RE: [Devel] losing less when calculating root->units_per_EM

[Tom Kacvinsky]

OK, I see that instead of the division (1 / tempscale / 1000 ), you are
approching this as 1000 / tempscale, which is 1 less division.  I will
add the code presently.

Regards,

Tom

On Wed, 29 Aug 2001, Erik Strik wrote:

> Dear Tom,
>
> I send this mail on behalf of Martin Muskens.
>
> The fonts are indeed originally TrueType fonts that are set to a non-1000-EM
> (indeed 2048 which is the TT standard). This happens with embedded fonts in
> PDF files.
>
> Kind regards,
>
> Erik Strik
> Aurelon
>
> -----Original Message-----
> From: Tom Kacvinsky [mailto:address@hidden
> Sent: dinsdag 28 augustus 2001 16:05
> To: address@hidden
> Subject: Re: [Devel] losing less when calculating root->units_per_EM
>
>
> How is it not precise enough?  Is it becuase of the multiple dvisions?  Did
> you try this with TT fonts that were autoconverted to Type 1 fonts, so that
> the units per EM is something like 2048?  Do you get the correct value for
> that?  Etc, etc...
>
> On Tue, 28 Aug 2001, Martin Muskens wrote:
>
> > Hi all,
> >
> > in the file t1load.c the calculation of root->units_per_EM is not precise
> > enough.
> > I think this is a better solution:
> >
> > bye
> > Martin Muskens
> > Aurelon
> >
> >
> > #ifdef AURELON
> > #define     Int2Fixed( x )  ( (FT_Fixed)( x ) << 16 )
> > #endif
> >
> >   static void
> >   parse_font_matrix( T1_Face     face,
> >                      T1_Loader*  loader )
> >   {
> >     T1_ParserRec*  parser = &loader->parser;
> >     FT_Matrix*     matrix = &face->type1.font_matrix;
> >     FT_Vector*     offset = &face->type1.font_offset;
> >     FT_Face        root   = (FT_Face)&face->root;
> >     FT_Fixed       temp[6];
> >     FT_Fixed       temp_scale;
> >
> >
> >     if ( matrix->xx || matrix->yx )
> >       /*  with synthetic fonts, it's possible we get here twice  */
> >       return;
> >
> >     (void)T1_ToFixedArray( parser, 6, temp, 3 );
> >
> >     temp_scale = ABS( temp[3] );
> >
> >     /* Set Units per EM based on FontMatrix values. We set the value to */
> >     /* 1000 / temp_scale, because temp_scale was already multiplied by  */
> >     /* 1000 (in t1_tofixed, from psobjs.c).                             */
> >
> > #ifdef AURELON
> >     root->units_per_EM = (FT_UShort)( FT_DivFix( Int2Fixed( 1000 ),
> > temp_scale ) >> 16 );
> > #else
> >     root->units_per_EM = (FT_UShort)FT_DivFix( 0x10000L,
> >                                                FT_DivFix( temp_scale, 1000
> )
> > );
> > #endif
> >
> >     /* we need to scale the values by 1.0/temp_scale */
> >     if ( temp_scale != 0x10000L )
> >     {
> >       temp[0] = FT_DivFix( temp[0], temp_scale );
> >       temp[1] = FT_DivFix( temp[1], temp_scale );
> >       temp[2] = FT_DivFix( temp[2], temp_scale );
> >       temp[4] = FT_DivFix( temp[4], temp_scale );
> >       temp[5] = FT_DivFix( temp[5], temp_scale );
> >       temp[3] = 0x10000L;
> >     }
> >
> >     matrix->xx = temp[0];
> >     matrix->yx = temp[1];
> >     matrix->xy = temp[2];
> >     matrix->yy = temp[3];
> >
> >     /* note that the offsets must be expressed in integer font units */
> >     offset->x  = temp[4] >> 16;
> >     offset->y  = temp[5] >> 16;
> >   }
> >
> > _______________________________________________
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> >
>
>
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