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      1 /***************************************************************************/
      2 /*                                                                         */
      3 /*  ftsynth.c                                                              */
      4 /*                                                                         */
      5 /*    FreeType synthesizing code for emboldening and slanting (body).      */
      6 /*                                                                         */
      7 /*  Copyright 2000-2001, 2002, 2003, 2004, 2005, 2006, 2010 by             */
      8 /*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
      9 /*                                                                         */
     10 /*  This file is part of the FreeType project, and may only be used,       */
     11 /*  modified, and distributed under the terms of the FreeType project      */
     12 /*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
     13 /*  this file you indicate that you have read the license and              */
     14 /*  understand and accept it fully.                                        */
     15 /*                                                                         */
     16 /***************************************************************************/
     17 
     18 
     19 #include <ft2build.h>
     20 #include FT_SYNTHESIS_H
     21 #include FT_INTERNAL_DEBUG_H
     22 #include FT_INTERNAL_OBJECTS_H
     23 #include FT_OUTLINE_H
     24 #include FT_BITMAP_H
     25 
     26 
     27   /*************************************************************************/
     28   /*                                                                       */
     29   /* The macro FT_COMPONENT is used in trace mode.  It is an implicit      */
     30   /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log  */
     31   /* messages during execution.                                            */
     32   /*                                                                       */
     33 #undef  FT_COMPONENT
     34 #define FT_COMPONENT  trace_synth
     35 
     36   /*************************************************************************/
     37   /*************************************************************************/
     38   /****                                                                 ****/
     39   /****   EXPERIMENTAL OBLIQUING SUPPORT                                ****/
     40   /****                                                                 ****/
     41   /*************************************************************************/
     42   /*************************************************************************/
     43 
     44   /* documentation is in ftsynth.h */
     45 
     46   FT_EXPORT_DEF( void )
     47   FT_GlyphSlot_Oblique( FT_GlyphSlot  slot )
     48   {
     49     FT_Matrix    transform;
     50     FT_Outline*  outline = &slot->outline;
     51 
     52 
     53     /* only oblique outline glyphs */
     54     if ( slot->format != FT_GLYPH_FORMAT_OUTLINE )
     55       return;
     56 
     57     /* we don't touch the advance width */
     58 
     59     /* For italic, simply apply a shear transform, with an angle */
     60     /* of about 12 degrees.                                      */
     61 
     62     transform.xx = 0x10000L;
     63     transform.yx = 0x00000L;
     64 
     65     transform.xy = 0x06000L;
     66     transform.yy = 0x10000L;
     67 
     68     FT_Outline_Transform( outline, &transform );
     69   }
     70 
     71 
     72   /*************************************************************************/
     73   /*************************************************************************/
     74   /****                                                                 ****/
     75   /****   EXPERIMENTAL EMBOLDENING/OUTLINING SUPPORT                    ****/
     76   /****                                                                 ****/
     77   /*************************************************************************/
     78   /*************************************************************************/
     79 
     80 
     81   /* documentation is in ftsynth.h */
     82 
     83   FT_EXPORT_DEF( void )
     84   FT_GlyphSlot_Embolden( FT_GlyphSlot  slot )
     85   {
     86     FT_Library  library = slot->library;
     87     FT_Face     face    = slot->face;
     88     FT_Error    error;
     89     FT_Pos      xstr, ystr;
     90 
     91 
     92     if ( slot->format != FT_GLYPH_FORMAT_OUTLINE &&
     93          slot->format != FT_GLYPH_FORMAT_BITMAP  )
     94       return;
     95 
     96     /* some reasonable strength */
     97     xstr = FT_MulFix( face->units_per_EM,
     98                       face->size->metrics.y_scale ) / 24;
     99     ystr = xstr;
    100 
    101     if ( slot->format == FT_GLYPH_FORMAT_OUTLINE )
    102     {
    103       /* ignore error */
    104       (void)FT_Outline_Embolden( &slot->outline, xstr );
    105 
    106       /* this is more than enough for most glyphs; if you need accurate */
    107       /* values, you have to call FT_Outline_Get_CBox                   */
    108       xstr = xstr * 2;
    109       ystr = xstr;
    110     }
    111     else /* slot->format == FT_GLYPH_FORMAT_BITMAP */
    112     {
    113       /* round to full pixels */
    114       xstr &= ~63;
    115       if ( xstr == 0 )
    116         xstr = 1 << 6;
    117       ystr &= ~63;
    118 
    119       /*
    120        * XXX: overflow check for 16-bit system, for compatibility
    121        *      with FT_GlyphSlot_Embolden() since freetype-2.1.10.
    122        *      unfortunately, this function return no informations
    123        *      about the cause of error.
    124        */
    125       if ( ( ystr >> 6 ) > FT_INT_MAX || ( ystr >> 6 ) < FT_INT_MIN )
    126       {
    127         FT_TRACE1(( "FT_GlyphSlot_Embolden:" ));
    128         FT_TRACE1(( "too strong embolding parameter ystr=%d\n", ystr ));
    129         return;
    130       }
    131       error = FT_GlyphSlot_Own_Bitmap( slot );
    132       if ( error )
    133         return;
    134 
    135       error = FT_Bitmap_Embolden( library, &slot->bitmap, xstr, ystr );
    136       if ( error )
    137         return;
    138     }
    139 
    140     if ( slot->advance.x )
    141       slot->advance.x += xstr;
    142 
    143     if ( slot->advance.y )
    144       slot->advance.y += ystr;
    145 
    146     slot->metrics.width        += xstr;
    147     slot->metrics.height       += ystr;
    148     slot->metrics.horiBearingY += ystr;
    149     slot->metrics.horiAdvance  += xstr;
    150     slot->metrics.vertBearingX -= xstr / 2;
    151     slot->metrics.vertBearingY += ystr;
    152     slot->metrics.vertAdvance  += ystr;
    153 
    154     /* XXX: 16-bit overflow case must be excluded before here */
    155     if ( slot->format == FT_GLYPH_FORMAT_BITMAP )
    156       slot->bitmap_top += (FT_Int)( ystr >> 6 );
    157   }
    158 
    159 
    160 /* END */
    161