lib/3rdparty/freetype/src/base/ftsynth.c

   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 if ( 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 */