MGraphicsDeviceMap Class Reference

#include <gdi.h>

Link against: gdi.lib

class MGraphicsDeviceMap

Public Member Functions
	MGraphicsDeviceMap()
virtual	~MGraphicsDeviceMap()
pure virtual TInt	GetNearestFontInTwips(CFont *&, const TFontSpec &)
virtual TInt	GetNearestFontToDesignHeightInTwips(CFont *&, const TFontSpec &)
virtual TInt	GetNearestFontToMaxHeightInTwips(CFont *&, const TFontSpec &, TInt)
pure virtual TInt	HorizontalPixelsToTwips(TInt)
pure virtual TInt	HorizontalTwipsToPixels(TInt)
IMPORT_C TPoint	PixelsToTwips(const TPoint &)
IMPORT_C TRect	PixelsToTwips(const TRect &)
pure virtual void	ReleaseFont(CFont *)
IMPORT_C TPoint	TwipsToPixels(const TPoint &)
IMPORT_C TRect	TwipsToPixels(const TRect &)
pure virtual TInt	VerticalPixelsToTwips(TInt)
pure virtual TInt	VerticalTwipsToPixels(TInt)

Detailed Description

Interface class for mapping between twips and device-specific units (pixels).

TZoomFactor is derived from MGraphicsDeviceMap.

Constructor & Destructor Documentation

MGraphicsDeviceMap ( )

IMPORT_C

MGraphicsDeviceMap

(

)

Default constructor.

~MGraphicsDeviceMap ( )

IMPORT_C

~MGraphicsDeviceMap

(

)

[virtual]

Destructor.

Member Function Documentation

GetNearestFontInTwips ( CFont *&, const TFontSpec & )

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

Gets the font which is the nearest to the given font specification.

When the font is no longer needed, call ReleaseFont().

Note that this deprecated function is replaced by the new GetNearestFontToDesignHeightInTwips() yielding (virtually) the same result. However clients are strongly encouraged to use the new GetNearestFontToMaxHeightInTwips() function instead. This will guarantee that every character within any given text string will fit within the given amount of twips, whereas the design height is an aesthetic unit decided by the font designer without strict physical meaning, which may result in cropped characters.

DeprecatedUse GetNearestFontToDesignHeightInTwips

Parameters
aFont	On return, contains a pointer to the nearest font.
aFontSpec	The specification of the font to be matched.

Return Value: KErrNone if successful; a system-wide error code otherwise.

GetNearestFontToDesignHeightInTwips ( CFont *&, const TFontSpec & )

TInt	GetNearestFontToDesignHeightInTwips	(	CFont *&	,
			const TFontSpec &
		)	[inline, virtual]

Gets the font which is the nearest to the given font specification.

When the font is no longer needed, call ReleaseFont().

This new function replaces the deprecated GetNearestFontInTwips() yielding (virtually) the same result. However clients are strongly encouraged to use the new GetNearestFontToMaxHeightInTwips() function instead. This will guarantee that every character within any given text string will fit within the given amount of twips, whereas the design height is an aesthetic unit decided by the font designer without strict physical meaning, which may result in cropped characters.

Return Value: KErrNone if successful; a system-wide error code otherwise.

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

TInt	GetNearestFontToMaxHeightInTwips	(	CFont *&	,
			const TFontSpec &	,
			TInt
		)	[inline, virtual]

Gets the font which is the nearest to the given font specification.

When the font is no longer needed, call ReleaseFont().

The font and bitmap server returns a pointer to the nearest matching font from those available. Matches to max height of font - this does its best to return a font that will fit within the maximum height specified (but note that variations due to hinting algorithms may rarely result in this height being exceeded by up to one pixel). Problems can also be encountered with bitmap fonts where the typeface exists but doesn't have a font small enough.

Return Value: KErrNone if successful; a system-wide error code otherwise.

HorizontalPixelsToTwips ( TInt )

TInt

HorizontalPixelsToTwips

(

TInt

aPixels

)

const [pure virtual]

Converts a horizontal dimension from pixels to twips.

An implementation is supplied by a derived class.

Parameters
aPixels	A horizontal dimension of a device in pixels.

Return Value: A horizontal dimension of a device in twips.

HorizontalTwipsToPixels ( TInt )

TInt

HorizontalTwipsToPixels

(

TInt

aTwips

)

const [pure virtual]

Converts a horizontal dimension from twips to pixels.

An implementation is supplied by a derived class.

Parameters
aTwips	A horizontal dimension of a device in twips.

Return Value: A horizontal dimension of a device in pixels.

PixelsToTwips ( const TPoint & )

IMPORT_C TPoint

PixelsToTwips

(

const TPoint &

aPixelPoint

)

const

Converts a point in pixels to a point in twips.

Parameters
aPixelPoint	A point on the graphics device in pixels.

Return Value: A point on the graphics device in twips.

PixelsToTwips ( const TRect & )

IMPORT_C TRect

PixelsToTwips

(

const TRect &

aPixelRect

)

const

Converts a rectangle in pixels to a rectangle in twips.

Parameters
aPixelRect	A rectangle on the graphics device in pixels.

Return Value: A rectangle on the graphics device in twips.

ReleaseFont ( CFont * )

void

ReleaseFont

(

CFont *

aFont

)

[pure virtual]

Releases the specified font.

It is used to indicate that the specified font is no longer needed for use by the device map. As fonts can be shared between applications, this function does not delete the copy of the font from RAM unless the font was only being used by this particular device map.

An implementation is supplied by a derived class.

Parameters
aFont	A pointer to the font to be released.

TwipsToPixels ( const TPoint & )

IMPORT_C TPoint

TwipsToPixels

(

const TPoint &

aTwipPoint

)

const

Converts a point in twips to a point in pixels.

Parameters
aTwipPoint	A point on the graphics device in twips.

Return Value: A point on the graphics device in pixels.

TwipsToPixels ( const TRect & )

IMPORT_C TRect

TwipsToPixels

(

const TRect &

aTwipRect

)

const

Converts a rectangle in twips to a rectangle in pixels.

Parameters
aTwipRect	A rectangle on the graphics device in twips

Return Value: A rectangle on the graphics device in pixels.

VerticalPixelsToTwips ( TInt )

TInt

VerticalPixelsToTwips

(

TInt

aPixels

)

const [pure virtual]

Converts a vertical dimension from pixels to twips.

An implementation is supplied by a derived class.

Parameters
aPixels	A vertical dimension of a device in pixels.

Return Value: A vertical dimension of a device in twips.

VerticalTwipsToPixels ( TInt )

TInt

VerticalTwipsToPixels

(

TInt

aTwips

)

const [pure virtual]

Converts a vertical dimension from twips to pixels.

An implementation is supplied by a derived class.

Parameters
aTwips	A vertical dimension of a device in twips.

Return Value: A vertical dimension of a device in pixels.