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/frame/UseCounter.h"
28#include "core/svg/SVGGlyphElement.h"
29#include "core/svg/SVGHKernElement.h"
30#include "core/svg/SVGMissingGlyphElement.h"
31#include "core/svg/SVGVKernElement.h"
32#include "wtf/ASCIICType.h"
33
34namespace WebCore {
35
36// Animated property definitions
37DEFINE_ANIMATED_BOOLEAN(SVGFontElement, SVGNames::externalResourcesRequiredAttr, ExternalResourcesRequired, externalResourcesRequired)
38
39BEGIN_REGISTER_ANIMATED_PROPERTIES(SVGFontElement)
40    REGISTER_LOCAL_ANIMATED_PROPERTY(externalResourcesRequired)
41    REGISTER_PARENT_ANIMATED_PROPERTIES(SVGElement)
42END_REGISTER_ANIMATED_PROPERTIES
43
44inline SVGFontElement::SVGFontElement(Document& document)
45    : SVGElement(SVGNames::fontTag, document)
46    , m_missingGlyph(0)
47    , m_isGlyphCacheValid(false)
48{
49    ScriptWrappable::init(this);
50    registerAnimatedPropertiesForSVGFontElement();
51
52    UseCounter::count(document, UseCounter::SVGFontElement);
53}
54
55PassRefPtr<SVGFontElement> SVGFontElement::create(Document& document)
56{
57    return adoptRef(new SVGFontElement(document));
58}
59
60void SVGFontElement::invalidateGlyphCache()
61{
62    if (m_isGlyphCacheValid) {
63        m_glyphMap.clear();
64        m_horizontalKerningPairs.clear();
65        m_verticalKerningPairs.clear();
66    }
67    m_isGlyphCacheValid = false;
68}
69
70SVGMissingGlyphElement* SVGFontElement::firstMissingGlyphElement() const
71{
72    for (Node* child = firstChild(); child; child = child->nextSibling()) {
73        if (child->hasTagName(SVGNames::missing_glyphTag))
74            return toSVGMissingGlyphElement(child);
75    }
76
77    return 0;
78}
79
80void SVGFontElement::registerLigaturesInGlyphCache(Vector<String>& ligatures)
81{
82    ASSERT(!ligatures.isEmpty());
83
84    // Register each character of a ligature in the map, if not present.
85    // Eg. If only a "fi" ligature is present, but not "f" and "i", the
86    // GlyphPage will not contain any entries for "f" and "i", so the
87    // SVGFont is not used to render the text "fi1234". Register an
88    // empty SVGGlyph with the character, so the SVG Font will be used
89    // to render the text. If someone tries to render "f2" the SVG Font
90    // will not be able to find a glyph for "f", but handles the fallback
91    // character substitution properly through glyphDataForCharacter().
92    Vector<SVGGlyph> glyphs;
93    size_t ligaturesSize = ligatures.size();
94    for (size_t i = 0; i < ligaturesSize; ++i) {
95        const String& unicode = ligatures[i];
96
97        unsigned unicodeLength = unicode.length();
98        ASSERT(unicodeLength > 1);
99
100        for (unsigned i = 0; i < unicodeLength; ++i) {
101            String lookupString = unicode.substring(i, 1);
102            m_glyphMap.collectGlyphsForString(lookupString, glyphs);
103            if (!glyphs.isEmpty()) {
104                glyphs.clear();
105                continue;
106            }
107
108            // This glyph is never meant to be used for rendering, only as identifier as a part of a ligature.
109            SVGGlyph newGlyphPart;
110            newGlyphPart.isPartOfLigature = true;
111            m_glyphMap.addGlyph(String(), lookupString, newGlyphPart);
112        }
113    }
114}
115
116void SVGFontElement::ensureGlyphCache()
117{
118    if (m_isGlyphCacheValid)
119        return;
120
121    SVGMissingGlyphElement* firstMissingGlyphElement = 0;
122    Vector<String> ligatures;
123    for (Node* child = firstChild(); child; child = child->nextSibling()) {
124        if (child->hasTagName(SVGNames::glyphTag)) {
125            SVGGlyphElement* glyph = toSVGGlyphElement(child);
126            AtomicString unicode = glyph->fastGetAttribute(SVGNames::unicodeAttr);
127            AtomicString glyphId = glyph->getIdAttribute();
128            if (glyphId.isEmpty() && unicode.isEmpty())
129                continue;
130
131            m_glyphMap.addGlyph(glyphId, unicode, glyph->buildGlyphIdentifier());
132
133            // Register ligatures, if needed, don't mix up with surrogate pairs though!
