CGifScaler Class Reference

#include <gifscaler.h>

Link against: gifscaler.lib

class CGifScaler : public CBase

Inherits from

CGifScaler

Public Member Enumerations
enum	TOptions { ELowQualityQuantization, EMediumQualityQuantization, EHighQualityQuantization, EMaximumQualityQuantization }

Public Member Functions
	~CGifScaler()
IMPORT_C void	Cancel()
IMPORT_C CGifScaler *	NewL(CFbsBitmap &, TOptions)
IMPORT_C CGifScaler *	NewL(CFbsBitmap &, CFbsBitmap &, TOptions)
IMPORT_C void	Scale(TRequestStatus *, CFbsBitmap &, CPalette &, TBool)
IMPORT_C void	ThresholdScale(TRequestStatus *, CFbsBitmap &, CPalette &, TUint8, 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 GifScaler scaling and color quantization library.

Member Enumeration Documentation

Enum TOptions

TOptions is an enumeration within the namespace CGifScaler The enumeration provides a set of supported quantization levels: (EHighQualityQuantization is the default setting as it provides the best balance between quality and speed)

Enumerator	Value	Description
ELowQualityQuantization		Provides the lowest quality, but also the fastest.
EMediumQualityQuantization		Provides medium quality quantization
EHighQualityQuantization		Provides high quality quantization
EMaximumQualityQuantization		Provides the highest quality quantization, but is also the slowest.

Constructor & Destructor Documentation

~CGifScaler ( )

IMPORT_C

~CGifScaler

(

)

This is the destructor for the CGifScaler and is responsible for deallocating all resources allocated by the CGifScaler.

Member Function Documentation

Cancel ( )

IMPORT_C void

Cancel

(

)

Cancel any outstanding activity.

NewL ( CFbsBitmap &, TOptions )

IMPORT_C CGifScaler *	NewL	(	CFbsBitmap &	aSource,
			TOptions	aOptions = EHighQualityQuantization
		)	[static]

The function NewL constructs a CGifScaler. This version constructs a scaler for scaling and color quantizing only. No mask data is required in this case)

leave: KErrArgument if the source bitmap or the options are invalid.

panic: ENoSourceBitmap if the source bitmap has not been created.

Parameter	Description
aSource	The bitmap to be re-scaled.
aOptions	Scaling and color quantization options.

Returns: A pointer to a fully constructed CGifScaler

NewL ( CFbsBitmap &, CFbsBitmap &, TOptions )

IMPORT_C CGifScaler *	NewL	(	CFbsBitmap &	aSource,
			CFbsBitmap &	aSourceMask,
			TOptions	aOptions = EHighQualityQuantization
		)	[static]

The function NewL constructs a CGifScaler. This version constructs a scaler for scaling and color quantizing an image with transparency.

leave: KErrArgument if the source bitmap, source mask bitmap, or the options are invalid.

panic: ENoSourceBitmap if the source bitmap has not been created.

panic: ENoSourceMaskBitmap if the source mask bitmap has not been created.

Parameter	Description
aSource	The bitmap to be re-scaled.
aSourceMask	The mask bitmap that provides the transparency data.
aOptions	Scaling and color quantization options.

Returns: A pointer to a fully constructed CGifScaler

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

IMPORT_C void	Scale	(	TRequestStatus *	aStatus,
			CFbsBitmap &	aDestination,
			CPalette &	aPalette,
			TBool	aMaintainAspectRatio = ETrue
		)

Scale the source bitmap and mask to produce a single 8bpp bitmap and an output palette. If a mask was supplied during construction the last index in the palette will be used for transparency.

The scaling factor is based on the relative sizes of the source and target bitmaps. The operation is asynchronous. When it is complete, successfully or otherwise, the TRequestStatus aStatus is set, passing the state of the operation.

Parameter	Description
aStatus	Request status to signal when scaling is complete.
aDestination	The destination bitmap. (EColor256)
aPalette	The output palette.
aMaintainAspectRatio	ETrue - 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 - the aspect ratio need not be retained.

ThresholdScale ( TRequestStatus *, CFbsBitmap &, CPalette &, TUint8, TBool )

IMPORT_C void	ThresholdScale	(	TRequestStatus *	aStatus,
			CFbsBitmap &	aDestination,
			CPalette &	aPalette,
			TUint8	aTransparencyThreshold,
			TBool	aMaintainAspectRatio = ETrue
		)

Scale the source bitmap and mask to produce a single 8bpp bitmap and an output palette, specifying a transparency level to be used when determining whether destination pixels are transparent. If a mask was supplied during construction the last index in the palette will be used for transparency.

Parameter	Description
aStatus	Request status to signal when scaling is complete.
aDestination	The destination bitmap. (EColor256)
aPalette	The output palette.
aTransparencyThreshold	The transparency level used to determine if destination pixels are transparent.
aMaintainAspectRatio	ETrue - 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 - the aspect ratio need not be retained.