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SVGAltGlyphDefElement.cpp
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120 lines (108 loc) · 5.41 KB
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/*
* Copyright (C) 2011 Leo Yang <leoyang@webkit.org>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#include "config.h"
#include "SVGAltGlyphDefElement.h"
#include "ElementIterator.h"
#include "SVGAltGlyphItemElement.h"
#include "SVGGlyphRefElement.h"
#include "SVGNames.h"
#include <wtf/IsoMallocInlines.h>
namespace WebCore {
WTF_MAKE_ISO_ALLOCATED_IMPL(SVGAltGlyphDefElement);
inline SVGAltGlyphDefElement::SVGAltGlyphDefElement(const QualifiedName& tagName, Document& document)
: SVGElement(tagName, document)
{
ASSERT(hasTagName(SVGNames::altGlyphDefTag));
}
Ref<SVGAltGlyphDefElement> SVGAltGlyphDefElement::create(const QualifiedName& tagName, Document& document)
{
return adoptRef(*new SVGAltGlyphDefElement(tagName, document));
}
bool SVGAltGlyphDefElement::hasValidGlyphElements(Vector<String>& glyphNames) const
{
// Spec: http://www.w3.org/TR/SVG/text.html#AltGlyphDefElement
// An 'altGlyphDef' can contain either of the following:
//
// 1. In the simplest case, an 'altGlyphDef' contains one or more 'glyphRef' elements.
// Each 'glyphRef' element references a single glyph within a particular font.
// If all of the referenced glyphs are available, then these glyphs are rendered
// instead of the character(s) inside of the referencing 'altGlyph' element.
// If any of the referenced glyphs are unavailable, then the character(s) that are
// inside of the 'altGlyph' element are rendered as if there were not an 'altGlyph'
// element surrounding those characters.
//
// 2. In the more complex case, an 'altGlyphDef' contains one or more 'altGlyphItem' elements.
// Each 'altGlyphItem' represents a candidate set of substitute glyphs. Each 'altGlyphItem'
// contains one or more 'glyphRef' elements. Each 'glyphRef' element references a single
// glyph within a particular font. The first 'altGlyphItem' in which all referenced glyphs
// are available is chosen. The glyphs referenced from this 'altGlyphItem' are rendered
// instead of the character(s) that are inside of the referencing 'altGlyph' element.
// If none of the 'altGlyphItem' elements result in a successful match (i.e., none of the
// 'altGlyphItem' elements has all of its referenced glyphs available), then the character(s)
// that are inside of the 'altGlyph' element are rendered as if there were not an 'altGlyph'
// element surrounding those characters.
//
// The spec doesn't tell how to deal with the mixing of <glyphRef> and <altGlyItem>.
// However, we determine content model by the type of the first appearing element
// just like Opera 11 does. After the content model is determined we skip elements
// which don't comform to it. For example:
// a. <altGlyphDef>
// <glyphRef id="g1" />
// <altGlyphItem id="i1"> ... </altGlyphItem>
// <glyphRef id="g2" />
// </altGlyphDef>
//
// b. <altGlyphDef>
// <altGlyphItem id="i1"> ... </altGlyphItem>
// <altGlyphItem id="i2"> ... </altGlyphItem>
// <glyphRef id="g1" />
// <glyphRef id="g2" />
// </altGlyphDef>
// For a), the content model is 1), so we will use "g1" and "g2" if they are all valid
// and "i1" is skipped.
// For b), the content model is 2), so we will use <glyphRef> elements contained in
// "i1" if they are valid and "g1" and "g2" are skipped.
// These 2 variables are used to determine content model.
bool fountFirstGlyphRef = false;
bool foundFirstAltGlyphItem = false;
for (auto& child : childrenOfType<SVGElement>(*this)) {
if (!foundFirstAltGlyphItem && is<SVGGlyphRefElement>(child)) {
fountFirstGlyphRef = true;
String referredGlyphName;
if (downcast<SVGGlyphRefElement>(child).hasValidGlyphElement(referredGlyphName))
glyphNames.append(referredGlyphName);
else {
// As the spec says "If any of the referenced glyphs are unavailable,
// then the character(s) that are inside of the 'altGlyph' element are
// rendered as if there were not an 'altGlyph' element surrounding
// those characters.".
glyphNames.clear();
return false;
}
} else if (!fountFirstGlyphRef && is<SVGAltGlyphItemElement>(child)) {
foundFirstAltGlyphItem = true;
// As the spec says "The first 'altGlyphItem' in which all referenced glyphs
// are available is chosen."
if (downcast<SVGAltGlyphItemElement>(child).hasValidGlyphElements(glyphNames) && !glyphNames.isEmpty())
return true;
}
}
return !glyphNames.isEmpty();
}
}