Re: [ft-devel] Possible implementation error of function FT_Bitmap_Embolden()

[Werner LEMBERG]

> No, there isn't.  In your program, you do this:
> 
>   err_ebd = FT_Bitmap_Embolden(library, &emb_bitmap,
>                                xStrength, yStrength);
>   ((FT_BitmapGlyph)glyph)->bitmap = emb_bitmap;
>   FT_Glyph_Get_CBox(glyph, 0, &cbox);
> 
> Assigning the emboldened bitmap back to the FT_Glyph structure.

Oops!  This should read:

  Assigning the emboldened bitmap back to the FT_Glyph structure is
  not sufficient.

> While `width' and `row' are part of an FT_Bitmap structure, the
> `left' and `top' values are not.  The computation within
> FT_Glyph_Get_CBox thus returns the values you've observed.
> 
> Either update the `top' value in `FT_BitmapGlyph' by yourself or
> reuse the code from `FT_GlyphSlot_Embolden' (in `ftsynth.c'), which
> adjusts the `bitmap_top' field in the FT_GlyphSlot structure.


    Werner