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TZoomFactor Class Reference

class TZoomFactor : public MGraphicsDeviceMap

The interface for mapping between twips and device-specific units enriched with facilities to allow zooming.

The class is recursive, because a TZoomFactor object can have a MGraphicsDeviceMap (which could itself be a TZoomFactor) in its member data. This allows a zoom factor object to contain another zoom factor object, and is used to allow objects with different zoom factors to be embedded in each other to an arbitrary depth by the application architecture.

Inherits from

TZoomFactor
- MGraphicsDeviceMap

Public Member Functions
	TZoomFactor()
	TZoomFactor(const MGraphicsDeviceMap *)
	TZoomFactor(const TZoomFactor *)
	~TZoomFactor()
IMPORT_C TInt	GetNearestFontInTwips(CFont *&, const TFontSpec &)
IMPORT_C TInt	GetNearestFontToDesignHeightInTwips(CFont *&, const TFontSpec &)
IMPORT_C TInt	GetNearestFontToMaxHeightInTwips(CFont *&, const TFontSpec &, TInt)
const MGraphicsDeviceMap *	GraphicsDeviceMap()
IMPORT_C TInt	HorizontalPixelsToTwips(TInt)
IMPORT_C TInt	HorizontalTwipsToPixels(TInt)
IMPORT_C void	ReleaseFont(CFont *)
void	SetGraphicsDeviceMap(const MGraphicsDeviceMap *)
IMPORT_C void	SetTwipToPixelMapping(const TSize &, const TSize &)
IMPORT_C void	SetZoomFactor(TInt)
IMPORT_C TInt	VerticalPixelsToTwips(TInt)
IMPORT_C TInt	VerticalTwipsToPixels(TInt)
IMPORT_C TInt	ZoomFactor()

Inherited Functions
	MGraphicsDeviceMap::MGraphicsDeviceMap()
	MGraphicsDeviceMap::PixelsToTwips(const TPoint &)const
	MGraphicsDeviceMap::PixelsToTwips(const TRect &)const
	MGraphicsDeviceMap::TwipsToPixels(const TPoint &)const
	MGraphicsDeviceMap::TwipsToPixels(const TRect &)const
	MGraphicsDeviceMap::~MGraphicsDeviceMap()

Private Attributes
const MGraphicsDeviceMap *	iDevice
TInt	iZoomFactor

Constructor & Destructor Documentation

TZoomFactor()

IMPORT_C

TZoomFactor

(

)

Constructs a default zoom factor object.

Note that a TZoomFactor object cannot be used until a CGraphicsDevice to which it is associated is specified (by SetGraphicsDeviceMap()). Therefore the other constructor is normally used for constructing TZoomFactors. The default constructor function is provided for use in TZoomFactor-derived classes.

TZoomFactor(const MGraphicsDeviceMap *)

TZoomFactor

(

const MGraphicsDeviceMap *

aDevice

)

[inline]

Constructs a zoom factor object for a specific graphics device map.

The graphics map is either directly associated with a particular graphics device itself, or is associated with a hierarchy of device maps whose root map is associated with a particular graphics device.

Parameters

const MGraphicsDeviceMap * aDevice

The graphics device map with which the zoom factor is associated.

TZoomFactor(const TZoomFactor *)

TZoomFactor

(

const TZoomFactor *

aDevice

)

[inline]

Parameters

const TZoomFactor * aDevice

~TZoomFactor()

IMPORT_C

~TZoomFactor

(

)

Destructor.

Frees resources owned by the object, prior to its destruction.

Member Functions Documentation

GetNearestFontInTwips(CFont *&, const TFontSpec &)

IMPORT_C TInt	GetNearestFontInTwips	(	CFont *&	aFont,
			const TFontSpec &	aFontSpec
		)	[virtual]

Parameters

CFont *& aFont
const TFontSpec & aFontSpec

GetNearestFontToDesignHeightInTwips(CFont *&, const TFontSpec &)

IMPORT_C TInt	GetNearestFontToDesignHeightInTwips	(	CFont *&	aFont,
			const TFontSpec &	aFontSpec
		)	[virtual]

Gets the font which is the nearest to the given font specification. Matching to design height gives no guarantees on the actual physical size of the font.

