1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation. Oracle designates this
7 * particular file as subject to the "Classpath" exception as provided
8 * by Oracle in the LICENSE file that accompanied this code.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 /*
27 *
28 *
29 * (C) Copyright IBM Corp. 2004-2010 - All Rights Reserved
30 *
31 */
32
33 #include "KernTable.h"
34 #include "LEFontInstance.h"
35 #include "LEGlyphStorage.h"
36
37 #include "LESwaps.h"
38 #include "OpenTypeUtilities.h"
39
40 #include <stdio.h>
41
42 #define DEBUG 0
43
44 U_NAMESPACE_BEGIN
45
46 struct PairInfo {
47 le_uint32 key; // sigh, MSVC compiler gags on union here
48 le_int16 value; // fword, kern value in funits
49 };
50 #define KERN_PAIRINFO_SIZE 6
51 LE_CORRECT_SIZE(PairInfo, KERN_PAIRINFO_SIZE)
52 struct Subtable_0 {
53 le_uint16 nPairs;
54 le_uint16 searchRange;
55 le_uint16 entrySelector;
56 le_uint16 rangeShift;
57 };
58 #define KERN_SUBTABLE_0_HEADER_SIZE 8
59 LE_CORRECT_SIZE(Subtable_0, KERN_SUBTABLE_0_HEADER_SIZE)
60
61 // Kern table version 0 only
62 struct SubtableHeader {
63 le_uint16 version;
64 le_uint16 length;
65 le_uint16 coverage;
66 };
67 #define KERN_SUBTABLE_HEADER_SIZE 6
68 LE_CORRECT_SIZE(SubtableHeader, KERN_SUBTABLE_HEADER_SIZE)
69
70 // Version 0 only, version 1 has different layout
71 struct KernTableHeader {
72 le_uint16 version;
73 le_uint16 nTables;
74 };
75 #define KERN_TABLE_HEADER_SIZE 4
76 LE_CORRECT_SIZE(KernTableHeader, KERN_TABLE_HEADER_SIZE)
77
78 #define COVERAGE_HORIZONTAL 0x1
79 #define COVERAGE_MINIMUM 0x2
80 #define COVERAGE_CROSS 0x4
81 #define COVERAGE_OVERRIDE 0x8
82
83 /*
84 * This implementation has support for only one subtable, so if the font has
85 * multiple subtables, only the first will be used. If this turns out to
86 * be a problem in practice we should add it.
87 *
88 * This also supports only version 0 of the kern table header, only
89 * Apple supports the latter.
90 *
91 * This implementation isn't careful about the kern table flags, and
92 * might invoke kerning when it is not supposed to. That too I'm
93 * leaving for a bug fix.
94 *
95 * TODO: support multiple subtables
96 * TODO: respect header flags
97 */
98 KernTable::KernTable(const LETableReference& base, LEErrorCode &success)
99 : pairsSwapped(NULL), fTable(base)
100 {
101 if(LE_FAILURE(success) || (fTable.isEmpty())) {
102 #if DEBUG
103 fprintf(stderr, "no kern data\n");
104 #endif
105 return;
106 }
107 LEReferenceTo<KernTableHeader> header(fTable, success);
108
109 #if DEBUG
110 // dump first 32 bytes of header
111 for (int i = 0; i < 64; ++i) {
112 fprintf(stderr, "%0.2x ", ((const char*)header.getAlias())[i]&0xff);
113 if (((i+1)&0xf) == 0) {
114 fprintf(stderr, "\n");
115 } else if (((i+1)&0x7) == 0) {
116 fprintf(stderr, " ");
117 }
118 }
119 #endif
120
121 if(LE_FAILURE(success)) return;
122
123 if (!header.isEmpty() && header->version == 0 && SWAPW(header->nTables) > 0) {
124 LEReferenceTo<SubtableHeader> subhead(header, success, KERN_TABLE_HEADER_SIZE);
125
126 if (LE_SUCCESS(success) && !subhead.isEmpty() && subhead->version == 0) {
127 coverage = SWAPW(subhead->coverage);
128 if (coverage & COVERAGE_HORIZONTAL) { // only handle horizontal kerning
129 LEReferenceTo<Subtable_0> table(subhead, success, KERN_SUBTABLE_HEADER_SIZE);
130
131 if(table.isEmpty() || LE_FAILURE(success)) return;
132
133 nPairs = SWAPW(table->nPairs);
134
135 #if 0 // some old fonts have bad values here...
136 searchRange = SWAPW(table->searchRange);
137 entrySelector = SWAPW(table->entrySelector);
138 rangeShift = SWAPW(table->rangeShift);
139 #else
140 entrySelector = OpenTypeUtilities::highBit(nPairs);
141 searchRange = (1 << entrySelector) * KERN_PAIRINFO_SIZE;
142 rangeShift = (nPairs * KERN_PAIRINFO_SIZE) - searchRange;
143 #endif
144
145 if(LE_SUCCESS(success) && nPairs>0) {
146 // pairsSwapped is an instance member, and table is on the stack.
147 // set 'pairsSwapped' based on table.getAlias(). This will range check it.
148
149 pairsSwapped = (PairInfo*)(fTable.getFont()->getKernPairs());
150 if (pairsSwapped == NULL) {
151 LEReferenceToArrayOf<PairInfo>pairs =
152 LEReferenceToArrayOf<PairInfo>(fTable, // based on overall table
153 success,
154 (const PairInfo*)table.getAlias(), // subtable 0 + ..
