1 /*
2 * Copyright (C) 2007 Eric Seidel <eric@webkit.org>
3 * Copyright (C) 2007 Nikolas Zimmermann <zimmermann@kde.org>
4 * Copyright (C) Research In Motion Limited 2010. All rights reserved.
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Library General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Library General Public License for more details.
15 *
16 * You should have received a copy of the GNU Library General Public License
17 * along with this library; see the file COPYING.LIB. If not, write to
18 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
19 * Boston, MA 02110-1301, USA.
20 */
21
22 #include "config.h"
23
24 #if ENABLE(SVG_FONTS)
25 #include "core/svg/SVGFontElement.h"
26
27 #include "core/dom/ElementTraversal.h"
28 #include "core/frame/UseCounter.h"
29 #include "core/svg/SVGGlyphElement.h"
30 #include "core/svg/SVGHKernElement.h"
31 #include "core/svg/SVGMissingGlyphElement.h"
32 #include "core/svg/SVGVKernElement.h"
33 #include "wtf/ASCIICType.h"
34
35 namespace WebCore {
36
SVGFontElement(Document & document)37 inline SVGFontElement::SVGFontElement(Document& document)
38 : SVGElement(SVGNames::fontTag, document)
39 , m_missingGlyph(0)
40 , m_isGlyphCacheValid(false)
41 {
42 ScriptWrappable::init(this);
43
44 UseCounter::count(document, UseCounter::SVGFontElement);
45 }
46
DEFINE_NODE_FACTORY(SVGFontElement)47 DEFINE_NODE_FACTORY(SVGFontElement)
48
49 void SVGFontElement::invalidateGlyphCache()
50 {
51 if (m_isGlyphCacheValid) {
52 m_glyphMap.clear();
53 m_horizontalKerningTable.clear();
54 m_verticalKerningTable.clear();
55 }
56 m_isGlyphCacheValid = false;
57 }
58
registerLigaturesInGlyphCache(Vector<String> & ligatures)59 void SVGFontElement::registerLigaturesInGlyphCache(Vector<String>& ligatures)
60 {
61 ASSERT(!ligatures.isEmpty());
62
63 // Register each character of a ligature in the map, if not present.
64 // Eg. If only a "fi" ligature is present, but not "f" and "i", the
65 // GlyphPage will not contain any entries for "f" and "i", so the
66 // SVGFont is not used to render the text "fi1234". Register an
67 // empty SVGGlyph with the character, so the SVG Font will be used
68 // to render the text. If someone tries to render "f2" the SVG Font
69 // will not be able to find a glyph for "f", but handles the fallback
70 // character substitution properly through glyphDataForCharacter().
71 Vector<SVGGlyph> glyphs;
72 size_t ligaturesSize = ligatures.size();
73 for (size_t i = 0; i < ligaturesSize; ++i) {
74 const String& unicode = ligatures[i];
75
76 unsigned unicodeLength = unicode.length();
77 ASSERT(unicodeLength > 1);
78
79 for (unsigned i = 0; i < unicodeLength; ++i) {
80 String lookupString = unicode.substring(i, 1);
81 m_glyphMap.collectGlyphsForString(lookupString, glyphs);
82 if (!glyphs.isEmpty()) {
83 glyphs.clear();
84 continue;
85 }
86
87 // This glyph is never meant to be used for rendering, only as identifier as a part of a ligature.