Parameters

CFont *& aFont	On return, contains a pointer to the nearest font.
const TFontSpec & aFontSpec	The specification of the font to be matched.

GetNearestFontToMaxHeightInTwips(CFont *&, const TFontSpec &, TInt)

IMPORT_C TInt	GetNearestFontToMaxHeightInTwips	(	CFont *&	aFont,
			const TFontSpec &	aFontSpec,
			TInt	aMaxHeight
		)	[virtual]

Gets the font which is the nearest to the given font specification. Matching to maximum height returns a font that will fit within the height specified.

Parameters

CFont *& aFont	On return, contains a pointer to the nearest font.
const TFontSpec & aFontSpec	The specification of the font to be matched.
TInt aMaxHeight	The maximum height within which the font must fit. This overrides the height specified in aFontSpec. If maximum height is greater than 1024 pixels, the function returns KErrTooBig. And returns KErrArgument if equals to 1 pixel.

GraphicsDeviceMap()

const MGraphicsDeviceMap *

GraphicsDeviceMap

(

)

const [inline]

Gets the graphics device map of this zoom factor object.

HorizontalPixelsToTwips(TInt)

IMPORT_C TInt

HorizontalPixelsToTwips

(

TInt

aPixelWidth

)

const [virtual]

Converts a horizontal dimension from pixels to twips on the graphics device.

This function implements the pure virtual function defined in MGraphicsDeviceMap::HorizontalPixelsToTwips()

Parameters

TInt aPixelWidth

HorizontalTwipsToPixels(TInt)

IMPORT_C TInt

HorizontalTwipsToPixels

(

TInt

aTwipWidth

)

const [virtual]

Converts a horizontal dimension from twips to pixels on the graphics device.

This function implements the pure virtual function defined in MGraphicsDeviceMap::HorizontalTwipsToPixels()

Parameters

TInt aTwipWidth

ReleaseFont(CFont *)

IMPORT_C void

ReleaseFont

(

CFont *

aFont

)

[virtual]

Releases the specified font.

This function implements the pure virtual function defined in MGraphicsDeviceMap::ReleaseFont()

Parameters

CFont * aFont

A pointer to the font to be released.

SetGraphicsDeviceMap(const MGraphicsDeviceMap *)

void

SetGraphicsDeviceMap

(

const MGraphicsDeviceMap *

aDevice

)

[inline]

Sets the graphics device map for this zoom factor object.

Parameters

const MGraphicsDeviceMap * aDevice

The graphics device map for this TZoomFactor.

SetTwipToPixelMapping(const TSize &, const TSize &)

IMPORT_C void	SetTwipToPixelMapping	(	const TSize &	aSizeInPixels,
			const TSize &	aSizeInTwips
		)

Sets the twips to pixels mapping for the graphics device with which the zoom factor is associated.

This setting is used by all the twips to pixels and pixels to twips conversion functions.

Parameters

const TSize & aSizeInPixels	The size of the graphics device area in pixels.
const TSize & aSizeInTwips	The size of the graphics device area in twips.

SetZoomFactor(TInt)

IMPORT_C void

SetZoomFactor

(

TInt

aZoomFactor

)

Sets the zoom factor.

Parameters

TInt aZoomFactor

The desired zoom factor.

VerticalPixelsToTwips(TInt)

IMPORT_C TInt

VerticalPixelsToTwips

(

TInt

aPixelHeight

)

const [virtual]

Converts a vertical dimension from pixels to twips on the graphics device.

This function implements the pure virtual function defined in MGraphicsDeviceMap::VerticalPixelsToTwips()

Parameters

TInt aPixelHeight

VerticalTwipsToPixels(TInt)

IMPORT_C TInt

VerticalTwipsToPixels

(

TInt

aTwipHeight

)

const [virtual]

Converts a vertical dimension from twips to pixels on the graphics device.

This function implements the pure virtual function defined in MGraphicsDeviceMap::VerticalTwipsToPixels()

Parameters

TInt aTwipHeight

ZoomFactor()

IMPORT_C TInt

ZoomFactor

(

)

const

Gets the zoom factor.

Member Data Documentation

const MGraphicsDeviceMap * iDevice

const MGraphicsDeviceMap *

iDevice

[private]

TInt iZoomFactor

TInt

iZoomFactor

[private]