xref: /aosp_15_r20/external/harfbuzz_ng/src/wasm/graphite/shape.cc (revision 2d1272b857b1f7575e6e246373e1cb218663db8a)
1 #define HB_WASM_INTERFACE(ret_t, name) __attribute__((export_name(#name))) ret_t name
2 
3 #include <hb-wasm-api.h>
4 
5 #include <graphite2/Segment.h>
6 
7 #include <stdlib.h>
8 #include <string.h>
9 
10 void debugprint1 (char *s, int32_t);
11 void debugprint2 (char *s, int32_t, int32_t);
12 
copy_table(const void * data,unsigned int tag,size_t * len)13 static const void *copy_table (const void *data, unsigned int tag, size_t *len)
14 {
15   face_t *face = (face_t *) data;
16   blob_t blob = BLOB_INIT;
17   if (!face_copy_table (face, tag, &blob))
18     abort ();
19 
20   *len = blob.length;
21   return blob.data;
22 }
23 
free_table(const void * data,const void * table_data)24 static void free_table (const void *data, const void *table_data)
25 {
26   blob_t blob;
27   blob.length = 0; // Doesn't matter
28   blob.data = (char *) table_data;
29   blob_free (&blob);
30 }
31 
32 void *
shape_plan_create(face_t * face)33 shape_plan_create (face_t *face)
34 {
35   const gr_face_ops ops = {sizeof (gr_face_ops), &copy_table, &free_table};
36   gr_face *grface = gr_make_face_with_ops (face, &ops, gr_face_preloadAll);
37   return grface;
38 }
39 
40 void
shape_plan_destroy(void * data)41 shape_plan_destroy (void *data)
42 {
43   gr_face_destroy ((gr_face *) data);
44 }
45 
46 bool_t
shape(void * shape_plan,font_t * font,buffer_t * buffer,const feature_t * features,uint32_t num_features)47 shape (void *shape_plan,
48        font_t *font,
49        buffer_t *buffer,
50        const feature_t *features,
51        uint32_t num_features)
52 {
53   face_t *face = font_get_face (font);
54   gr_face *grface = (gr_face *) shape_plan;
55 
56   direction_t direction = buffer_get_direction (buffer);
57   direction_t horiz_dir = script_get_horizontal_direction (buffer_get_script (buffer));
58   /* TODO vertical:
59    * The only BTT vertical script is Ogham, but it's not clear to me whether OpenType
60    * Ogham fonts are supposed to be implemented BTT or not.  Need to research that
61    * first. */
62   if ((DIRECTION_IS_HORIZONTAL (direction) &&
63        direction != horiz_dir && horiz_dir != DIRECTION_INVALID) ||
64       (DIRECTION_IS_VERTICAL   (direction) &&
65        direction != DIRECTION_TTB))
66   {
67     buffer_reverse_clusters (buffer);
68     direction = DIRECTION_REVERSE (direction);
69   }
70 
71   buffer_contents_t contents = BUFFER_CONTENTS_INIT;
72   if (!buffer_copy_contents (buffer, &contents))
73     return false;
74 
75   gr_segment *seg = nullptr;
76   const gr_slot *is;
77   unsigned int ci = 0, ic = 0;
78   unsigned int curradvx = 0, curradvy = 0;
79   unsigned length = contents.length;
80 
81   uint32_t *chars = (uint32_t *) malloc (length * sizeof (uint32_t));
82   if (!chars)
83     return false;
84   for (unsigned int i = 0; i < contents.length; ++i)
85     chars[i] = contents.info[i].codepoint;
86 
87   seg = gr_make_seg (nullptr, grface,
88 		     0, // https://github.com/harfbuzz/harfbuzz/issues/3439#issuecomment-1442650148
89 		     nullptr,
90 		     gr_utf32, chars, contents.length,
91 		     2 | (direction == DIRECTION_RTL ? 1 : 0));
92 
93   free (chars);
94 
95   if (!seg)
96     return false;
97 
98   unsigned int glyph_count = gr_seg_n_slots (seg);
99 
100   struct cluster_t {
101     unsigned int base_char;
102     unsigned int num_chars;
103     unsigned int base_glyph;
104     unsigned int num_glyphs;
105     unsigned int cluster;
106     int advance;
107   };
108 
109   length = glyph_count;
110   if (!buffer_contents_realloc (&contents, length))
111     return false;
112   cluster_t *clusters = (cluster_t *) malloc (length * sizeof (cluster_t));
113   uint32_t *gids = (uint32_t *) malloc (length * sizeof (uint32_t));
114   if (!clusters || !gids)
115   {
116     free (clusters);
117     free (gids);
118     return false;
119   }
120 
121   memset (clusters, 0, sizeof (clusters[0]) * length);
122   codepoint_t *pg = gids;
123   clusters[0].cluster = contents.info[0].cluster;
124   unsigned int upem = face_get_upem (face);
125   int32_t font_x_scale, font_y_scale;
126   font_get_scale (font, &font_x_scale, &font_y_scale);
127   float xscale = (float) font_x_scale / upem;
