1#ifndef OT_LAYOUT_GPOS_GPOS_HH
2#define OT_LAYOUT_GPOS_GPOS_HH
3
4#include "../../../hb-ot-layout-common.hh"
5#include "../../../hb-ot-layout-gsubgpos.hh"
6#include "Common.hh"
7#include "PosLookup.hh"
8
9namespace OT {
10
11using Layout::GPOS_impl::PosLookup;
12
13namespace Layout {
14
15static void
16propagate_attachment_offsets (hb_glyph_position_t *pos,
17 unsigned int len,
18 unsigned int i,
19 hb_direction_t direction,
20 unsigned nesting_level = HB_MAX_NESTING_LEVEL);
21
22/*
23 * GPOS -- Glyph Positioning
24 * https://docs.microsoft.com/en-us/typography/opentype/spec/gpos
25 */
26
27struct GPOS : GSUBGPOS
28{
29 static constexpr hb_tag_t tableTag = HB_OT_TAG_GPOS;
30
31 using Lookup = PosLookup;
32
33 const PosLookup& get_lookup (unsigned int i) const
34 { return static_cast<const PosLookup &> (GSUBGPOS::get_lookup (i)); }
35
36 static inline void position_start (hb_font_t *font, hb_buffer_t *buffer);
37 static inline void position_finish_advances (hb_font_t *font, hb_buffer_t *buffer);
38 static inline void position_finish_offsets (hb_font_t *font, hb_buffer_t *buffer);
39
40 bool subset (hb_subset_context_t *c) const
41 {
42 hb_subset_layout_context_t l (c, tableTag);
43 return GSUBGPOS::subset<PosLookup> (&l);
44 }
45
46 bool sanitize (hb_sanitize_context_t *c) const
47 {
48 TRACE_SANITIZE (this);
49 return_trace (GSUBGPOS::sanitize<PosLookup> (c));
50 }
51
52 HB_INTERNAL bool is_blocklisted (hb_blob_t *blob,
53 hb_face_t *face) const;
54
55 void collect_variation_indices (hb_collect_variation_indices_context_t *c) const
56 {
57 for (unsigned i = 0; i < GSUBGPOS::get_lookup_count (); i++)
58 {
59 if (!c->gpos_lookups->has (i)) continue;
60 const PosLookup &l = get_lookup (i);
61 l.dispatch (c);
62 }
63 }
64
65 void closure_lookups (hb_face_t *face,
66 const hb_set_t *glyphs,
67 hb_set_t *lookup_indexes /* IN/OUT */) const
68 { GSUBGPOS::closure_lookups<PosLookup> (face, glyphs, lookup_indexes); }
69
70 typedef GSUBGPOS::accelerator_t<GPOS> accelerator_t;
71};
72
73
74static void
75propagate_attachment_offsets (hb_glyph_position_t *pos,
76 unsigned int len,
77 unsigned int i,
78 hb_direction_t direction,
79 unsigned nesting_level)
80{
81 /* Adjusts offsets of attached glyphs (both cursive and mark) to accumulate
82 * offset of glyph they are attached to. */
83 int chain = pos[i].attach_chain(), type = pos[i].attach_type();
84 if (likely (!chain))
85 return;
86
87 pos[i].attach_chain() = 0;
88
89 unsigned int j = (int) i + chain;
90
91 if (unlikely (j >= len))
92 return;
93
94 if (unlikely (!nesting_level))
95 return;
96
97 propagate_attachment_offsets (pos, len, j, direction, nesting_level - 1);
98
99 assert (!!(type & GPOS_impl::ATTACH_TYPE_MARK) ^ !!(type & GPOS_impl::ATTACH_TYPE_CURSIVE));
100
101 if (type & GPOS_impl::ATTACH_TYPE_CURSIVE)
102 {
103 if (HB_DIRECTION_IS_HORIZONTAL (direction))
104 pos[i].y_offset += pos[j].y_offset;
105 else
106 pos[i].x_offset += pos[j].x_offset;
107 }
108 else /*if (type & GPOS_impl::ATTACH_TYPE_MARK)*/
109 {
110 pos[i].x_offset += pos[j].x_offset;
111 pos[i].y_offset += pos[j].y_offset;
112
113 assert (j < i);
114 if (HB_DIRECTION_IS_FORWARD (direction))
115 for (unsigned int k = j; k < i; k++) {
116 pos[i].x_offset -= pos[k].x_advance;
117 pos[i].y_offset -= pos[k].y_advance;
118 }
119 else
120 for (unsigned int k = j + 1; k < i + 1; k++) {
121 pos[i].x_offset += pos[k].x_advance;
122 pos[i].y_offset += pos[k].y_advance;
123 }
124 }
125}
126
127void
128GPOS::position_start (hb_font_t *font HB_UNUSED, hb_buffer_t *buffer)
129{
130 unsigned int count = buffer->len;
131 for (unsigned int i = 0; i < count; i++)
132 buffer->pos[i].attach_chain() = buffer->pos[i].attach_type() = 0;
133}
134
135void
136GPOS::position_finish_advances (hb_font_t *font HB_UNUSED, hb_buffer_t *buffer HB_UNUSED)
137{
138 //_hb_buffer_assert_gsubgpos_vars (buffer);
139}
140
141void
142GPOS::position_finish_offsets (hb_font_t *font, hb_buffer_t *buffer)
143{
144 _hb_buffer_assert_gsubgpos_vars (buffer);
145
146 unsigned int len;
147 hb_glyph_position_t *pos = hb_buffer_get_glyph_positions (buffer, &len);
148 hb_direction_t direction = buffer->props.direction;
149
150 /* Handle attachments */
151 if (buffer->scratch_flags & HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT)
152 for (unsigned i = 0; i < len; i++)
153 propagate_attachment_offsets (pos, len, i, direction);
154
155 if (unlikely (font->slant))
156 {
157 for (unsigned i = 0; i < len; i++)
158 if (unlikely (pos[i].y_offset))
159 pos[i].x_offset += roundf (font->slant_xy * pos[i].y_offset);
160 }
161}
162
163}
164
165struct GPOS_accelerator_t : Layout::GPOS::accelerator_t {
166 GPOS_accelerator_t (hb_face_t *face) : Layout::GPOS::accelerator_t (face) {}
167};
168
169}
170
171#endif /* OT_LAYOUT_GPOS_GPOS_HH */
172