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 "SVGFontElement.h"
26
27#include "Document.h"
28#include "Font.h"
29#include "GlyphPageTreeNode.h"
30#include "SVGGlyphElement.h"
31#include "SVGHKernElement.h"
32#include "SVGMissingGlyphElement.h"
33#include "SVGNames.h"
34#include "SVGVKernElement.h"
35#include <wtf/ASCIICType.h>
36
37namespace WebCore {
38
39// Animated property definitions
40DEFINE_ANIMATED_BOOLEAN(SVGFontElement, SVGNames::externalResourcesRequiredAttr, ExternalResourcesRequired, externalResourcesRequired)
41
42BEGIN_REGISTER_ANIMATED_PROPERTIES(SVGFontElement)
43    REGISTER_LOCAL_ANIMATED_PROPERTY(externalResourcesRequired)
44    REGISTER_PARENT_ANIMATED_PROPERTIES(SVGStyledElement)
45END_REGISTER_ANIMATED_PROPERTIES
46
47inline SVGFontElement::SVGFontElement(const QualifiedName& tagName, Document* document)
48    : SVGStyledElement(tagName, document)
49    , m_missingGlyph(0)
50    , m_isGlyphCacheValid(false)
51{
52    ASSERT(hasTagName(SVGNames::fontTag));
53    registerAnimatedPropertiesForSVGFontElement();
54}
55
56PassRefPtr<SVGFontElement> SVGFontElement::create(const QualifiedName& tagName, Document* document)
57{
58    return adoptRef(new SVGFontElement(tagName, document));
59}
60
61void SVGFontElement::invalidateGlyphCache()
62{
63    if (m_isGlyphCacheValid) {
64        m_glyphMap.clear();
65        m_horizontalKerningPairs.clear();
66        m_verticalKerningPairs.clear();
67    }
68    m_isGlyphCacheValid = false;
69}
70
71SVGMissingGlyphElement* SVGFontElement::firstMissingGlyphElement() const
72{
73    for (Node* child = firstChild(); child; child = child->nextSibling()) {
74        if (child->hasTagName(SVGNames::missing_glyphTag))
75            return static_cast<SVGMissingGlyphElement*>(child);
76    }
77
78    return 0;
79}
80
81void SVGFontElement::registerLigaturesInGlyphCache(Vector<String>& ligatures)
82{
83    ASSERT(!ligatures.isEmpty());
84
85    // Register each character of a ligature in the map, if not present.
86    // Eg. If only a "fi" ligature is present, but not "f" and "i", the
87    // GlyphPage will not contain any entries for "f" and "i", so the
88    // SVGFont is not used to render the text "fi1234". Register an
89    // empty SVGGlyph with the character, so the SVG Font will be used
90    // to render the text. If someone tries to render "f2" the SVG Font
91    // will not be able to find a glyph for "f", but handles the fallback
92    // character substitution properly through glyphDataForCharacter().
93    Vector<SVGGlyph> glyphs;
94    size_t ligaturesSize = ligatures.size();
95    for (size_t i = 0; i < ligaturesSize; ++i) {
96        const String& unicode = ligatures[i];
97
98        unsigned unicodeLength = unicode.length();
99        ASSERT(unicodeLength > 1);
100
101        const UChar* characters = unicode.characters();
102        for (unsigned i = 0; i < unicodeLength; ++i) {
103            String lookupString(characters + i, 1);
104            m_glyphMap.collectGlyphsForString(lookupString, glyphs);
105            if (!glyphs.isEmpty()) {
106                glyphs.clear();
107                continue;
108            }
109
110            // This glyph is never meant to be used for rendering, only as identifier as a part of a ligature.
111            SVGGlyph newGlyphPart;
112            newGlyphPart.isPartOfLigature = true;
113            m_glyphMap.addGlyph(String(), lookupString, newGlyphPart);
114        }
115    }
116}
117
118void SVGFontElement::ensureGlyphCache()
119{
120    if (m_isGlyphCacheValid)
121        return;
122
123    SVGMissingGlyphElement* firstMissingGlyphElement = 0;
124    Vector<String> ligatures;
125    for (Node* child = firstChild(); child; child = child->nextSibling()) {
126        if (child->hasTagName(SVGNames::glyphTag)) {
127            SVGGlyphElement* glyph = static_cast<SVGGlyphElement*>(child);
128            AtomicString unicode = glyph->fastGetAttribute(SVGNames::unicodeAttr);
129            AtomicString glyphId = glyph->getIdAttribute();
130            if (glyphId.isEmpty() && unicode.isEmpty())
131                continue;
132
133            m_glyphMap.addGlyph(glyphId, unicode, glyph->buildGlyphIdentifier());
134
135            // Register ligatures, if needed, don't mix up with surrogate pairs though!