128   float yscale = (float) font_y_scale / upem;
129   yscale *= yscale / xscale;
130   unsigned int curradv = 0;
131   if (DIRECTION_IS_BACKWARD (direction))
132   {
133     curradv = gr_slot_origin_X(gr_seg_first_slot(seg)) * xscale;
134     clusters[0].advance = gr_seg_advance_X(seg) * xscale - curradv;
135   }
136   else
137     clusters[0].advance = 0;
138   for (is = gr_seg_first_slot (seg), ic = 0; is; is = gr_slot_next_in_segment (is), ic++)
139   {
140     unsigned int before = gr_slot_before (is);
141     unsigned int after = gr_slot_after (is);
142     *pg = gr_slot_gid (is);
143     pg++;
144     while (clusters[ci].base_char > before && ci)
145     {
146       clusters[ci-1].num_chars += clusters[ci].num_chars;
147       clusters[ci-1].num_glyphs += clusters[ci].num_glyphs;
148       clusters[ci-1].advance += clusters[ci].advance;
149       ci--;
150     }
151 
152     if (gr_slot_can_insert_before (is) && clusters[ci].num_chars && before >= clusters[ci].base_char + clusters[ci].num_chars)
153     {
154       cluster_t *c = clusters + ci + 1;
155       c->base_char = clusters[ci].base_char + clusters[ci].num_chars;
156       c->cluster = contents.info[c->base_char].cluster;
157       c->num_chars = before - c->base_char;
158       c->base_glyph = ic;
159       c->num_glyphs = 0;
160       if (DIRECTION_IS_BACKWARD (direction))
161       {
162 	c->advance = curradv - gr_slot_origin_X(is) * xscale;
163 	curradv -= c->advance;
164       }
165       else
166       {
167 	auto origin_X = gr_slot_origin_X (is) * xscale;
168 	c->advance = 0;
169 	clusters[ci].advance += origin_X - curradv;
170 	curradv = origin_X;
171       }
172       ci++;
173     }
174     clusters[ci].num_glyphs++;
175 
176     if (clusters[ci].base_char + clusters[ci].num_chars < after + 1)
177 	clusters[ci].num_chars = after + 1 - clusters[ci].base_char;
178   }
179 
180   if (DIRECTION_IS_BACKWARD (direction))
181     clusters[ci].advance += curradv;
182   else
183     clusters[ci].advance += gr_seg_advance_X(seg) * xscale - curradv;
184   ci++;
185 
186   for (unsigned int i = 0; i < ci; ++i)
187   {
188     for (unsigned int j = 0; j < clusters[i].num_glyphs; ++j)
189     {
190       glyph_info_t *info = &contents.info[clusters[i].base_glyph + j];
191       info->codepoint = gids[clusters[i].base_glyph + j];
192       info->cluster = clusters[i].cluster;
193       info->var1 = (unsigned) clusters[i].advance;     // all glyphs in the cluster get the same advance
194     }
195   }
196   contents.length = glyph_count;
197 
198   /* Positioning. */
199   unsigned int currclus = 0xFFFFFFFF;
200   const glyph_info_t *info = contents.info;
201   glyph_position_t *pPos = contents.pos;
202   if (!DIRECTION_IS_BACKWARD (direction))
203   {
204     curradvx = 0;
205     for (is = gr_seg_first_slot (seg); is; pPos++, ++info, is = gr_slot_next_in_segment (is))
206     {
207       pPos->x_offset = gr_slot_origin_X (is) * xscale - curradvx;
208       pPos->y_offset = gr_slot_origin_Y (is) * yscale - curradvy;
209       if (info->cluster != currclus) {
210 	pPos->x_advance = (int) info->var1;
211 	curradvx += pPos->x_advance;
212 	currclus = info->cluster;
213       } else
214 	pPos->x_advance = 0.;
215 
216       pPos->y_advance = gr_slot_advance_Y (is, grface, nullptr) * yscale;
217       curradvy += pPos->y_advance;
218     }
219     buffer_set_contents (buffer, &contents);
220   }
221   else
222   {
223     curradvx = gr_seg_advance_X(seg) * xscale;
224     for (is = gr_seg_first_slot (seg); is; pPos++, info++, is = gr_slot_next_in_segment (is))
225     {
226       if (info->cluster != currclus)
227       {
228 	pPos->x_advance = (int) info->var1;
229 	curradvx -= pPos->x_advance;
230 	currclus = info->cluster;
231       } else
232 	pPos->x_advance = 0.;
233 
234       pPos->y_advance = gr_slot_advance_Y (is, grface, nullptr) * yscale;
235       curradvy -= pPos->y_advance;
236       pPos->x_offset = gr_slot_origin_X (is) * xscale - (int) info->var1 - curradvx + pPos->x_advance;
237       pPos->y_offset = gr_slot_origin_Y (is) * yscale - curradvy;
238     }
239     buffer_set_contents (buffer, &contents);
240     buffer_reverse_clusters (buffer);
241   }
242 
243   gr_seg_destroy (seg);
244   free (clusters);
245   free (gids);
246 
247   bool ret = glyph_count;
248 
249   return ret;
250 }
251