[ft-devel] Normalize the font matrix in cffobjs.c

[Ning Dong]

Hi, Werner

 

I'm reading the codes of FT2. In cffobjs.c, it said that "Normalize the font matrix so that `matrix->xx' is 1 ...", but the code is

     {

        FT_Matrix*  matrix = &dict->font_matrix;

        FT_Vector*  offset = &dict->font_offset;

        FT_ULong*   upm    = &dict->units_per_em;

        FT_Fixed    temp   = FT_ABS( matrix->yy );         //Why is yy? Should be matrix->xx?

 

        if ( temp != 0x10000L )

        {

          *upm = FT_DivFix( *upm, temp );

          matrix->xx = FT_DivFix( matrix->xx, temp );

          matrix->yx = FT_DivFix( matrix->yx, temp );

          matrix->xy = FT_DivFix( matrix->xy, temp );

          matrix->yy = FT_DivFix( matrix->yy, temp );

          offset->x  = FT_DivFix( offset->x,  temp );

          offset->y  = FT_DivFix( offset->y,  temp );

        }

        offset->x >>= 16; 

        offset->y >>= 16;

      }

 

In most case, it wouldn't cause error. But if yy != xx, the matrix is normalized that matrix->yy is 1.

 

BTW, this CFF_MAX_CID_FONTS limit in cfftypes.h is not mentioned in tn5176. Is it only a real-life limit?

As descibed in tn5176, it's possible to let each glyph has it's own Font DICT.

 

 

2009-03-11

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Ning Dong