aboutsummaryrefslogtreecommitdiff
path: root/freetype/src/base/ftsynth.c
blob: 4a97e48524ecdc5736191c18d29a7e503ff7fd2b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
/***************************************************************************/
/*                                                                         */
/*  ftsynth.c                                                              */
/*                                                                         */
/*    FreeType synthesizing code for emboldening and slanting (body).      */
/*                                                                         */
/*  Copyright 2000-2001, 2002, 2003, 2004, 2005, 2006, 2010 by             */
/*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
/*                                                                         */
/*  This file is part of the FreeType project, and may only be used,       */
/*  modified, and distributed under the terms of the FreeType project      */
/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/***************************************************************************/


#include <ft2build.h>
#include FT_SYNTHESIS_H
#include <freetype/internal/ftobjs.h>
#include FT_OUTLINE_H
#include FT_BITMAP_H


  /*************************************************************************/
  /*                                                                       */
  /* The macro FT_COMPONENT is used in trace mode.  It is an implicit      */
  /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log  */
  /* messages during execution.                                            */
  /*                                                                       */
#undef  FT_COMPONENT
#define FT_COMPONENT  trace_synth

  /*************************************************************************/
  /*************************************************************************/
  /****                                                                 ****/
  /****   EXPERIMENTAL OBLIQUING SUPPORT                                ****/
  /****                                                                 ****/
  /*************************************************************************/
  /*************************************************************************/

  /* documentation is in ftsynth.h */

  FT_EXPORT_DEF( void )
  FT_GlyphSlot_Oblique( FT_GlyphSlot  slot )
  {
    FT_Matrix    transform;
    FT_Outline*  outline = &slot->outline;


    /* only oblique outline glyphs */
    if ( slot->format != FT_GLYPH_FORMAT_OUTLINE )
      return;

    /* we don't touch the advance width */

    /* For italic, simply apply a shear transform, with an angle */
    /* of about 12 degrees.                                      */

    transform.xx = 0x10000L;
    transform.yx = 0x00000L;

    transform.xy = 0x06000L;
    transform.yy = 0x10000L;

    FT_Outline_Transform( outline, &transform );
  }


  /*************************************************************************/
  /*************************************************************************/
  /****                                                                 ****/
  /****   EXPERIMENTAL EMBOLDENING/OUTLINING SUPPORT                    ****/
  /****                                                                 ****/
  /*************************************************************************/
  /*************************************************************************/


  /* documentation is in ftsynth.h */

  FT_EXPORT_DEF( void )
  FT_GlyphSlot_Embolden( FT_GlyphSlot  slot )
  {
    FT_Library  library = slot->library;
    FT_Face     face    = slot->face;
    FT_Error    error;
    FT_Pos      xstr, ystr;


    if ( slot->format != FT_GLYPH_FORMAT_OUTLINE &&
         slot->format != FT_GLYPH_FORMAT_BITMAP )
      return;

    /* some reasonable strength */
    xstr = FT_MulFix( face->units_per_EM,
                      face->size->metrics.y_scale ) / 24;
    ystr = xstr;

    if ( slot->format == FT_GLYPH_FORMAT_OUTLINE )
    {
      /* ignore error */
      (void)FT_Outline_Embolden( &slot->outline, xstr );

      /* this is more than enough for most glyphs; if you need accurate */
      /* values, you have to call FT_Outline_Get_CBox                   */
      xstr = xstr * 2;
      ystr = xstr;
    }
    else if ( slot->format == FT_GLYPH_FORMAT_BITMAP )
    {
      /* round to full pixels */
      xstr &= ~63;
      if ( xstr == 0 )
        xstr = 1 << 6;
      ystr &= ~63;

      /*
       * XXX: overflow check for 16-bit system, for compatibility
       *      with FT_GlyphSlot_Embolden() since freetype-2.1.10.
       *      unfortunately, this function return no informations
       *      about the cause of error.
       */
      if ( ( ystr >> 6 ) > FT_INT_MAX || ( ystr >> 6 ) < FT_INT_MIN )
      {
        FT_TRACE1(( "FT_GlyphSlot_Embolden:" ));
        FT_TRACE1(( "too strong embolding parameter ystr=%d\n", ystr ));
        return;
      }
      error = FT_GlyphSlot_Own_Bitmap( slot );
      if ( error )
        return;

      error = FT_Bitmap_Embolden( library, &slot->bitmap, xstr, ystr );
      if ( error )
        return;
    }

    if ( slot->advance.x )
      slot->advance.x += xstr;

    if ( slot->advance.y )
      slot->advance.y += ystr;

    slot->metrics.width        += xstr;
    slot->metrics.height       += ystr;
    slot->metrics.horiBearingY += ystr;
    slot->metrics.horiAdvance  += xstr;
    slot->metrics.vertBearingX -= xstr / 2;
    slot->metrics.vertBearingY += ystr;
    slot->metrics.vertAdvance  += ystr;

    /* XXX: 16-bit overflow case must be excluded before here */
    if ( slot->format == FT_GLYPH_FORMAT_BITMAP )
      slot->bitmap_top += (FT_Int)( ystr >> 6 );
  }


/* END */