134            if (unicode.length() > 1 && !U16_IS_SURROGATE(unicode[0]))
135                ligatures.append(unicode.string());
136        } else if (child->hasTagName(SVGNames::hkernTag)) {
137            toSVGHKernElement(child)->buildHorizontalKerningPair(m_horizontalKerningPairs);
138        } else if (child->hasTagName(SVGNames::vkernTag)) {
139            toSVGVKernElement(child)->buildVerticalKerningPair(m_verticalKerningPairs);
140        } else if (child->hasTagName(SVGNames::missing_glyphTag) && !firstMissingGlyphElement) {
141            firstMissingGlyphElement = toSVGMissingGlyphElement(child);
142        }
143    }
144
145    // Register each character of each ligature, if needed.
146    if (!ligatures.isEmpty())
147        registerLigaturesInGlyphCache(ligatures);
148
149    // Register missing-glyph element, if present.
150    if (firstMissingGlyphElement) {
151        SVGGlyph svgGlyph = SVGGlyphElement::buildGenericGlyphIdentifier(firstMissingGlyphElement);
152        m_glyphMap.appendToGlyphTable(svgGlyph);
153        m_missingGlyph = svgGlyph.tableEntry;
154        ASSERT(m_missingGlyph > 0);
155    }
156
157    m_isGlyphCacheValid = true;
158}
159
160static bool stringMatchesUnicodeRange(const String& unicodeString, const UnicodeRanges& ranges, const HashSet<String>& unicodeValues)
161{
162    if (unicodeString.isEmpty())
163        return false;
164
165    if (!ranges.isEmpty()) {
166        UChar firstChar = unicodeString[0];
167        const UnicodeRanges::const_iterator end = ranges.end();
168        for (UnicodeRanges::const_iterator it = ranges.begin(); it != end; ++it) {
169            if (firstChar >= it->first && firstChar <= it->second)
170                return true;
171        }
172    }
173
174    if (!unicodeValues.isEmpty())
175        return unicodeValues.contains(unicodeString);
176
177    return false;
178}
179
180static bool stringMatchesGlyphName(const String& glyphName, const HashSet<String>& glyphValues)
181{
182    if (glyphName.isEmpty())
183        return false;
184
185    if (!glyphValues.isEmpty())
186        return glyphValues.contains(glyphName);
187
188    return false;
189}
190
191static bool matches(const String& u1, const String& g1, const String& u2, const String& g2, const SVGKerningPair& kerningPair)
192{
193    if (!stringMatchesUnicodeRange(u1, kerningPair.unicodeRange1, kerningPair.unicodeName1)
194        && !stringMatchesGlyphName(g1, kerningPair.glyphName1))
195        return false;
196
197    if (!stringMatchesUnicodeRange(u2, kerningPair.unicodeRange2, kerningPair.unicodeName2)
198        && !stringMatchesGlyphName(g2, kerningPair.glyphName2))
199        return false;
200
201    return true;
202}
203
204static float kerningForPairOfStringsAndGlyphs(const KerningPairVector& kerningPairs, const String& u1, const String& g1, const String& u2, const String& g2)
205{
206    KerningPairVector::const_iterator it = kerningPairs.end() - 1;
207    const KerningPairVector::const_iterator begin = kerningPairs.begin() - 1;
208    for (; it != begin; --it) {
209        if (matches(u1, g1, u2, g2, *it))
210            return it->kerning;
211    }
212
213    return 0;
214}
215
216float SVGFontElement::horizontalKerningForPairOfStringsAndGlyphs(const String& u1, const String& g1, const String& u2, const String& g2) const
217{
218    if (m_horizontalKerningPairs.isEmpty())
219        return 0;
220
221    return kerningForPairOfStringsAndGlyphs(m_horizontalKerningPairs, u1, g1, u2, g2);
222}
223
224float SVGFontElement::verticalKerningForPairOfStringsAndGlyphs(const String& u1, const String& g1, const String& u2, const String& g2) const
225{
226    if (m_verticalKerningPairs.isEmpty())
227        return 0;
228
229    return kerningForPairOfStringsAndGlyphs(m_verticalKerningPairs, u1, g1, u2, g2);
230}
231
232void SVGFontElement::collectGlyphsForString(const String& string, Vector<SVGGlyph>& glyphs)
233{
234    ensureGlyphCache();
235    m_glyphMap.collectGlyphsForString(string, glyphs);
236}
237
238void SVGFontElement::collectGlyphsForGlyphName(const String& glyphName, Vector<SVGGlyph>& glyphs)
239{
240    ensureGlyphCache();
241    // FIXME: We only support glyphName -> single glyph mapping so far.
242    glyphs.append(m_glyphMap.glyphIdentifierForGlyphName(glyphName));
243}
244
245SVGGlyph SVGFontElement::svgGlyphForGlyph(Glyph glyph)
246{
247    ensureGlyphCache();
248    return m_glyphMap.svgGlyphForGlyph(glyph);
249}
250
251Glyph SVGFontElement::missingGlyph()
252{
253    ensureGlyphCache();
254    return m_missingGlyph;
255}
256
257}
258
259#endif // ENABLE(SVG_FONTS)
260