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 "core/svg/SVGAltGlyphDefElement.h"
24
25 #include "SVGNames.h"
26 #include "core/svg/SVGAltGlyphItemElement.h"
27 #include "core/svg/SVGGlyphRefElement.h"
28
29 namespace WebCore {
30
SVGAltGlyphDefElement(Document & document)31 inline SVGAltGlyphDefElement::SVGAltGlyphDefElement(Document& document)
32 : SVGElement(SVGNames::altGlyphDefTag, document)
33 {
34 ScriptWrappable::init(this);
35 }
36
create(Document & document)37 PassRefPtr<SVGAltGlyphDefElement> SVGAltGlyphDefElement::create(Document& document)
38 {
39 return adoptRef(new SVGAltGlyphDefElement(document));
40 }
41
hasValidGlyphElements(Vector<String> & glyphNames) const42 bool SVGAltGlyphDefElement::hasValidGlyphElements(Vector<String>& glyphNames) const
43 {
44 // Spec: http://www.w3.org/TR/SVG/text.html#AltGlyphDefElement
45 // An 'altGlyphDef' can contain either of the following:
46 //
47 // 1. In the simplest case, an 'altGlyphDef' contains one or more 'glyphRef' elements.
48 // Each 'glyphRef' element references a single glyph within a particular font.
49 // If all of the referenced glyphs are available, then these glyphs are rendered
50 // instead of the character(s) inside of the referencing 'altGlyph' element.
51 // If any of the referenced glyphs are unavailable, then the character(s) that are
52 // inside of the 'altGlyph' element are rendered as if there were not an 'altGlyph'
53 // element surrounding those characters.
54 //
55 // 2. In the more complex case, an 'altGlyphDef' contains one or more 'altGlyphItem' elements.
56 // Each 'altGlyphItem' represents a candidate set of substitute glyphs. Each 'altGlyphItem'
57 // contains one or more 'glyphRef' elements. Each 'glyphRef' element references a single
58 // glyph within a particular font. The first 'altGlyphItem' in which all referenced glyphs
59 // are available is chosen. The glyphs referenced from this 'altGlyphItem' are rendered
60 // instead of the character(s) that are inside of the referencing 'altGlyph' element.
61 // If none of the 'altGlyphItem' elements result in a successful match (i.e., none of the
62 // 'altGlyphItem' elements has all of its referenced glyphs available), then the character(s)
63 // that are inside of the 'altGlyph' element are rendered as if there were not an 'altGlyph'
64 // element surrounding those characters.
65 //
66 // The spec doesn't tell how to deal with the mixing of <glyphRef> and <altGlyItem>.
67 // However, we determine content model by the the type of the first appearing element
68 // just like Opera 11 does. After the content model is determined we skip elements
69 // which don't comform to it. For example:
70 // a. <altGlyphDef>
71 // <glyphRef id="g1" />
72 // <altGlyphItem id="i1"> ... </altGlyphItem>
73 // <glyphRef id="g2" />
74 // </altGlyphDef>
75 //
76 // b. <altGlyphDef>
77 // <altGlyphItem id="i1"> ... </altGlyphItem>
78 // <altGlyphItem id="i2"> ... </altGlyphItem>
79 // <glyphRef id="g1" />
80 // <glyphRef id="g2" />
81 // </altGlyphDef>
82 // For a), the content model is 1), so we will use "g1" and "g2" if they are all valid
83 // and "i1" is skipped.
84 // For b), the content model is 2), so we will use <glyphRef> elements contained in
85 // "i1" if they are valid and "g1" and "g2" are skipped.
86
87 // These 2 variables are used to determine content model.
88 bool fountFirstGlyphRef = false;
89 bool foundFirstAltGlyphItem = false;
90
91 for (Node* child = firstChild(); child; child = child->nextSibling()) {
92 if (!foundFirstAltGlyphItem && child->hasTagName(SVGNames::glyphRefTag)) {
93 fountFirstGlyphRef = true;
94 String referredGlyphName;
95
96 if (toSVGGlyphRefElement(child)->hasValidGlyphElement(referredGlyphName))
97 glyphNames.append(referredGlyphName);
98 else {
99 // As the spec says "If any of the referenced glyphs are unavailable,
100 // then the character(s) that are inside of the 'altGlyph' element are
101 // rendered as if there were not an 'altGlyph' element surrounding
102 // those characters.".
103 glyphNames.clear();
104 return false;
105 }
106 } else if (!fountFirstGlyphRef && child->hasTagName(SVGNames::altGlyphItemTag)) {
107 foundFirstAltGlyphItem = true;
108 Vector<String> referredGlyphNames;
109
110 // As the spec says "The first 'altGlyphItem' in which all referenced glyphs
111 // are available is chosen."
112 if (static_cast<SVGAltGlyphItemElement*>(child)->hasValidGlyphElements(glyphNames) && !glyphNames.isEmpty())
113 return true;
114 }
115 }
116 return !glyphNames.isEmpty();
117 }
118
119 }
120
121 #endif
122