Class TRect

class TRect;

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.

Members

Defined in TRect:

• BoundingRect(const TRect &)Gets the minimal rectangle which bounds both this rectangle and the specified re...
• Center()constGets the point at the centre of the rectangle.
• Contains(const TPoint &)constTests whether a point is located within the rectangle.
• EUninitialized
• Grow(TInt,TInt)Grows the rectangle using the specified horizontal and vertical offsets.
• Grow(const TSize &)Grows a rectangle using the specified TSize offset.
• Height()constGets the height of the rectangle.
• Intersection(const TRect &)Gets the area of intersection between this rectangle and the specified rectangle...
• Intersects(const TRect &)constTests whether this rectangle overlaps with the specified rectangle.
• IsEmpty()constTests whether the rectangle is empty.
• IsNormalized()constTests whether the rectangle is normalised.
• Move(TInt,TInt)Moves the rectangle by adding an x, y offset.
• Move(const TPoint &)Moves the rectangle by adding a TPoint offset.
• Normalize()Ensures that the rectangle's width and height have positive values.
• Resize(TInt,TInt)Resizes a rectangle by adding a horizontal and vertical offset.
• Resize(const TSize &)Resizes a rectangle by adding a TSize offset.
• SetHeight(TInt)Sets the height of the rectangle.
• SetRect(TInt,TInt,TInt,TInt)Sets the rectangle's position using four TInts.
• SetRect(const TPoint &,const TPoint &)Sets the rectangle's position using two TPoints.
• SetRect(const TPoint &,const TSize &)Sets the rectangle's position using a TPoint and a TSize.
• SetSize(const TSize &)Sets the size of the rectangle.
• SetWidth(TInt)Sets the width of the rectangle.
• Shrink(TInt,TInt)Shrinks a rectangle using specified horizontal and vertical offsets.
• Shrink(const TSize &)Shrinks a rectangle using a specified TSize offset.
• Size()constGets the size of the rectangle.
• TRect()Constructs a default rectangle.
• TRect(TInt,TInt,TInt,TInt)Constructs the rectangle, initialising its top left and bottom right hand corner...
• TRect(TUninitialized)Constructs a default rectangle.
• TRect(const TPoint &,const TPoint &)Constructs the rectangle with two TPoints, corresponding to its top left and bot...
• TRect(const TPoint &,const TSize &)Constructs the rectangle with a TPoint for its top left corner, and a TSize for ...
• TRect(const TSize &)Constructs the rectangle with a TSize.
• TUninitialized
• Width()constGets the width of the rectangle.
• iBrThe x and y co-ordinates of the bottom right hand corner of the rectangle.
• iTlThe x and y co-ordinates of the top left hand corner of the rectangle.
• operator!=(const TRect &)constCompares two rectangles for inequality.
• operator==(const TRect &)constCompares two rectangles for equality.

inline TRect(TUninitialized);

Description

Constructs a default rectangle.

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

Parameters

IMPORT_C TRect();

Description

Constructs a default rectangle.

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

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

Description

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

Parameters

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

Description

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

Parameters

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

Description

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

Parameters

IMPORT_C TRect(const TSize &aSize);

Description

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

IMPORT_C TBool operator==(const TRect &aRect) const;

Description

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

Return value

IMPORT_C TBool operator!=(const TRect &aRect) const;

Description

Compares two rectangles for inequality.

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

Parameters

Return value

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

Description

Sets the rectangle's position using four TInts.

Parameters

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

Description

Sets the rectangle's position using two TPoints.

Parameters

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

Description

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

Parameters

IMPORT_C void Move(TInt aDx, TInt aDy);

Description

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

IMPORT_C void Move(const TPoint &aOffset);

Description

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

IMPORT_C void Resize(TInt aDx, TInt aDy);

Description

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

IMPORT_C void Resize(const TSize &aSize);

Description

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

IMPORT_C void Shrink(TInt aDx, TInt aDy);

Description

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

IMPORT_C void Shrink(const TSize &aSize);

Description

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

IMPORT_C void Grow(TInt aDx, TInt aDy);

Description

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

IMPORT_C void Grow(const TSize &aSize);

Description

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

IMPORT_C void BoundingRect(const TRect &aRect);

Description

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

Parameters

IMPORT_C TBool IsEmpty() const;

Description

Tests whether the rectangle is empty.

Return value

IMPORT_C TBool Intersects(const TRect &aRect) const;

Description

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

Return value

IMPORT_C void Intersection(const TRect &aRect);

Description

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(const TRect &)const 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

See also:

• TRect::Intersects(const TRect &)constTests whether this rectangle overlaps with the specified rectangle.

IMPORT_C void Normalize();

Description

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.

IMPORT_C TBool Contains(const TPoint &aPoint) const;

Description

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

Return value

IMPORT_C TSize Size() const;

Description

Gets the size of the rectangle.

Return value

IMPORT_C TInt Width() const;

Description

Gets the width of the rectangle.

Return value

IMPORT_C TInt Height() const;

Description

Gets the height of the rectangle.

Return value

IMPORT_C TBool IsNormalized() const;

Description

Tests whether the rectangle is normalised.

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

Return value

IMPORT_C TPoint Center() const;

Description

Gets the point at the centre of the rectangle.

Return value

IMPORT_C void SetSize(const TSize &aSize);

Description

Sets the size of the rectangle.

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

Parameters

IMPORT_C void SetWidth(TInt aWidth);

Description

Sets the width of the rectangle.

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

Parameters

IMPORT_C void SetHeight(TInt aHeight);

Description

Sets the height of the rectangle.

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

Parameters

TUninitialized

Description

TPoint iTl;

Description

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

TPoint iBr;

Description

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