FreeType-2.8.1 API Reference

Bitmap Handling

Synopsis

FT_Bitmap_InitFT_Bitmap_EmboldenFT_GlyphSlot_Own_Bitmap
FT_Bitmap_CopyFT_Bitmap_ConvertFT_Bitmap_Done

This section contains functions for handling FT_Bitmap objects. Note that none of the functions changes the bitmap's ‘flow’ (as indicated by the sign of the ‘pitch’ field in ‘FT_Bitmap’).

FT_Bitmap_Init

Defined in FT_BITMAP_H (freetype/ftbitmap.h).

  FT_EXPORT( void )
  FT_Bitmap_Init( FT_Bitmap  *abitmap );


  /* deprecated */
  FT_EXPORT( void )
  FT_Bitmap_New( FT_Bitmap  *abitmap );

Initialize a pointer to an FT_Bitmap structure.

inout

abitmap

A pointer to the bitmap structure.

note

A deprecated name for the same function is ‘FT_Bitmap_New’.


FT_Bitmap_Copy

Defined in FT_BITMAP_H (freetype/ftbitmap.h).

  FT_EXPORT( FT_Error )
  FT_Bitmap_Copy( FT_Library        library,
                  const FT_Bitmap  *source,
                  FT_Bitmap        *target);

Copy a bitmap into another one.

input

library

A handle to a library object.

source

A handle to the source bitmap.

output

target

A handle to the target bitmap.

return

FreeType error code. 0 means success.


FT_Bitmap_Embolden

Defined in FT_BITMAP_H (freetype/ftbitmap.h).

  FT_EXPORT( FT_Error )
  FT_Bitmap_Embolden( FT_Library  library,
                      FT_Bitmap*  bitmap,
                      FT_Pos      xStrength,
                      FT_Pos      yStrength );

Embolden a bitmap. The new bitmap will be about ‘xStrength’ pixels wider and ‘yStrength’ pixels higher. The left and bottom borders are kept unchanged.

input

library

A handle to a library object.

xStrength

How strong the glyph is emboldened horizontally. Expressed in 26.6 pixel format.

yStrength

How strong the glyph is emboldened vertically. Expressed in 26.6 pixel format.

inout

bitmap

A handle to the target bitmap.

return

FreeType error code. 0 means success.

note

The current implementation restricts ‘xStrength’ to be less than or equal to 8 if bitmap is of pixel_mode FT_PIXEL_MODE_MONO.

If you want to embolden the bitmap owned by a FT_GlyphSlotRec, you should call FT_GlyphSlot_Own_Bitmap on the slot first.

Bitmaps in FT_PIXEL_MODE_GRAY2 and FT_PIXEL_MODE_GRAY@ format are converted to FT_PIXEL_MODE_GRAY format (i.e., 8bpp).


FT_Bitmap_Convert

Defined in FT_BITMAP_H (freetype/ftbitmap.h).

  FT_EXPORT( FT_Error )
  FT_Bitmap_Convert( FT_Library        library,
                     const FT_Bitmap  *source,
                     FT_Bitmap        *target,
                     FT_Int            alignment );

Convert a bitmap object with depth 1bpp, 2bpp, 4bpp, 8bpp or 32bpp to a bitmap object with depth 8bpp, making the number of used bytes line (a.k.a. the ‘pitch’) a multiple of ‘alignment’.

input

library

A handle to a library object.

source

The source bitmap.

alignment

The pitch of the bitmap is a multiple of this parameter. Common values are 1, 2, or 4.

output

target

The target bitmap.

return

FreeType error code. 0 means success.

note

It is possible to call FT_Bitmap_Convert multiple times without calling FT_Bitmap_Done (the memory is simply reallocated).

Use FT_Bitmap_Done to finally remove the bitmap object.

The ‘library’ argument is taken to have access to FreeType's memory handling functions.


FT_GlyphSlot_Own_Bitmap

Defined in FT_BITMAP_H (freetype/ftbitmap.h).

  FT_EXPORT( FT_Error )
  FT_GlyphSlot_Own_Bitmap( FT_GlyphSlot  slot );

Make sure that a glyph slot owns ‘slot->bitmap’.

input

slot

The glyph slot.

return

FreeType error code. 0 means success.

note

This function is to be used in combination with FT_Bitmap_Embolden.


FT_Bitmap_Done

Defined in FT_BITMAP_H (freetype/ftbitmap.h).

  FT_EXPORT( FT_Error )
  FT_Bitmap_Done( FT_Library  library,
                  FT_Bitmap  *bitmap );

Destroy a bitmap object initialized with FT_Bitmap_Init.

input

library

A handle to a library object.

bitmap

The bitmap object to be freed.

return

FreeType error code. 0 means success.

note

The ‘library’ argument is taken to have access to FreeType's memory handling functions.