1/*
2 * Copyright (C) 2011 Leo Yang <leoyang@webkit.org>
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
13 *
14 * You should have received a copy of the GNU Library General Public License
15 * along with this library; see the file COPYING.LIB. If not, write to
16 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
17 * Boston, MA 02110-1301, USA.
18 */
19
20#include "config.h"
21
22#if ENABLE(SVG_FONTS)
23#include "SVGAltGlyphDefElement.h"
24
25#include "ElementIterator.h"
26#include "SVGAltGlyphItemElement.h"
27#include "SVGGlyphRefElement.h"
28#include "SVGNames.h"
29#include <wtf/IsoMallocInlines.h>
30
31namespace WebCore {
32
33WTF_MAKE_ISO_ALLOCATED_IMPL(SVGAltGlyphDefElement);
34
35inline SVGAltGlyphDefElement::SVGAltGlyphDefElement(const QualifiedName& tagName, Document& document)
36 : SVGElement(tagName, document)
37{
38 ASSERT(hasTagName(SVGNames::altGlyphDefTag));
39}
40
41Ref<SVGAltGlyphDefElement> SVGAltGlyphDefElement::create(const QualifiedName& tagName, Document& document)
42{
43 return adoptRef(*new SVGAltGlyphDefElement(tagName, document));
44}
45
46bool SVGAltGlyphDefElement::hasValidGlyphElements(Vector<String>& glyphNames) const
47{
48 // Spec: http://www.w3.org/TR/SVG/text.html#AltGlyphDefElement
49 // An 'altGlyphDef' can contain either of the following:
50 //
51 // 1. In the simplest case, an 'altGlyphDef' contains one or more 'glyphRef' elements.
52 // Each 'glyphRef' element references a single glyph within a particular font.
53 // If all of the referenced glyphs are available, then these glyphs are rendered
54 // instead of the character(s) inside of the referencing 'altGlyph' element.
55 // If any of the referenced glyphs are unavailable, then the character(s) that are
56 // inside of the 'altGlyph' element are rendered as if there were not an 'altGlyph'
57 // element surrounding those characters.
58 //
59 // 2. In the more complex case, an 'altGlyphDef' contains one or more 'altGlyphItem' elements.
60 // Each 'altGlyphItem' represents a candidate set of substitute glyphs. Each 'altGlyphItem'
61 // contains one or more 'glyphRef' elements. Each 'glyphRef' element references a single
62 // glyph within a particular font. The first 'altGlyphItem' in which all referenced glyphs
63 // are available is chosen. The glyphs referenced from this 'altGlyphItem' are rendered
64 // instead of the character(s) that are inside of the referencing 'altGlyph' element.
65 // If none of the 'altGlyphItem' elements result in a successful match (i.e., none of the
66 // 'altGlyphItem' elements has all of its referenced glyphs available), then the character(s)
67 // that are inside of the 'altGlyph' element are rendered as if there were not an 'altGlyph'
68 // element surrounding those characters.
69 //
70 // The spec doesn't tell how to deal with the mixing of <glyphRef> and <altGlyItem>.
71 // However, we determine content model by the type of the first appearing element
72 // just like Opera 11 does. After the content model is determined we skip elements
73 // which don't comform to it. For example:
74 // a. <altGlyphDef>
75 // <glyphRef id="g1" />
76 // <altGlyphItem id="i1"> ... </altGlyphItem>
77 // <glyphRef id="g2" />
78 // </altGlyphDef>
79 //
80 // b. <altGlyphDef>
81 // <altGlyphItem id="i1"> ... </altGlyphItem>
82 // <altGlyphItem id="i2"> ... </altGlyphItem>
83 // <glyphRef id="g1" />
84 // <glyphRef id="g2" />
85 // </altGlyphDef>
86 // For a), the content model is 1), so we will use "g1" and "g2" if they are all valid
87 // and "i1" is skipped.
88 // For b), the content model is 2), so we will use <glyphRef> elements contained in
89 // "i1" if they are valid and "g1" and "g2" are skipped.
90
91 // These 2 variables are used to determine content model.
92 bool fountFirstGlyphRef = false;
93 bool foundFirstAltGlyphItem = false;
94
95 for (auto& child : childrenOfType<SVGElement>(*this)) {
96 if (!foundFirstAltGlyphItem && is<SVGGlyphRefElement>(child)) {
97 fountFirstGlyphRef = true;
98 String referredGlyphName;
99
100 if (downcast<SVGGlyphRefElement>(child).hasValidGlyphElement(referredGlyphName))
101 glyphNames.append(referredGlyphName);
102 else {
103 // As the spec says "If any of the referenced glyphs are unavailable,
104 // then the character(s) that are inside of the 'altGlyph' element are
105 // rendered as if there were not an 'altGlyph' element surrounding
106 // those characters.".
107 glyphNames.clear();
108 return false;
109 }
110 } else if (!fountFirstGlyphRef && is<SVGAltGlyphItemElement>(child)) {
111 foundFirstAltGlyphItem = true;
112
113 // As the spec says "The first 'altGlyphItem' in which all referenced glyphs
114 // are available is chosen."
115 if (downcast<SVGAltGlyphItemElement>(child).hasValidGlyphElements(glyphNames) && !glyphNames.isEmpty())
116 return true;
117 }
118 }
119 return !glyphNames.isEmpty();
120}
121
122}
123
124#endif
125