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 : pairs(), 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 // pairs is an instance member, and table is on the stack.
147 // set 'pairs' based on table.getAlias(). This will range check it.
148
149 pairs = LEReferenceToArrayOf<PairInfo>(fTable, // based on overall table
150 success,
151 (const PairInfo*)table.getAlias(), // subtable 0 + ..
152 KERN_SUBTABLE_0_HEADER_SIZE, // .. offset of header size
153 nPairs); // count
154 }
155 if (LE_SUCCESS(success) && pairs.isValid()) {
156 pairsSwapped = (PairInfo*)(malloc(nPairs*sizeof(PairInfo)));
157 PairInfo *p = (PairInfo*)pairsSwapped;
158 for (int i = 0; LE_SUCCESS(success) && i < nPairs; i++, p++) {
159 memcpy(p, pairs.getAlias(i,success), KERN_PAIRINFO_SIZE);
160 p->key = SWAPL(p->key);
161 }
162 fTable.getFont()->setKernPairs((void*)pairsSwapped); // store it
163 }
164
165 #if 0
166 fprintf(stderr, "coverage: %0.4x nPairs: %d pairs %p\n", coverage, nPairs, pairs.getAlias());
167 fprintf(stderr, " searchRange: %d entrySelector: %d rangeShift: %d\n", searchRange, entrySelector, rangeShift);
168 fprintf(stderr, "[[ ignored font table entries: range %d selector %d shift %d ]]\n", SWAPW(table->searchRange), SWAPW(table->entrySelector), SWAPW(table->rangeShift));
169 #endif
170 #if DEBUG
171 fprintf(stderr, "coverage: %0.4x nPairs: %d pairs 0x%x\n", coverage, nPairs, pairs);
172 fprintf(stderr,
173 " searchRange(pairs): %d entrySelector: %d rangeShift(pairs): %d\n",
174 searchRange, entrySelector, rangeShift);
175
176 {
177 // dump part of the pair list
178 char ids[256];
179 for (int i = 256; --i >= 0;) {
180 LEGlyphID id = font->mapCharToGlyph(i);
181 if (id < 256) {
182 ids[id] = (char)i;
183 }
184 }
185 PairInfo *p = pairs;
186 for (int i = 0; i < nPairs; ++i, p++) {
187 le_uint32 k = p->key;
188 le_uint16 left = (k >> 16) & 0xffff;
189 le_uint16 right = k & 0xffff;
190 if (left < 256 && right < 256) {
191 char c = ids[left];
192 if (c > 0x20 && c < 0x7f) {
193 fprintf(stderr, "%c/", c & 0xff);
194 } else {
195 fprintf(stderr, "%0.2x/", c & 0xff);
196 }
197 c = ids[right];
198 if (c > 0x20 && c < 0x7f) {
199 fprintf(stderr, "%c ", c & 0xff);
200 } else {
201 fprintf(stderr, "%0.2x ", c & 0xff);
202 }
203 }
204 }
205 }
206 #endif
207 }
208 }
209 }
210 }
211
212
213 /*
214 * Process the glyph positions. The positions array has two floats for each
215 * glyph, plus a trailing pair to mark the end of the last glyph.
216 */
217 void KernTable::process(LEGlyphStorage& storage, LEErrorCode &success)
218 {
219 if(LE_FAILURE(success)) return;
220
221 if (pairsSwapped) {
222 success = LE_NO_ERROR;
223
224 le_uint32 key = storage[0]; // no need to mask off high bits
225 float adjust = 0;
226
227 for (int i = 1, e = storage.getGlyphCount(); LE_SUCCESS(success)&& i < e; ++i) {
228 key = key << 16 | (storage[i] & 0xffff);
229
230 // argh, to do a binary search, we need to have the pair list in sorted order
231 // but it is not in sorted order on win32 platforms because of the endianness difference
232 // so either I have to swap the element each time I examine it, or I have to swap
233 // all the elements ahead of time and store them in the font
234
235 const PairInfo* p = pairsSwapped;
236 const PairInfo* tp = (const PairInfo*)(p + (rangeShift/KERN_PAIRINFO_SIZE)); /* rangeshift is in original table bytes */
237 if (key > tp->key) {
238 p = tp;
239 }
240
241 #if DEBUG
242 fprintf(stderr, "binary search for %0.8x\n", key);
243 #endif
244
245 le_uint32 probe = searchRange;
246 while (probe > 1) {
247 probe >>= 1;
248 tp = (const PairInfo*)(p + (probe/KERN_PAIRINFO_SIZE));
249 le_uint32 tkey = tp->key;
250 #if DEBUG
251 fprintf(stdout, " %.3d (%0.8x)\n", (tp - pairsSwapped), tkey);
252 #endif
253 if (tkey <= key) {
254 if (tkey == key) {
255 le_int16 value = SWAPW(tp->value);
256 #if DEBUG
257 fprintf(stdout, "binary found kerning pair %x:%x at %d, value: 0x%x (%g)\n",
258 storage[i-1], storage[i], i, value & 0xffff, font->xUnitsToPoints(value));
259 fflush(stdout);
260 #endif
261 // Have to undo the device transform.
262 // REMIND either find a way to do this only if there is a
263 // device transform, or a faster way, such as moving the
264 // entire kern table up to Java.
265 LEPoint pt;
266 pt.fX = fTable.getFont()->xUnitsToPoints(value);
267 pt.fY = 0;
268
269 fTable.getFont()->getKerningAdjustment(pt);
270 adjust += pt.fX;
271 break;
272 }
273 p = tp;
274 }
275 }
276
277 storage.adjustPosition(i, adjust, 0, success);
278 }
279 storage.adjustPosition(storage.getGlyphCount(), adjust, 0, success);
280 }
281 }
282
283 U_NAMESPACE_END
284