CBitmapScaler Class Reference

#include <bitmaptransforms.h>

Link against: bitmaptransforms.lib

class CBitmapScaler : public CBase

Inherits from

CBitmapScaler
- CBase

Public Member Enumerations
enum	TQualityAlgorithm { EMinimumQuality, EMediumQuality, EMaximumQuality }

Public Member Functions
	~CBitmapScaler()
IMPORT_C void	Cancel()
IMPORT_C TInt	CustomCommand(TUid, TAny *)
TInt	DisablePostProcessing(TBool)
IMPORT_C CBitmapScaler *	NewL()
IMPORT_C void	Scale(TRequestStatus *, CFbsBitmap &, CFbsBitmap &, TBool)
IMPORT_C void	Scale(TRequestStatus *, CFbsBitmap &, const TSize &, TBool)
TInt	SetQualityAlgorithm(TQualityAlgorithm)
TInt	UseLowMemoryAlgorithm(TBool)

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()

Detailed Description

The public API for clients to call the BitmapTransforms Library bitmap scaling.

Member Enumeration Documentation

Enum TQualityAlgorithm

An enumeration to specify the level of quality algorithm.

Enumerator	Value	Description
EMinimumQuality		Fastest/lowest quality
EMediumQuality		Middle range speed/middle range quality
EMaximumQuality		Slowest/highest quality

Constructor & Destructor Documentation

~CBitmapScaler ( )

IMPORT_C

~CBitmapScaler

(

)

This is the destructor for the CBitmapScaler and is responsible for deallocating all resources alloctaed by the CBitmapScaler.

Member Function Documentation

Cancel ( )

IMPORT_C void

Cancel

(

)

Cancel any outstanding activity.

CustomCommand ( TUid, TAny * )

IMPORT_C TInt	CustomCommand	(	TUid	aUid,
			TAny *	aParam
		)

Provides custom command capabilties on CBitmapScaler. The command is dispatched on aUid and if the command is not known KErrNotSupported will be returned. This function is synchronous.

The Default implementation will support one command to enable and disable post processing on the scale operation The uid of this command is published in the header file. Changes to the status of Post Processing Enabled will become effective only after an exising scaling operation has completed.

Pre-condition: When a command requires parameters aParam is not NULL.

Parameters
aUid	The ID of the command.
aParam	The command specific information.

DisablePostProcessing ( TBool )

TInt

DisablePostProcessing

(

TBool

aState

)

[inline]

SetPostProcessing

Parameters
aState	a boolean flag which if true will set post processing on (Note by defualt the scaler has post processing on)

NewL ( )

IMPORT_C CBitmapScaler *

NewL

(

)

[static]

Constructs a CBitmapScaler object.

Return Value: A pointer to a CBitmapScaler object.

Scale ( TRequestStatus *, CFbsBitmap &, CFbsBitmap &, TBool )

IMPORT_C void	Scale	(	TRequestStatus *	aRequestStatus,
			CFbsBitmap &	aSrcBitmap,
			CFbsBitmap &	aTgtBitmap,
			TBool	aMaintainAspectRatio = ETrue
		)

Begins the bitmap re-scaling operation.

The scaling factor is based on the relative sizes of the source and target bitmaps. The operation is asynchronous. KErrOverFlow status is set if the sizes of input bitmaps are too large for the algorithm to handle.

Post-condition: The result of the operation is pointed to by aRequestStatus.

Parameters
aRequestStatus	On return, contains a pointer to the completion status of the rescale of the bitmap.
aSrcBitmap	The bitmap to be re-scaled.
aTgtBitmap	The target location for the re-scaled bitmap.
aMaintainAspectRatio	A boolean indicating if the aspect ratio is maintained. ETrue means the aspect ratio is retained; this is the default. The same scaling factor is applied in both the horizontal and vertical directions. This is the smaller of the horizontal scaling factor and the vertical scaling factor. EFalse means the aspect ratio need not be retained.

Scale ( TRequestStatus *, CFbsBitmap &, const TSize &, TBool )

IMPORT_C void	Scale	(	TRequestStatus *	aRequestStatus,
			CFbsBitmap &	aBitmap,
			const TSize &	aDestinationSize,
			TBool	aMaintainAspectRatio = ETrue
		)

Begins the bitmap re-scaling operation.

The scaling factor is based on the relative value of the source bitmap size and the explicitly supplied size. The operation is asynchronous. When it is complete, successfully or otherwise, the TRequestStatus is set, passing the state of the operation. KErrOverFlow status is set if the sizes of input bitmaps are too large for the algorithm to handle.

Parameters
aRequestStatus	On return, contains a pointer to the completion status of the rescale of the bitmap.
aBitmap	The bitmap to be re-scaled. This reference is also the target location for the re-scaled bitmap.
aDestinationSize	The requested target size for the re-scaled bitmap.
aMaintainAspectRatio	A boolean indicating if the aspect ratio is maintained. ETrue means the aspect ratio is retained; this is the default. The same scaling factor is applied in both the horizontal and vertical directions. This is the smaller of the horizontal scaling factor and the vertical scaling factor. EFalse means the aspect ratio need not be retained.