88 SVGGlyph newGlyphPart;
89 newGlyphPart.isPartOfLigature = true;
90 m_glyphMap.addGlyph(String(), lookupString, newGlyphPart);
91 }
92 }
93 }
94
makeKerningPairKey(Glyph glyphId1,Glyph glyphId2)95 static inline KerningPairKey makeKerningPairKey(Glyph glyphId1, Glyph glyphId2)
96 {
97 return glyphId1 << 16 | glyphId2;
98 }
99
buildGlyphList(const UnicodeRanges & unicodeRanges,const HashSet<String> & unicodeNames,const HashSet<String> & glyphNames) const100 Vector<SVGGlyph> SVGFontElement::buildGlyphList(const UnicodeRanges& unicodeRanges, const HashSet<String>& unicodeNames, const HashSet<String>& glyphNames) const
101 {
102 Vector<SVGGlyph> glyphs;
103 if (!unicodeRanges.isEmpty()) {
104 const UnicodeRanges::const_iterator end = unicodeRanges.end();
105 for (UnicodeRanges::const_iterator it = unicodeRanges.begin(); it != end; ++it)
106 m_glyphMap.collectGlyphsForUnicodeRange(*it, glyphs);
107 }
108 if (!unicodeNames.isEmpty()) {
109 const HashSet<String>::const_iterator end = unicodeNames.end();
110 for (HashSet<String>::const_iterator it = unicodeNames.begin(); it != end; ++it)
111 m_glyphMap.collectGlyphsForStringExact(*it, glyphs);
112 }
113 if (!glyphNames.isEmpty()) {
114 const HashSet<String>::const_iterator end = glyphNames.end();
115 for (HashSet<String>::const_iterator it = glyphNames.begin(); it != end; ++it) {
116 const SVGGlyph& glyph = m_glyphMap.glyphIdentifierForGlyphName(*it);
117 if (glyph.tableEntry)
118 glyphs.append(glyph);
119 }
120 }
121 return glyphs;
122 }
123
addPairsToKerningTable(const SVGKerningPair & kerningPair,KerningTable & kerningTable)124 void SVGFontElement::addPairsToKerningTable(const SVGKerningPair& kerningPair, KerningTable& kerningTable)
125 {
126 Vector<SVGGlyph> glyphsLhs = buildGlyphList(kerningPair.unicodeRange1, kerningPair.unicodeName1, kerningPair.glyphName1);
127 Vector<SVGGlyph> glyphsRhs = buildGlyphList(kerningPair.unicodeRange2, kerningPair.unicodeName2, kerningPair.glyphName2);
128 if (glyphsLhs.isEmpty() || glyphsRhs.isEmpty())
129 return;
130 size_t glyphsLhsSize = glyphsLhs.size();
131 size_t glyphsRhsSize = glyphsRhs.size();
132 // Enumerate all the valid kerning pairs, and add them to the table.
133 for (size_t lhsIndex = 0; lhsIndex < glyphsLhsSize; ++lhsIndex) {
134 for (size_t rhsIndex = 0; rhsIndex < glyphsRhsSize; ++rhsIndex) {
135 Glyph glyph1 = glyphsLhs[lhsIndex].tableEntry;
136 Glyph glyph2 = glyphsRhs[rhsIndex].tableEntry;
137 ASSERT(glyph1 && glyph2);
138 kerningTable.add(makeKerningPairKey(glyph1, glyph2), kerningPair.kerning);
139 }
140 }
141 }
142
buildKerningTable(const KerningPairVector & kerningPairs,KerningTable & kerningTable)143 void SVGFontElement::buildKerningTable(const KerningPairVector& kerningPairs, KerningTable& kerningTable)
144 {
145 size_t kerningPairsSize = kerningPairs.size();
146 for (size_t i = 0; i < kerningPairsSize; ++i)
147 addPairsToKerningTable(kerningPairs[i], kerningTable);
148 }
149
ensureGlyphCache()150 void SVGFontElement::ensureGlyphCache()
151 {
152 if (m_isGlyphCacheValid)
153 return;
154
155 KerningPairVector horizontalKerningPairs;
156 KerningPairVector verticalKerningPairs;
157
158 SVGMissingGlyphElement* firstMissingGlyphElement = 0;
159 Vector<String> ligatures;
160 for (SVGElement* element = Traversal<SVGElement>::firstChild(*this); element; element = Traversal<SVGElement>::nextSibling(*element)) {
161 if (isSVGGlyphElement(*element)) {
162 SVGGlyphElement& glyph = toSVGGlyphElement(*element);
163 AtomicString unicode = glyph.fastGetAttribute(SVGNames::unicodeAttr);
164 AtomicString glyphId = glyph.getIdAttribute();
165 if (glyphId.isEmpty() && unicode.isEmpty())
166 continue;
167
168 m_glyphMap.addGlyph(glyphId, unicode, glyph.buildGlyphIdentifier());
169
170 // Register ligatures, if needed, don't mix up with surrogate pairs though!
