/src/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 /* 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 */