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