Class CBitmapDevice

CBitmapDevice

Support

Supported from 5.0

Description

Defines an interface for the capabilities and attributes of a bitmapped graphics device.

Derivation

CBase Base class for all classes to be instantiated on the heap CBitmapDevice Defines an interface for the capabilities and attributes of a bitmapped graphics device CGraphicsDevice Specifies the interface for concrete device classes MGraphicsDeviceMap Interface class for mapping between twips and device-specific units (pixels)

Defined in CBitmapDevice:
AddFile(), CreateBitmapContext(), FontHeightInPixels(), GetNearestFontInPixels(), GetPixel(), GetScanLine(), RemoveFile()

Inherited from CBase:
operator new()

Inherited from CGraphicsDevice:
CreateContext(), DisplayMode(), FontHeightInTwips(), GetPalette(), NumTypefaces(), PaletteAttributes(), SetPalette(), SizeInPixels(), SizeInTwips(), TypefaceSupport()

Inherited from MGraphicsDeviceMap:
GetNearestFontInTwips(), HorizontalPixelsToTwips(), HorizontalTwipsToPixels(), PixelsToTwips(), ReleaseFont(), TwipsToPixels(), VerticalPixelsToTwips(), VerticalTwipsToPixels()

TInt CreateBitmapContext(CBitmapContext*& aGC);

Description

Creates a bitmap context for this bitmap device.

Parameters

CBitmapContext*& aGC On return, holds a pointer to the created bitmap context.

Return value

TInt KErrNone, if successful; otherwise, another of the system-wide error codes.

virtual void GetPixel(TRgb& aColor,const TPoint& aPixel) const=0;

Description

Gets the RGB colour of an individual pixel on a bitmapped graphics device.

This pure virtual function is implemented in derived classes.

Parameters

TRgb& aColor On return, should contain the RGB colour of the pixel. const TPoint& aPixel The (x,y) co-ordinates of the pixel. The top left pixel is (0,0).

virtual void GetScanLine(TDes8& aBuf,const TPoint& aStartPixel,TInt aLength,TDisplayMode aDispMode) const=0;

Description

Copies a scanline into a buffer.

The pixels are converted from the display mode format on the bitmapped graphics device to the format of the specified device display mode.

By specifying the start pixel and the number of pixels, either the whole or a portion of a bitmapped graphics device pixel row may be copied.

This pure virtual function is implemented in derived classes.

Parameters

TDes8& aBuf An 8 bit modifiable descriptor buffer into which pixels are copied; it must be sufficiently large to store all the scanline pixels. const TPoint& aStartPixel The (x,y) co-ordinates of the first pixel of the bitmap scanline to be put into the buffer. TInt aLength The number of pixels to put into the buffer. TDisplayMode aDispMode The display mode into which to convert the pixels.

virtual TInt AddFile(const TDesC& aName,TInt& aId)=0;

Description

Adds a font file to the device’s font store.

This pure virtual function is implemented in derived classes.

Parameters

const TDesC& aName The name of the font file. TInt& aId On return, contains an ID for the font file.

Return value

TInt KErrNone, if successful; otherwise, another of the system-wide error codes.

virtual void RemoveFile(TInt aId=0)=0;

Description

Removes a font file from the font store.

This pure virtual function is implemented in derived classes.

Parameters

TInt aId=0 The ID of the font file to be removed. The default is 0.

virtual TInt FontHeightInPixels(TInt aTypefaceIndex,TInt aHeightIndex) const=0;

Description

Gets the height, in pixels, of the specified typeface at one of its defined heights.

The typeface is identified by by an index. For a given typeface, there are a discrete number of heights; the specific height is also identified by an index.

The value returned is rounded up or down to the nearest font height in pixels.

This pure virtual function is implemented in derived classes.

Parameters

TInt aTypefaceIndex A typeface index number, in the range: 0 to (NumTypefaces() - 1). TInt aHeightIndex A font height index number, in the range: 0 to (iNumHeights - 1) where iNumHeights is a public data member of the TTypefaceSupport object returned by TypefaceSupport().

Return value

TInt The height of the font, in pixels.

See also:

• TTypefaceSupport
• CGraphicsDevice::NumTypefaces()
• CGraphicsDevice::TypefaceSupport()

virtual TInt GetNearestFontInPixels(CFont*& aFont,const TFontSpec& aFontSpec)=0;

Description

Gets the nearest font to that specified for use by a bitmapped graphics device.

The font and bitmap server returns a pointer to the nearest matching font from those available.

This pure virtual function is implemented in derived classes.

Parameters

CFont*& aFont On return, the pointer is set to point to the device font which most closely approximates to the required font specification. const TFontSpec& aFontSpec An absolute font specification.

Return value

TInt KErrNone, if successful; otherwise, another of the system-wide error codes.