs the rectangle, initialising its top left and bottom right hand corners with four TInt values.

Parameters
aAx	The horizontal co-ordinate of the left hand side of the rectangle.
aAy	The vertical co-ordinate of the top of the rectangle.
aBx	The horizontal co-ordinate of the right hand side of the rectangle.
aBy	The vertical co-ordinate of the bottom of the rectangle.

TRect ( const TPoint &, const TPoint & )

IMPORT_C	TRect	(	const TPoint &	aPointA,
			const TPoint &	aPointB
		)

Constructs the rectangle with two TPoints, corresponding to its top left and bottom right hand corners.

Parameters
aPointA	The co-ordinates of the rectangle's top left hand corner.
aPointB	The co-ordinates of the rectangle's bottom right hand corner.

TRect ( const TPoint &, const TSize & )

IMPORT_C	TRect	(	const TPoint &	aPoint,
			const TSize &	aSize
		)

Constructs the rectangle with a TPoint for its top left corner, and a TSize for its width and height.

Parameters
aPoint	The rectangle's top left hand corner.
aSize	The rectangle's width and height.

TRect ( const TSize & )

IMPORT_C

TRect

(

const TSize &

aSize

)

Constructs the rectangle with a TSize.

The co-ordinates of its top left hand corner are initialised to (0,0) and its width and height are initialised to the values contained in the argument.

Parameters
aSize	The width and height of the rectangle.

Member Function Documentation

BoundingRect ( const TRect & )

IMPORT_C void

BoundingRect

(

const TRect &

aRect

)

Gets the minimal rectangle which bounds both this rectangle and the specified rectangle, and assigns it to this rectangle.

Parameters
aRect	The rectangle to use with this rectangle to get the minimal bounding rectangle.

Center ( )

IMPORT_C TPoint

Center

(

)

const

Gets the point at the centre of the rectangle.

Return Value: The point at the centre of the rectangle.

Contains ( const TPoint & )

IMPORT_C TBool

Contains

(

const TPoint &

aPoint

)

const

Tests whether a point is located within the rectangle.

Note that a point located on the top or left hand side of the rectangle is within the rectangle. A point located on the right hand side or bottom is considered to be outside the rectangle.

Parameters
aPoint	The point to be tested.

Return Value: True, if the point is within the rectangle; false, otherwise.

Grow ( TInt, TInt )

IMPORT_C void	Grow	(	TInt	aDx,
			TInt	aDy
		)

Grows the rectangle using the specified horizontal and vertical offsets.

The offset values are subtracted from the co-ordinates of its top left hand corner, and the same values are added to the co-ordinates of its bottom right hand corner. The co-ordinates of the centre of the rectangle remain unchanged. If either value is negative, the rectangle shrinks in the corresponding direction.

Parameters
aDx	The number of pixels by which to move the left and right hand sides of the rectangle. A positive value increases the width, a negative value reduces it.
aDy	The number of pixels by which to move the top and bottom of the rectangle. A positive value increases the height, a negative value reduces it.

Grow ( const TSize & )

IMPORT_C void

Grow

(

const TSize &

aSize

)

Grows a rectangle using the specified TSize offset.

The rectangle grows by twice the value of the height and width specified in the TSize. The co-ordinates of the centre of the rectangle remain unchanged. If either value is negative, the rectangle shrinks in the corresponding direction.

Parameters
aSize	The number of pixels by which to move the left and right hand sides of the rectangle (by aSize.iWidth) and the top and bottom (by aSize.iHeight).

Height ( )

IMPORT_C TInt

Height

(

)

const

Gets the height of the rectangle.

Return Value: The height of the rectangle.

Intersection ( const TRect & )

IMPORT_C void

Intersection

(

const TRect &

aRect

)

Gets the area of intersection between this rectangle and the specified rectangle, and assigns it to this rectangle.

It is usual to call TRect::Intersects() first to verify whether the two rectangles intersect. If the two rectangles do not intersect, then, on return, this rectangle is set to be empty.

Parameters
aRect	The rectangle to be used with this rectangle to get the area of intersection.

Intersects ( const TRect & )

IMPORT_C TBool

Intersects

(

const TRect &

aRect

)

const

Tests whether this rectangle overlaps with the specified rectangle.

Two rectangles overlap if any point is located within both rectangles. There is no intersection if two adjacent sides touch without overlapping, or if either rectangle is empty.

Parameters
aRect	The rectangle to compare with this rectangle for an intersection.

Return Value: True, if the two rectangles overlap; false, if there is no overlap.

IsEmpty ( )

IMPORT_C TBool

IsEmpty

(

)

const

Tests whether the rectangle is empty.

Return Value: True, if empty; false, if not.

IsNormalized ( )

IMPORT_C TBool

IsNormalized

(

)

const

Tests whether the rectangle is normalised.

A rectangle is normalised when its width and height are both zero or greater.

Return Value: True, if normalised; false, if not.

Move ( TInt, TInt )

IMPORT_C void	Move	(	TInt	aDx,
			TInt	aDy
		)

Moves the rectangle by adding an x, y offset.

The offset is added to the co-ordinates of both its top left and bottom right hand corners. The size of the rectangle is unchanged.

Parameters
aDx	The number of pixels to move the rectangle horizontally. If negative, the rectangle moves leftwards.
aDy	The number of pixels to move the rectangle vertically. If negative, the rectangle moves upwards.

Move ( const TPoint & )

IMPORT_C void

Move

(

const TPoint &

aOffset

)

Moves the rectangle by adding a TPoint offset.

The offset is added to the co-ordinates of both its top left and bottom right hand corners. The size of the rectangle is unchanged.

