CPolygonFiller Class Reference

#include <bitstd.h>

class CPolygonFiller : public CBase

Inherits from

CPolygonFiller
- CBase

Public Member Enumerations
enum	TUsage { EGetAllPixelRunsSequentially, EGetPixelRunsSequentiallyForSpecifiedScanLines }

Public Member Functions
	CPolygonFiller()
	~CPolygonFiller()
IMPORT_C void	Construct(const CArrayFix< TPoint > *, CGraphicsContext::TFillRule, TUsage)
IMPORT_C void	Construct(const TPoint *, TInt, CGraphicsContext::TFillRule, TUsage)
IMPORT_C void	GetNextPixelRun(TBool &, TInt &, TInt &, TInt &)
IMPORT_C void	GetNextPixelRunOnSpecifiedScanLine(TBool &, TInt, TInt &, TInt &)
IMPORT_C void	Reset()

Inherited Functions
	CBase::CBase()
	CBase::Delete(CBase *)
	CBase::Extension_(TUint,TAny &,TAny )
	CBase::operator new(TUint)
	CBase::operator new(TUint,TAny *)
	CBase::operator new(TUint,TLeave)
	CBase::operator new(TUint,TLeave,TUint)
	CBase::operator new(TUint,TUint)
	CBase::~CBase()

Member Enumeration Documentation

Enum TUsage

Describes how pixels are to be displayed in the polygon. aUsage should be select to one of these values before CPolygonFiller::Construct is used.

Enumerator	Value	Description
EGetAllPixelRunsSequentially		A request for all pixel runs in sequential order
EGetPixelRunsSequentiallyForSpecifiedScanLines		A request for all pixel runs in sequential order but only for specified lines.

Constructor & Destructor Documentation

CPolygonFiller ( )

IMPORT_C

CPolygonFiller

(

)

Constructor which initializes all member data to zero, EFalse or null for TInt, TBool pointers respectively.

~CPolygonFiller ( )

IMPORT_C

~CPolygonFiller

(

)

Destructor calls reset on the polygon.

Member Function Documentation

Construct ( const CArrayFix< TPoint > *, CGraphicsContext::TFillRule, TUsage )

IMPORT_C void	Construct	(	const CArrayFix< TPoint > *	aPointArray,
			CGraphicsContext::TFillRule	aFillRule,
			TUsage	aUsage = EGetAllPixelRunsSequentially
		)

An overloaded version of Construct which allows the list of points to be passed in as a point array. Exactly the same behaviour and structure as above. This should not fail. This method does not require the number of nodes to be given as a parameter.

Parameters
aFillRule	How filling should be achieved, as described by a CGraphicsContext::TFillRule object.
aUsage	How the polygon should be used.

Construct ( const TPoint *, TInt, CGraphicsContext::TFillRule, TUsage )

IMPORT_C void	Construct	(	const TPoint *	aPointList,
			TInt	aNumPoints,
			CGraphicsContext::TFillRule	aFillRule,
			TUsage	aUsage = EGetAllPixelRunsSequentially
		)

Takes a list of points to be the points for the new polygon and sets the number of points in the shape. After this has been done it transfers the task to Construct(aFillRule,aUsage). This should not fail.

Parameters
aPointList	A list of points for the polygon.
aNumPoints	The number of points in the list.
aFillRule	How filling should be achieved, as described by a CGraphicsContext::TFillRule object.
aUsage	How the polygon should be used, see TUsage enumeration.

GetNextPixelRun ( TBool &, TInt &, TInt &, TInt & )

IMPORT_C void	GetNextPixelRun	(	TBool &	aExists,
			TInt &	aScanLine,
			TInt &	aStart,
			TInt &	aEnd
		)

Method is used to calculate the locations of vertex interactions between the polygon and scan lines. An initial scan line is required. It calculates the start and end positions on the line. The method can use either the fast or slow polygon algorithm depending upon the state of aUsage. Polygon filling is also addressed by this method.

Parameters
aExists	Will be set to false if a polygon with no vertexes is passed in, otherwise ETrue on return.
aStart	The position on the scan line to start the run, on returned.
aEnd	The position on the scan line to end the run, returned.

GetNextPixelRunOnSpecifiedScanLine ( TBool &, TInt, TInt &, TInt & )

IMPORT_C void	GetNextPixelRunOnSpecifiedScanLine	(	TBool &	aExists,
			TInt	aScanLine,
			TInt &	aStart,
			TInt &	aEnd
		)

Similar to GetNextPixelRun(aExists, aScanLine, aStart, aEnd) this method is used to draw the relevant vertex intersections for a polygon but only for an individual specified scan line. The method can use either the fast or slow polygon algorithm depending upon the state of aUsage.

Parameters
aExists	Will be set to false if the line does not pass through the polygon or if a polygon with no vertices is specified, otherwise ETrue on return.
aStart	The position on the scan line to start the run, on returned.
aEnd	The position on the scan line to end the run, returned.

Reset ( )

IMPORT_C void

Reset

(

)

Frees any data held in the polygons lists of all edges, vertexs and scan lines and sets these values to NULL. It also has the feature of setting iUseFastAlgorithm = EFalse.