155 KERN_SUBTABLE_0_HEADER_SIZE, // .. offset of header size
156 nPairs); // count
157 if (LE_SUCCESS(success) && pairs.isValid()) {
158 pairsSwapped = (PairInfo*)(malloc(nPairs*sizeof(PairInfo)));
159 PairInfo *p = (PairInfo*)pairsSwapped;
160 for (int i = 0; LE_SUCCESS(success) && i < nPairs; i++, p++) {
161 memcpy(p, pairs.getAlias(i,success), KERN_PAIRINFO_SIZE);
162 p->key = SWAPL(p->key);
163 }
164 fTable.getFont()->setKernPairs((void*)pairsSwapped); // store it
165 }
166 }
167 }
168
169 #if 0
170 fprintf(stderr, "coverage: %0.4x nPairs: %d pairs %p\n", coverage, nPairs, pairsSwapped);
171 fprintf(stderr, " searchRange: %d entrySelector: %d rangeShift: %d\n", searchRange, entrySelector, rangeShift);
172 fprintf(stderr, "[[ ignored font table entries: range %d selector %d shift %d ]]\n", SWAPW(table->searchRange), SWAPW(table->entrySelector), SWAPW(table->rangeShift));
173 #endif
174 #if DEBUG
175 fprintf(stderr, "coverage: %0.4x nPairs: %d pairs 0x%x\n", coverage, nPairs, pairsSwapped);
176 fprintf(stderr,
177 " searchRange(pairs): %d entrySelector: %d rangeShift(pairs): %d\n",
178 searchRange, entrySelector, rangeShift);
179
180 {
181 // dump part of the pair list
182 char ids[256];
183 for (int i = 256; --i >= 0;) {
184 LEGlyphID id = font->mapCharToGlyph(i);
185 if (id < 256) {
186 ids[id] = (char)i;
187 }
188 }
189 PairInfo *p = pairsSwapped;
190 for (int i = 0; i < nPairs; ++i, p++) {
191 le_uint32 k = p->key;
192 le_uint16 left = (k >> 16) & 0xffff;
193 le_uint16 right = k & 0xffff;
194 if (left < 256 && right < 256) {
195 char c = ids[left];
196 if (c > 0x20 && c < 0x7f) {
197 fprintf(stderr, "%c/", c & 0xff);
198 } else {
199 fprintf(stderr, "%0.2x/", c & 0xff);
200 }
201 c = ids[right];
202 if (c > 0x20 && c < 0x7f) {
203 fprintf(stderr, "%c ", c & 0xff);
204 } else {
205 fprintf(stderr, "%0.2x ", c & 0xff);
206 }
207 }
208 }
209 }
210 #endif
211 }
212 }
213 }
214 }
215
216
217 /*
218 * Process the glyph positions. The positions array has two floats for each
219 * glyph, plus a trailing pair to mark the end of the last glyph.
220 */
221 void KernTable::process(LEGlyphStorage& storage, LEErrorCode &success)
222 {
223 if(LE_FAILURE(success)) return;
224
225 if (pairsSwapped) {
226 success = LE_NO_ERROR;
227
228 le_uint32 key = storage[0]; // no need to mask off high bits
229 float adjust = 0;
230
231 for (int i = 1, e = storage.getGlyphCount(); LE_SUCCESS(success)&& i < e; ++i) {
232 key = key << 16 | (storage[i] & 0xffff);
233
234 // argh, to do a binary search, we need to have the pair list in sorted order
235 // but it is not in sorted order on win32 platforms because of the endianness difference
236 // so either I have to swap the element each time I examine it, or I have to swap
237 // all the elements ahead of time and store them in the font
238
239 const PairInfo* p = pairsSwapped;
240 const PairInfo* tp = (const PairInfo*)(p + (rangeShift/KERN_PAIRINFO_SIZE)); /* rangeshift is in original table bytes */
241 if (key > tp->key) {
242 p = tp;
243 }
244
245 #if DEBUG
246 fprintf(stderr, "binary search for %0.8x\n", key);
247 #endif
248
249 le_uint32 probe = searchRange;
250 while (probe > 1) {
251 probe >>= 1;
252 tp = (const PairInfo*)(p + (probe/KERN_PAIRINFO_SIZE));
253 le_uint32 tkey = tp->key;
254 #if DEBUG
255 fprintf(stdout, " %.3d (%0.8x)\n", (tp - pairsSwapped), tkey);
256 #endif
257 if (tkey <= key) {
258 if (tkey == key) {
259 le_int16 value = SWAPW(tp->value);
260 #if DEBUG
261 fprintf(stdout, "binary found kerning pair %x:%x at %d, value: 0x%x (%g)\n",
262 storage[i-1], storage[i], i, value & 0xffff, font->xUnitsToPoints(value));
263 fflush(stdout);
264 #endif
265 // Have to undo the device transform.
266 // REMIND either find a way to do this only if there is a
267 // device transform, or a faster way, such as moving the
268 // entire kern table up to Java.
269 LEPoint pt;
270 pt.fX = fTable.getFont()->xUnitsToPoints(value);
271 pt.fY = 0;
272
273 fTable.getFont()->getKerningAdjustment(pt);
274 adjust += pt.fX;
275 break;
276 }
277 p = tp;
278 }
279 }
280
281 storage.adjustPosition(i, adjust, 0, success);
282 }
283 storage.adjustPosition(storage.getGlyphCount(), adjust, 0, success);
284 }
285 }
286
287 U_NAMESPACE_END
288