Class TBitmapUtil

class TBitmapUtil;

Description

Provides fast read/write access to the image data of a bitmap.

Functionality includes getting and setting the individual pixels of a bitmap. Common to this is the concept of the current pixel position. This is held as member data and is changed by using various efficient functions. For example, incrementing the position's x- or y co-ordinate is much quicker than setting a completely new position. This efficiency issue is important as these functions are used as part of the frequently used blitting DDA used for creating stretched or compressed versions of bitmaps.

Note that you should always ensure each Begin() is matched by an End() call when using this class.

Note also that all display modes including EColor16M are supported, but the TDisplayMode values ERgb and ENone are not considered to be display modes.

Members

Defined in TBitmapUtil:
Begin(), Begin(), DecXPos(), DecYPos(), End(), GetPixel(), IncXPos(), IncYPos(), SetPixel(), SetPixel(), SetPos(), TBitmapUtil()

IMPORT_C TBitmapUtil(CFbsBitmap *aBitmap);

Description

Constructs a TBitmapUtil object for the specified bitmap.

Parameters

CFbsBitmap *aBitmap The bitmap on which this TBitmapUtil will operate.

IMPORT_C void Begin(const TPoint &aPosition);

Description

Sets the current pixel position to the specified position and prepares the bitmap for access.

This function must be called before using any of the other functions provided by this class, otherwise damage to data may occur. It must also be matched by a subsequent call to End().

Parameters

const TPoint &aPosition The position to which the current pixel position should be set.

Panic codes

FBCLI 10 The bitmap's display mode is ERgb or ENone.

IMPORT_C void Begin(const TPoint &aPosition, const TBitmapUtil &aUtil);

Description

Sets the current pixel position to the specified position and prepares the bitmap for access.

This function is deprecated. Use the other overload, Begin(const TPoint&).

Parameters

const TPoint &aPosition The position to which the current pixel position should be set. const TBitmapUtil &aUtil Not used.

Panic codes

FBCLI 10 The bitmap's display mode is ERgb or ENone.

IMPORT_C void End();

Description

Undoes the preparation of the bitmap carried out by Begin().

There must be exactly one call to End() for each previous call to Begin() for a given TBitmapUtil object.

IMPORT_C TUint32 GetPixel() const;

Description

Gets the value of the pixel at the current pixel position.

In normal usage, the value returned will immediately be used as the parameter to a call to SetPixel(). To remove the overhead of constructing a TRgb, the function uses a TUint32 rather than a TRgb to hold an RGB value.

Return value

TUint32 The value of the pixel at the current pixel position.

IMPORT_C void SetPixel(TUint32 aValue);

Description

Sets the value of the pixel at the current pixel position.

To remove the overhead of constructing a TRgb, the function uses a TUint32 rather than a TRgb to hold an RGB value.

Parameters

TUint32 aValue The value to which the pixel at the current pixel position is to be set.

IMPORT_C void SetPixel(const TBitmapUtil &aSource);

Description

Sets the value of the pixel at the current pixel position to that returned by aSource.GetPixel().

Parameters

const TBitmapUtil &aSource The TBitmapUtil of the source bitmap, whose pixel value is used to set the pixel at the current pixel position.

IMPORT_C void SetPos(const TPoint &aPosition);

Description

Sets a new current pixel position.

Parameters

const TPoint &aPosition The new current pixel position.

IMPORT_C void DecXPos();

Description

Decrements the x co-ordinate of the current pixel position.

IMPORT_C void DecYPos();

Description

Decrements the y co-ordinate of the current pixel position.

IMPORT_C void IncXPos();

Description

Increments the x co-ordinate of the current pixel position.

IMPORT_C void IncYPos();

Description

Increments the y co-ordinate of the current pixel position.