Class TEllipse

class TEllipse;

Description

Members

Defined in TEllipse:
Construct(), EComplete, EFirstSector, EInitialised, ELine, ESecondSector, Intersection(), NextStep(), Output(), SingleStep(), TEllipseStatus, iA, iASquBSqu, iASquared, iB, iBSquared, iD1, iD2, iOffset, iStatus, iX, iXAdj, iY, iYAdj

IMPORT_C void Construct(const TRect &aRect);

Description

Initialises the values of the ellipse so that it conforms to a rectangle entered as a parameter.

Parameters

const TRect &aRect the rectangle within which the ellipse is drawn

IMPORT_C TBool SingleStep(TPoint &aTopLeft, TPoint &aTopRight, TPoint &aBottomLeft, TPoint &aBottomRight);

Description

Does the next stage in producing an ellipse by taking four points (the corners of the rectangle the ellipse should fill) as parameters. Updates TEllipse status accordingly and calls Output(aTopLeft,aTopRight,aBottomLeft,aBottomRight) .

Parameters

TPoint &aTopLeft Top left corner of rectangle TPoint &aTopRight Top right corner of rectangle TPoint &aBottomLeft Bottom left corner of rectangle TPoint &aBottomRight Bottom right corner of rectangle

Return value

TBool TBool ETrue if step completed successfully.

IMPORT_C TBool NextStep(TPoint &aTopLeft, TPoint &aTopRight, TPoint &aBottomLeft, TPoint &aBottomRight);

Description

By analysing the current state of the ellipse the process is taken to the next appropriate step. If iStatus = EInitialised only one step will be taken, if the ellipse is already semi constructed then it will be taken to completion. Takes in four point parameters that defines the rectangle in order to pass to SingleStep(aTopLeft,aTopRight,aBottomLeft,aBottomRight).

Parameters

TPoint &aTopLeft Top left corner of rectangle TPoint &aTopRight Top right corner of rectangle TPoint &aBottomLeft Bottom left corner of rectangle TPoint &aBottomRight Bottom right corner of rectangle

Return value

TBool TBool ETrue if a valid rectangle is produced, else EFalse.

IMPORT_C TPoint Intersection(const TRect &aRect, const TPoint &aPoint);

Description

Constructs an ellipse from the rectangle which it is given and assesses the points position with regard to the ellipse and where they intersect.

Parameters

const TRect &aRect The rectangle within which the ellipse is drawn. const TPoint &aPoint A point to compare with the ellipse to determine if intersection occurs.

Return value

TPoint TPoint The point is set to the corner which the intersection is nearest to.

protected: IMPORT_C TBool Output(TPoint &aTopLeft, TPoint &aTopRight, TPoint &aBottomLeft, TPoint &aBottomRight);

Description

Sets the absolute points that define the ellipse as calculated using its iOffset from the origin and using the half width and half height of the rectangle iA and iB.

Parameters

TPoint &aTopLeft The absolute (x,y) position for the top left point. TPoint &aTopRight The absolute (x,y) position for the top right point. TPoint &aBottomLeft The absolute (x,y) position for the bottom left point. TPoint &aBottomRight The absolute (x,y) position for the bottom right point.

Return value

TBool TBool ETrue if a valid rectangle is produced, else EFalse. Also sets iStatus to EComplete.

TEllipseStatus

Description

Enumeration for the ellipse production life cycle

EInitialised Ellipse has been initialised but has no area EFirstSector The ellipse is drawn as two parabolas. These are in two sectors, the top and bottom half of the rectangle. The first sector means the top parabola has been produced. ESecondSector The parabola that occupies the bottom half of the rectangle has been produced. EComplete The ellipse is complete ELine The ellipse has either a height or width of two units or less and so takes the appearance of a line

protected: TEllipseStatus iStatus;

Description

protected: TInt iA;

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protected: TInt iB;

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protected: TInt64 iASquared;

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protected: TInt64 iBSquared;

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protected: TInt64 iASquBSqu;

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protected: TInt iX;

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protected: TInt iY;

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protected: TInt iXAdj;

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protected: TInt iYAdj;

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protected: TPoint iOffset;

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protected: TInt64 iD1;

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protected: TInt64 iD2;

Description