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
160
161
162
163
164
165
166
167
168
169
170
171
|
#ifndef OT_LAYOUT_GPOS_GPOS_HH
#define OT_LAYOUT_GPOS_GPOS_HH
#include "../../../hb-ot-layout-common.hh"
#include "../../../hb-ot-layout-gsubgpos.hh"
#include "Common.hh"
#include "PosLookup.hh"
namespace OT {
using Layout::GPOS_impl::PosLookup;
namespace Layout {
static void
propagate_attachment_offsets (hb_glyph_position_t *pos,
unsigned int len,
unsigned int i,
hb_direction_t direction,
unsigned nesting_level = HB_MAX_NESTING_LEVEL);
/*
* GPOS -- Glyph Positioning
* https://docs.microsoft.com/en-us/typography/opentype/spec/gpos
*/
struct GPOS : GSUBGPOS
{
static constexpr hb_tag_t tableTag = HB_OT_TAG_GPOS;
using Lookup = PosLookup;
const PosLookup& get_lookup (unsigned int i) const
{ return static_cast<const PosLookup &> (GSUBGPOS::get_lookup (i)); }
static inline void position_start (hb_font_t *font, hb_buffer_t *buffer);
static inline void position_finish_advances (hb_font_t *font, hb_buffer_t *buffer);
static inline void position_finish_offsets (hb_font_t *font, hb_buffer_t *buffer);
bool subset (hb_subset_context_t *c) const
{
hb_subset_layout_context_t l (c, tableTag);
return GSUBGPOS::subset<PosLookup> (&l);
}
bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (GSUBGPOS::sanitize<PosLookup> (c));
}
HB_INTERNAL bool is_blocklisted (hb_blob_t *blob,
hb_face_t *face) const;
void collect_variation_indices (hb_collect_variation_indices_context_t *c) const
{
for (unsigned i = 0; i < GSUBGPOS::get_lookup_count (); i++)
{
if (!c->gpos_lookups->has (i)) continue;
const PosLookup &l = get_lookup (i);
l.dispatch (c);
}
}
void closure_lookups (hb_face_t *face,
const hb_set_t *glyphs,
hb_set_t *lookup_indexes /* IN/OUT */) const
{ GSUBGPOS::closure_lookups<PosLookup> (face, glyphs, lookup_indexes); }
typedef GSUBGPOS::accelerator_t<GPOS> accelerator_t;
};
static void
propagate_attachment_offsets (hb_glyph_position_t *pos,
unsigned int len,
unsigned int i,
hb_direction_t direction,
unsigned nesting_level)
{
/* Adjusts offsets of attached glyphs (both cursive and mark) to accumulate
* offset of glyph they are attached to. */
int chain = pos[i].attach_chain(), type = pos[i].attach_type();
if (likely (!chain))
return;
pos[i].attach_chain() = 0;
unsigned int j = (int) i + chain;
if (unlikely (j >= len))
return;
if (unlikely (!nesting_level))
return;
propagate_attachment_offsets (pos, len, j, direction, nesting_level - 1);
assert (!!(type & GPOS_impl::ATTACH_TYPE_MARK) ^ !!(type & GPOS_impl::ATTACH_TYPE_CURSIVE));
if (type & GPOS_impl::ATTACH_TYPE_CURSIVE)
{
if (HB_DIRECTION_IS_HORIZONTAL (direction))
pos[i].y_offset += pos[j].y_offset;
else
pos[i].x_offset += pos[j].x_offset;
}
else /*if (type & GPOS_impl::ATTACH_TYPE_MARK)*/
{
pos[i].x_offset += pos[j].x_offset;
pos[i].y_offset += pos[j].y_offset;
assert (j < i);
if (HB_DIRECTION_IS_FORWARD (direction))
for (unsigned int k = j; k < i; k++) {
pos[i].x_offset -= pos[k].x_advance;
pos[i].y_offset -= pos[k].y_advance;
}
else
for (unsigned int k = j + 1; k < i + 1; k++) {
pos[i].x_offset += pos[k].x_advance;
pos[i].y_offset += pos[k].y_advance;
}
}
}
void
GPOS::position_start (hb_font_t *font HB_UNUSED, hb_buffer_t *buffer)
{
unsigned int count = buffer->len;
for (unsigned int i = 0; i < count; i++)
buffer->pos[i].attach_chain() = buffer->pos[i].attach_type() = 0;
}
void
GPOS::position_finish_advances (hb_font_t *font HB_UNUSED, hb_buffer_t *buffer HB_UNUSED)
{
//_hb_buffer_assert_gsubgpos_vars (buffer);
}
void
GPOS::position_finish_offsets (hb_font_t *font, hb_buffer_t *buffer)
{
_hb_buffer_assert_gsubgpos_vars (buffer);
unsigned int len;
hb_glyph_position_t *pos = hb_buffer_get_glyph_positions (buffer, &len);
hb_direction_t direction = buffer->props.direction;
/* Handle attachments */
if (buffer->scratch_flags & HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT)
for (unsigned i = 0; i < len; i++)
propagate_attachment_offsets (pos, len, i, direction);
if (unlikely (font->slant))
{
for (unsigned i = 0; i < len; i++)
if (unlikely (pos[i].y_offset))
pos[i].x_offset += _hb_roundf (font->slant_xy * pos[i].y_offset);
}
}
}
struct GPOS_accelerator_t : Layout::GPOS::accelerator_t {
GPOS_accelerator_t (hb_face_t *face) : Layout::GPOS::accelerator_t (face) {}
};
}
#endif /* OT_LAYOUT_GPOS_GPOS_HH */
|