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
_ft_face_scale_advances(FT_Face face,FT_Fixed * advances,FT_UInt count,FT_Int32 flags)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 )
FT_Get_Advance(FT_Face face,FT_UInt gindex,FT_Int32 flags,FT_Fixed * padvance)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 )
FT_Get_Advances(FT_Face face,FT_UInt start,FT_UInt count,FT_Int32 flags,FT_Fixed * padvances)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