1/***************************************************************************/
2/*                                                                         */
3/*  ftadvanc.c                                                             */
4/*                                                                         */
5/*    Quick computation of advance widths (body).                          */
6/*                                                                         */
7/*  Copyright 2008, 2009, 2011, 2013 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_INTERNAL_DEBUG_H
21
22#include FT_ADVANCES_H
23#include FT_INTERNAL_OBJECTS_H
24
25
26  static FT_Error
27  _ft_face_scale_advances( FT_Face    face,
28                           FT_Fixed*  advances,
29                           FT_UInt    count,
30                           FT_Int32   flags )
31  {
32    FT_Fixed  scale;
33    FT_UInt   nn;
34
35
36    if ( flags & FT_LOAD_NO_SCALE )
37      return FT_Err_Ok;
38
39    if ( face->size == NULL )
40      return FT_THROW( Invalid_Size_Handle );
41
42    if ( flags & FT_LOAD_VERTICAL_LAYOUT )
43      scale = face->size->metrics.y_scale;
44    else
45      scale = face->size->metrics.x_scale;
46
47    /* this must be the same scaling as to get linear{Hori,Vert}Advance */
48    /* (see `FT_Load_Glyph' implementation in src/base/ftobjs.c)        */
49
50    for ( nn = 0; nn < count; nn++ )
51      advances[nn] = FT_MulDiv( advances[nn], scale, 64 );
52
53    return FT_Err_Ok;
54  }
55
56
57   /* at the moment, we can perform fast advance retrieval only in */
58   /* the following cases:                                         */
59   /*                                                              */
60   /*  - unscaled load                                             */
61   /*  - unhinted load                                             */
62   /*  - light-hinted load                                         */
63
64#define LOAD_ADVANCE_FAST_CHECK( flags )                            \
65          ( flags & ( FT_LOAD_NO_SCALE | FT_LOAD_NO_HINTING )    || \
66            FT_LOAD_TARGET_MODE( flags ) == FT_RENDER_MODE_LIGHT )
67
68
69  /* documentation is in ftadvanc.h */
70
71  FT_EXPORT_DEF( FT_Error )
72  FT_Get_Advance( FT_Face    face,
73                  FT_UInt    gindex,
74                  FT_Int32   flags,
75                  FT_Fixed  *padvance )
76  {
77    FT_Face_GetAdvancesFunc  func;
78
79
80    if ( !face )
81      return FT_THROW( Invalid_Face_Handle );
82
83    if ( gindex >= (FT_UInt)face->num_glyphs )
84      return FT_THROW( Invalid_Glyph_Index );
85
86    func = face->driver->clazz->get_advances;
87    if ( func && LOAD_ADVANCE_FAST_CHECK( flags ) )
88    {
89      FT_Error  error;
90
91
92      error = func( face, gindex, 1, flags, padvance );
93      if ( !error )
94        return _ft_face_scale_advances( face, padvance, 1, flags );
95
96      if ( FT_ERR_NEQ( error, Unimplemented_Feature ) )
97        return error;
98    }
99
100    return FT_Get_Advances( face, gindex, 1, flags, padvance );
101  }
102
103
104  /* documentation is in ftadvanc.h */
105
106  FT_EXPORT_DEF( FT_Error )
107  FT_Get_Advances( FT_Face    face,
108                   FT_UInt    start,
109                   FT_UInt    count,
110                   FT_Int32   flags,
111                   FT_Fixed  *padvances )
112  {
113    FT_Face_GetAdvancesFunc  func;
114    FT_UInt                  num, end, nn;
115    FT_Error                 error = FT_Err_Ok;
116
117
118    if ( !face )
119      return FT_THROW( Invalid_Face_Handle );
120
121    num = (FT_UInt)face->num_glyphs;
122    end = start + count;
123    if ( start >= num || end < start || end > num )
124      return FT_THROW( Invalid_Glyph_Index );
125
126    if ( count == 0 )
127      return FT_Err_Ok;
128
129    func = face->driver->clazz->get_advances;
130    if ( func && LOAD_ADVANCE_FAST_CHECK( flags ) )
131    {
132      error = func( face, start, count, flags, padvances );
133      if ( !error )
134        return _ft_face_scale_advances( face, padvances, count, flags );
135
136      if ( FT_ERR_NEQ( error, Unimplemented_Feature ) )
137        return error;
138    }
139
140    error = FT_Err_Ok;
141
142    if ( flags & FT_ADVANCE_FLAG_FAST_ONLY )
143      return FT_THROW( Unimplemented_Feature );
144
145    flags |= (FT_UInt32)FT_LOAD_ADVANCE_ONLY;
146    for ( nn = 0; nn < count; nn++ )
147    {
148      error = FT_Load_Glyph( face, start + nn, flags );
149      if ( error )
150        break;
151
152      /* scale from 26.6 to 16.16 */
153      padvances[nn] = ( flags & FT_LOAD_VERTICAL_LAYOUT )
154                      ? face->glyph->advance.y << 10
155                      : face->glyph->advance.x << 10;
156    }
157
158    return error;
159  }
160
161
162/* END */
163