136            if (unicode.length() > 1 && !U16_IS_SURROGATE(unicode[0]))
137                ligatures.append(unicode.string());
138        } else if (child->hasTagName(SVGNames::hkernTag)) {
139            SVGHKernElement* hkern = static_cast<SVGHKernElement*>(child);
140            hkern->buildHorizontalKerningPair(m_horizontalKerningPairs);
141        } else if (child->hasTagName(SVGNames::vkernTag)) {
142            SVGVKernElement* vkern = static_cast<SVGVKernElement*>(child);
143            vkern->buildVerticalKerningPair(m_verticalKerningPairs);
144        } else if (child->hasTagName(SVGNames::missing_glyphTag) && !firstMissingGlyphElement)
145            firstMissingGlyphElement = static_cast<SVGMissingGlyphElement*>(child);
146    }
147
148    // Register each character of each ligature, if needed.
149    if (!ligatures.isEmpty())
150        registerLigaturesInGlyphCache(ligatures);
151
152    // Register missing-glyph element, if present.
153    if (firstMissingGlyphElement) {
154        SVGGlyph svgGlyph = SVGGlyphElement::buildGenericGlyphIdentifier(firstMissingGlyphElement);
155        m_glyphMap.appendToGlyphTable(svgGlyph);
156        m_missingGlyph = svgGlyph.tableEntry;
157        ASSERT(m_missingGlyph > 0);
158    }
159
160    m_isGlyphCacheValid = true;
161}
162
163static bool stringMatchesUnicodeRange(const String& unicodeString, const UnicodeRanges& ranges, const HashSet<String>& unicodeValues)
164{
165    if (unicodeString.isEmpty())
166        return false;
167
168    if (!ranges.isEmpty()) {
169        UChar firstChar = unicodeString[0];
170        const UnicodeRanges::const_iterator end = ranges.end();
171        for (UnicodeRanges::const_iterator it = ranges.begin(); it != end; ++it) {
172            if (firstChar >= it->first && firstChar <= it->second)
173                return true;
174        }
175    }
176
177    if (!unicodeValues.isEmpty())
178        return unicodeValues.contains(unicodeString);
179
180    return false;
181}
182
183static bool stringMatchesGlyphName(const String& glyphName, const HashSet<String>& glyphValues)
184{
185    if (glyphName.isEmpty())
186        return false;
187
188    if (!glyphValues.isEmpty())
189        return glyphValues.contains(glyphName);
190
191    return false;
192}
193
194static bool matches(const String& u1, const String& g1, const String& u2, const String& g2, const SVGKerningPair& kerningPair)
195{
196    if (!stringMatchesUnicodeRange(u1, kerningPair.unicodeRange1, kerningPair.unicodeName1)
197        && !stringMatchesGlyphName(g1, kerningPair.glyphName1))
198        return false;
199
200    if (!stringMatchesUnicodeRange(u2, kerningPair.unicodeRange2, kerningPair.unicodeName2)
201        && !stringMatchesGlyphName(g2, kerningPair.glyphName2))
202        return false;
203
204    return true;
205}
206
207static float kerningForPairOfStringsAndGlyphs(const KerningPairVector& kerningPairs, const String& u1, const String& g1, const String& u2, const String& g2)
208{
209    KerningPairVector::const_iterator it = kerningPairs.end() - 1;
210    const KerningPairVector::const_iterator begin = kerningPairs.begin() - 1;
211    for (; it != begin; --it) {
212        if (matches(u1, g1, u2, g2, *it))
213            return it->kerning;
214    }
215
216    return 0;
217}
218
219float SVGFontElement::horizontalKerningForPairOfStringsAndGlyphs(const String& u1, const String& g1, const String& u2, const String& g2) const
220{
221    if (m_horizontalKerningPairs.isEmpty())
222        return 0;
223
224    return kerningForPairOfStringsAndGlyphs(m_horizontalKerningPairs, u1, g1, u2, g2);
225}
226
227float SVGFontElement::verticalKerningForPairOfStringsAndGlyphs(const String& u1, const String& g1, const String& u2, const String& g2) const
228{
229    if (m_verticalKerningPairs.isEmpty())
230        return 0;
231
232    return kerningForPairOfStringsAndGlyphs(m_verticalKerningPairs, u1, g1, u2, g2);
233}
234
235void SVGFontElement::collectGlyphsForString(const String& string, Vector<SVGGlyph>& glyphs)
236{
237    ensureGlyphCache();
238    m_glyphMap.collectGlyphsForString(string, glyphs);
239}
240
241void SVGFontElement::collectGlyphsForGlyphName(const String& glyphName, Vector<SVGGlyph>& glyphs)
242{
243    ensureGlyphCache();
244    // FIXME: We only support glyphName -> single glyph mapping so far.
245    glyphs.append(m_glyphMap.glyphIdentifierForGlyphName(glyphName));
246}
247
248SVGGlyph SVGFontElement::svgGlyphForGlyph(Glyph glyph)
249{
250    ensureGlyphCache();
251    return m_glyphMap.svgGlyphForGlyph(glyph);
252}
253
254Glyph SVGFontElement::missingGlyph()
255{
256    ensureGlyphCache();
257    return m_missingGlyph;
258}
259
260}
261
262#endif // ENABLE(SVG_FONTS)
263