171 if (unicode.length() > 1 && !U16_IS_SURROGATE(unicode[0]))
172 ligatures.append(unicode.string());
173 } else if (isSVGHKernElement(*element)) {
174 toSVGHKernElement(*element).buildHorizontalKerningPair(horizontalKerningPairs);
175 } else if (isSVGVKernElement(*element)) {
176 toSVGVKernElement(*element).buildVerticalKerningPair(verticalKerningPairs);
177 } else if (isSVGMissingGlyphElement(*element) && !firstMissingGlyphElement) {
178 firstMissingGlyphElement = toSVGMissingGlyphElement(element);
179 }
180 }
181
182 // Build the kerning tables.
183 buildKerningTable(horizontalKerningPairs, m_horizontalKerningTable);
184 buildKerningTable(verticalKerningPairs, m_verticalKerningTable);
185
186 // The glyph-name->glyph-id map won't be needed/used after having built the kerning table(s).
187 m_glyphMap.dropNamedGlyphMap();
188
189 // Register each character of each ligature, if needed.
190 if (!ligatures.isEmpty())
191 registerLigaturesInGlyphCache(ligatures);
192
193 // Register missing-glyph element, if present.
194 if (firstMissingGlyphElement) {
195 SVGGlyph svgGlyph = SVGGlyphElement::buildGenericGlyphIdentifier(firstMissingGlyphElement);
196 m_glyphMap.appendToGlyphTable(svgGlyph);
197 m_missingGlyph = svgGlyph.tableEntry;
198 ASSERT(m_missingGlyph > 0);
199 }
200
201 m_isGlyphCacheValid = true;
202 }
203
kerningForPairOfGlyphs(const KerningTable & kerningTable,Glyph glyphId1,Glyph glyphId2)204 static float kerningForPairOfGlyphs(const KerningTable& kerningTable, Glyph glyphId1, Glyph glyphId2)
205 {
206 KerningTable::const_iterator result = kerningTable.find(makeKerningPairKey(glyphId1, glyphId2));
207 if (result != kerningTable.end())
208 return result->value;
209
210 return 0;
211 }
212
horizontalKerningForPairOfGlyphs(Glyph glyphId1,Glyph glyphId2) const213 float SVGFontElement::horizontalKerningForPairOfGlyphs(Glyph glyphId1, Glyph glyphId2) const
214 {
215 if (m_horizontalKerningTable.isEmpty())
216 return 0;
217
218 return kerningForPairOfGlyphs(m_horizontalKerningTable, glyphId1, glyphId2);
219 }
220
verticalKerningForPairOfGlyphs(Glyph glyphId1,Glyph glyphId2) const221 float SVGFontElement::verticalKerningForPairOfGlyphs(Glyph glyphId1, Glyph glyphId2) const
222 {
223 if (m_verticalKerningTable.isEmpty())
224 return 0;
225
226 return kerningForPairOfGlyphs(m_verticalKerningTable, glyphId1, glyphId2);
227 }
228
collectGlyphsForString(const String & string,Vector<SVGGlyph> & glyphs)229 void SVGFontElement::collectGlyphsForString(const String& string, Vector<SVGGlyph>& glyphs)
230 {
231 ensureGlyphCache();
232 m_glyphMap.collectGlyphsForString(string, glyphs);
233 }
234
collectGlyphsForAltGlyphReference(const String & glyphIdentifier,Vector<SVGGlyph> & glyphs)235 void SVGFontElement::collectGlyphsForAltGlyphReference(const String& glyphIdentifier, Vector<SVGGlyph>& glyphs)
236 {
237 ensureGlyphCache();
238 // FIXME: We only support glyphName -> single glyph mapping so far.
239 glyphs.append(m_glyphMap.glyphIdentifierForAltGlyphReference(glyphIdentifier));
240 }
241
svgGlyphForGlyph(Glyph glyph)242 SVGGlyph SVGFontElement::svgGlyphForGlyph(Glyph glyph)
243 {
244 ensureGlyphCache();
245 return m_glyphMap.svgGlyphForGlyph(glyph);
246 }
247
missingGlyph()248 Glyph SVGFontElement::missingGlyph()
249 {
250 ensureGlyphCache();
251 return m_missingGlyph;
252 }
253
254 }
255
256 #endif // ENABLE(SVG_FONTS)
257