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
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
|
/* This file is taken from the FreeType (1) tree. It's been reindented
* to roughly match Pango guidelines (in anticipation of future changes),
* but not otherwise much altered.
*/
/****************************************************************************/
/* */
/* The FreeType project -- a free and portable quality TrueType renderer. */
/* */
/* Copyright 1996-2000 by */
/* D. Turner, R.Wilhelm, and W. Lemberg */
/* */
/* arabic -- An implementation of the contextual algorithm given in the */
/* Unicode 2.0 book to assign the `isolated', `initial', `medial', and */
/* `final' properties to an input string of character codes for the Arabic */
/* script. */
/* */
/****************************************************************************/
#include "arabic-ot.h"
/*
*
* Here a table of the joining classes for characters in the range
* U+0620 - U+06FF.
*
* The following character also has a joining class:
*
* U+200C ZERO WIDTH NON-JOINER -> causing
*
* All other characters are given the joining class `none'.
*
*/
joining_class arabic[] =
{
/* U+0620 */
none, none, right, right,
right, right, dual, right,
dual, right, dual, dual,
dual, dual, dual, right,
/* U+0630 */
right, right, right, dual,
dual, dual, dual, dual,
dual, dual, dual, none,
none, none, none, none,
/* U+0640 */
causing, dual, dual, dual,
dual, dual, dual, dual,
right, right, dual, transparent,
transparent, transparent, transparent, transparent,
/* U+0650 */
transparent, transparent, transparent, none,
none, none, none, none,
none, none, none, none,
none, none, none, none,
/* U+0660 */
none, none, none, none,
none, none, none, none,
none, none, none, none,
none, none, none, none,
/* U+0670 */
transparent, none, right, right,
none, right, right, right,
dual, dual, dual, dual,
dual, dual, dual, dual,
/* U+0680 */
dual, dual, dual, dual,
dual, dual, dual, dual,
right, right, right, right,
right, right, right, right,
/* U+0690 */
right, right, right, right,
right, right, right, right,
right, right, dual, dual,
dual, dual, dual, dual,
/* U+06A0 */
dual, dual, dual, dual,
dual, dual, dual, dual,
dual, dual, dual, dual,
dual, dual, dual, dual,
/* U+06B0 */
dual, dual, dual, dual,
dual, dual, dual, dual,
dual, dual, dual, dual,
dual, dual, dual, dual,
/* U+06C0 */
right, dual, right, right,
right, right, right, right,
right, right, right, right,
dual, right, dual, right,
/* U+06D0 */
dual, dual, right, right,
none, none, none, transparent,
transparent, transparent, transparent, transparent,
transparent, transparent, transparent, transparent,
/* U+06E0 */
transparent, transparent, transparent, transparent,
transparent, none, none, transparent,
transparent, none, transparent, transparent,
transparent, transparent, none, none,
/* U+06F0 */
none, none, none, none,
none, none, none, none,
none, none, dual, dual,
dual, none, none, none
};
#if 0
struct cgc_
{
FT_UShort char_code;
FT_UShort glyph_index;
FT_UShort class;
};
typedef struct cgc_ cgc;
int compare_cgc (const void* a,
const void* b)
{
return (((cgc*)a)->glyph_index > ((cgc*)b)->glyph_index) ?
1 : ((((cgc*)a)->glyph_index == ((cgc*)b)->glyph_index) ?
0 : -1);
}
TT_Error Build_Arabic_Glyph_Properties (TT_CharMap char_map,
TT_UShort max_glyphs,
TTO_GDEFHeader** gdef)
{
TT_UShort i, j, num_glyphs;
cgc Arabic[0x0700 - 0x0620];
TT_UShort glyph_indices[0x700 - 0x0620];
TT_UShort classes[0x700 - 0x0620];
if (!gdef)
return TT_Err_Invalid_Argument;
j = 0;
for (i = 0x0620; i < 0x0700; i++)
{
Arabic[j].char_code = i;
Arabic[j].class = (arabic[i - 0x0620] == transparent) ?
