1 | /**************************************************************************** |
2 | * |
3 | * ftadvanc.c |
4 | * |
5 | * Quick computation of advance widths (body). |
6 | * |
7 | * Copyright (C) 2008-2023 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 <freetype/internal/ftdebug.h> |
20 | |
21 | #include <freetype/ftadvanc.h> |
22 | #include <freetype/internal/ftobjs.h> |
23 | |
24 | |
25 | static FT_Error |
26 | ft_face_scale_advances_( FT_Face face, |
27 | FT_Fixed* advances, |
28 | FT_UInt count, |
29 | FT_Int32 flags ) |
30 | { |
31 | FT_Fixed scale; |
32 | FT_UInt nn; |
33 | |
34 | |
35 | if ( flags & FT_LOAD_NO_SCALE ) |
36 | return FT_Err_Ok; |
37 | |
38 | if ( !face->size ) |
39 | return FT_THROW( Invalid_Size_Handle ); |
40 | |
41 | if ( flags & FT_LOAD_VERTICAL_LAYOUT ) |
42 | scale = face->size->metrics.y_scale; |
43 | else |
44 | scale = face->size->metrics.x_scale; |
45 | |
46 | /* this must be the same scaling as to get linear{Hori,Vert}Advance */ |
47 | /* (see `FT_Load_Glyph' implementation in src/base/ftobjs.c) */ |
48 | |
49 | for ( nn = 0; nn < count; nn++ ) |
50 | advances[nn] = FT_MulDiv( advances[nn], scale, 64 ); |
51 | |
52 | return FT_Err_Ok; |
53 | } |
54 | |
55 | |
56 | /* at the moment, we can perform fast advance retrieval only in */ |
57 | /* the following cases: */ |
58 | /* */ |
59 | /* - unscaled load */ |
60 | /* - unhinted load */ |
61 | /* - light-hinted load */ |
62 | /* - if a variations font, it must have an `HVAR' or `VVAR' */ |
63 | /* table (thus the old MM or GX fonts don't qualify; this */ |
64 | /* gets checked by the driver-specific functions) */ |
65 | |
66 | #define LOAD_ADVANCE_FAST_CHECK( face, flags ) \ |
67 | ( flags & ( FT_LOAD_NO_SCALE | FT_LOAD_NO_HINTING ) || \ |
68 | FT_LOAD_TARGET_MODE( flags ) == FT_RENDER_MODE_LIGHT ) |
69 | |
70 | |
71 | /* documentation is in ftadvanc.h */ |
72 | |
73 | FT_EXPORT_DEF( FT_Error ) |
74 | FT_Get_Advance( FT_Face face, |
75 | FT_UInt gindex, |
76 | FT_Int32 flags, |
77 | FT_Fixed *padvance ) |
78 | { |
79 | FT_Face_GetAdvancesFunc func; |
80 | |
81 | |
82 | if ( !face ) |
83 | return FT_THROW( Invalid_Face_Handle ); |
84 | |
85 | if ( !padvance ) |
86 | return FT_THROW( Invalid_Argument ); |
87 | |
88 | if ( gindex >= (FT_UInt)face->num_glyphs ) |
89 | return FT_THROW( Invalid_Glyph_Index ); |
90 | |
91 | func = face->driver->clazz->get_advances; |
92 | if ( func && LOAD_ADVANCE_FAST_CHECK( face, flags ) ) |
93 | { |
94 | FT_Error error; |
95 | |
96 | |
97 | error = func( face, gindex, 1, flags, padvance ); |
98 | if ( !error ) |
99 | return ft_face_scale_advances_( face, padvance, 1, flags ); |
100 | |
101 | if ( FT_ERR_NEQ( error, Unimplemented_Feature ) ) |
102 | return error; |
103 | } |
104 | |
105 | return FT_Get_Advances( face, gindex, 1, flags, padvance ); |
106 | } |
107 | |
108 | |
109 | /* documentation is in ftadvanc.h */ |
110 | |
111 | FT_EXPORT_DEF( FT_Error ) |
112 | FT_Get_Advances( FT_Face face, |
113 | FT_UInt start, |
114 | FT_UInt count, |
115 | FT_Int32 flags, |
116 | FT_Fixed *padvances ) |
117 | { |
118 | FT_Error error = FT_Err_Ok; |
119 | |
120 | FT_Face_GetAdvancesFunc func; |
121 | |
122 | FT_UInt num, end, nn; |
123 | FT_Int factor; |
124 | |
125 | |
126 | if ( !face ) |
127 | return FT_THROW( Invalid_Face_Handle ); |
128 | |
129 | if ( !padvances ) |
130 | return FT_THROW( Invalid_Argument ); |
131 | |
132 | num = (FT_UInt)face->num_glyphs; |
133 | end = start + count; |
134 | if ( start >= num || end < start || end > num ) |
135 | return FT_THROW( Invalid_Glyph_Index ); |
136 | |
137 | if ( count == 0 ) |
138 | return FT_Err_Ok; |
139 | |
140 | func = face->driver->clazz->get_advances; |
141 | if ( func && LOAD_ADVANCE_FAST_CHECK( face, flags ) ) |
142 | { |
143 | error = func( face, start, count, flags, padvances ); |
144 | if ( !error ) |
145 | return ft_face_scale_advances_( face, padvances, count, flags ); |
146 | |
147 | if ( FT_ERR_NEQ( error, Unimplemented_Feature ) ) |
148 | return error; |
149 | } |
150 | |
151 | error = FT_Err_Ok; |
152 | |
153 | if ( flags & FT_ADVANCE_FLAG_FAST_ONLY ) |
154 | return FT_THROW( Unimplemented_Feature ); |
155 | |
156 | flags |= (FT_UInt32)FT_LOAD_ADVANCE_ONLY; |
157 | factor = ( flags & FT_LOAD_NO_SCALE ) ? 1 : 1024; |
158 | for ( nn = 0; nn < count; nn++ ) |
159 | { |
160 | error = FT_Load_Glyph( face, start + nn, flags ); |
161 | if ( error ) |
162 | break; |
163 | |
164 | /* scale from 26.6 to 16.16, unless NO_SCALE was requested */ |
165 | padvances[nn] = ( flags & FT_LOAD_VERTICAL_LAYOUT ) |
166 | ? face->glyph->advance.y * factor |
167 | : face->glyph->advance.x * factor; |
168 | } |
169 | |
170 | return error; |
171 | } |
172 | |
173 | |
174 | /* END */ |
175 | |