Parameters
aOffset	The number of pixels to move the rectangle; horizontally by aOffset.iX and vertically by aOffset.iY.

Normalize ( )

IMPORT_C void

Normalize

(

)

Ensures that the rectangle's width and height have positive values.

For example, if the rectangle's co-ordinates are such that the top is below the bottom, or the right hand side is to the left of the left hand side, normalisation swaps the co-ordinates of the top and bottom or of the left and right.

Resize ( TInt, TInt )

IMPORT_C void	Resize	(	TInt	aDx,
			TInt	aDy
		)

Resizes a rectangle by adding a horizontal and vertical offset.

The offset is added to the co-ordinates of its bottom right hand corner. If either value is negative, the rectangle shrinks in the corresponding direction. The co-ordinates of the rectangle's top left hand corner are unaffected.

Parameters
aDx	The number of pixels by which to move the right hand side of the rectangle.
aDy	The number of pixels by which to move the bottom of the rectangle.

Resize ( const TSize & )

IMPORT_C void

Resize

(

const TSize &

aSize

)

Resizes a rectangle by adding a TSize offset.

The offset is added to the co-ordinates of its bottom right hand corner. If either value in the TSize is negative, the rectangle shrinks in the corresponding direction. The co-ordinates of the rectangle's top left hand corner are unaffected.

Parameters
aSize	The number of pixels by which to move the rectangle; the right hand side by aSize.iWidth and the bottom by aSize.iHeight.

SetHeight ( TInt )

IMPORT_C void

SetHeight

(

TInt

aHeight

)

Sets the height of the rectangle.

Only the position of the bottom of the rectangle is affected.

Parameters
aHeight	The new height of the rectangle.

SetRect ( TInt, TInt, TInt, TInt )

IMPORT_C void	SetRect	(	TInt	aAx,
			TInt	aAy,
			TInt	aBx,
			TInt	aBy
		)

Sets the rectangle's position using four TInts.

Parameters
aAx	The horizontal co-ordinate of the left hand side of the rectangle.
aAy	The vertical co-ordinate of the top of the rectangle.
aBx	The horizontal co-ordinate of the right hand side of the rectangle.
aBy	The vertical co-ordinate of the bottom of the rectangle.

SetRect ( const TPoint &, const TPoint & )

IMPORT_C void	SetRect	(	const TPoint &	aPointTL,
			const TPoint &	aPointBR
		)

Sets the rectangle's position using two TPoints.

Parameters
aPointTL	The co-ordinates of the rectangle's top left hand corner.
aPointBR	The co-ordinates of the rectangle's bottom right hand corner.

SetRect ( const TPoint &, const TSize & )

IMPORT_C void	SetRect	(	const TPoint &	aPoint,
			const TSize &	aSize
		)

Sets the rectangle's position using a TPoint and a TSize.

Parameters
aPoint	The co-ordinates of the rectangle's top left hand corner.
aSize	The rectangle's width and height.

SetSize ( const TSize & )

IMPORT_C void

SetSize

(

const TSize &

aSize

)

Sets the size of the rectangle.

Only the co-ordinates of the bottom right hand corner of the rectangle are affected.

Parameters
aSize	The new width is aSize.iWidth. The new height is aSize.iHeight.

SetWidth ( TInt )

IMPORT_C void

SetWidth

(

TInt

aWidth

)

Sets the width of the rectangle.

Only the position of the rectangle's right hand side is affected.

Parameters
aWidth	The new width of the rectangle.

Shrink ( TInt, TInt )

IMPORT_C void	Shrink	(	TInt	aDx,
			TInt	aDy
		)

Shrinks a rectangle using specified horizontal and vertical offsets.

The offset values are added to the co-ordinates of its top left hand corner, and the same values are subtracted from the co-ordinates of its bottom right hand corner. The co-ordinates of the centre of the rectangle remain unchanged. If either value is negative, the rectangle expands in the corresponding direction.

Parameters
aDx	The number of pixels by which to move the left and right hand sides of the rectangle. A positive value reduces the width, a negative value increases it.
aDy	The number of pixels by which to move the top and bottom of the rectangle. A positive value reduces the height, a negative value increases it.

Shrink ( const TSize & )

IMPORT_C void

Shrink

(

const TSize &

aSize

)

Shrinks a rectangle using a specified TSize offset.

The rectangle shrinks by twice the value of the height and width specified in the TSize. The co-ordinates of the centre of the rectangle remain unchanged. If either value is negative, the rectangle expands in the corresponding direction.

Parameters
aSize	The number of pixels by which to move the left and right hand sides of the rectangle (by aSize.iWidth) and the top and bottom (by aSize.iHeight).

Size ( )

IMPORT_C TSize

Size

(

)

const

Gets the size of the rectangle.

Return Value: The size of the rectangle.

Width ( )

IMPORT_C TInt

Width

(

)

const

Gets the width of the rectangle.

Return Value: The width of the rectangle.

operator!= ( const TRect & )

IMPORT_C TBool

operator!=

(

const TRect &

aRect

)

const

Compares two rectangles for inequality.

Two rectangles are unequal if any of their co-ordinates differ.

Parameters
aRect	The rectangle to compare with this rectangle.

Return Value: True, if the rectangles do not have the same co-ordinates; false, if all co-ordinates are equal.

operator== ( const TRect & )

IMPORT_C TBool

operator==

(

const TRect &

aRect

)

const

Compares two rectangles for equality.

For two rectangles to be equal, the co-ordinates of both their top left and bottom right hand corners must be equal.

Parameters
aRect	The rectangle to compare with this rectangle.

Return Value: True, if the rectangles have the same co-ordinates; false, otherwise.