MARK_GLYPH : SIMPLE_GLYPH;
Arabic[j].glyph_index = TT_Char_Index (char_map, i);
if (Arabic[j].glyph_index)
j++;
}
num_glyphs = j;
if (!num_glyphs)
{
/* no Arabic font */
*gdef = NULL;
return TT_Err_Ok;
}
/* sort it */
qsort (Arabic, num_glyphs, sizeof (cgc), compare_cgc);
/* write it to the arrays, removing duplicates */
glyph_indices[0] = Arabic[0].glyph_index;
classes[0] = Arabic[0].class;
j = 1;
for (i = 1; i < num_glyphs; i++)
{
glyph_indices[j] = Arabic[i].glyph_index;
classes[j] = Arabic[i].class;
if (glyph_indices[j - 1] != glyph_indices[j])
j++;
}
num_glyphs = j;
TT_GDEF_Build_ClassDefinition (*gdef, max_glyphs, num_glyphs,
glyph_indices, classes);
return TT_Err_Ok;
}
#endif
/* The joining rules as given in the Unicode 2.0 book (characters are
* here specified as appearing in the byte stream, i.e. *not* in
* visual order). Joining classes are given in angle brackets, glyph
* forms in square brackets. Glyphs affected by a specific rule are
* enclosed with vertical bars.
*
* Note: The description of the joining algorithm in the book is
* severely broken. You can get a corrected version from
* www.unicode.org (as of 29-Jun-1999, this hasn't appeared).
*
* R1: <anything1> <transparent> <anything2>
*
* apply joining rules for
* <anything1> <anything2> -> [shape1] [shape2]
*
* -> [shape1] [isolated] [shape2]
*
* R2: <causing|left|dual> |<right>|
*
* -> [final]
*
* R3: |<left>| <causing|right|dual>
*
* -> [initial]
*
* R4: <causing|left|dual> |<dual>| <causing|right|dual>
*
* -> [medial]
*
* R5: <causing|left|dual> |<dual>| <!(causing|right|dual)>
*
* -> [final]
*
* R6: <!(causing|left|dual)> |<dual>| <causing|right|dual>
*
* -> [initial]
*
* R7: If R1-R6 fail:
*
* <anything> -> [isolated]
*/
/* `direction' can be -1, 0, or 1 to indicate the last non-transparent
* glyph, the current glyph, and the next non-transparent glyph,
* respectively.
*/
static joining_class Get_Joining_Class (gunichar* string,
int pos,
int length,
int direction)
{
joining_class j;
while (1)
{
if (pos == 0 && direction < 0)
return none;
pos += direction;
if (pos >= length)
return none;
if (string[pos] < 0x0620 ||
string[pos] >= 0x0700)
{
if (string[pos] == 0x200C)
return causing;
else
return none;
}
else
j = arabic[string[pos] - 0x0620];
if (!direction || j != transparent)
return j;
}
}
FT_Error Assign_Arabic_Properties (gunichar *string,
gulong *properties,
int length)
{
joining_class previous, current, next;
int i;
if (!string || !properties || length == 0)
return FT_Err_Invalid_Argument;
for (i = 0; i < length; i++)
{
previous = Get_Joining_Class (string, i, length, -1);
current = Get_Joining_Class (string, i, length, 0);
next = Get_Joining_Class (string, i, length, 1);
/* R1 */
if (current == transparent)
{
properties[i] |= isolated_p;
continue;
}
/* R2 */
if (previous == causing ||
previous == left ||
previous == dual )
if (current == right)
{
properties[i] |= final_p;
continue;
}
/* R3 */
if (current == left)
if (next == causing ||
next == right ||
next == dual )
{
properties[i] |= initial_p;
continue;
}
/* R4 */
if (previous == causing ||
previous == left ||
previous == dual )
if (current == dual)
if (next == causing ||
next == right ||
next == dual )
{
properties[i] |= medial_p;
continue;
}
/* R5 */
if (previous == causing ||
previous == left ||
previous == dual )
if (current == dual)
if (!(next == causing ||
next == right ||
next == dual ))
{
properties[i] |= final_p;
continue;
}
/* R6 */
if (!(previous == causing ||
previous == left ||
previous == dual ))
if (current == dual)
if (next == causing ||
next == right ||
next == dual )
{
properties[i] |= initial_p;
continue;
}
/* R7 */
properties[i] |= isolated_p;
}
return FT_Err_Ok;
}
/* End */
|
