bool SVGAltGlyphItemElement::hasValidGlyphElements(Vector<String>& glyphNames) const
{
// Spec: http://www.w3.org/TR/SVG/text.html#AltGlyphItemElement
// The ‘altGlyphItem’ element defines a candidate set of possible glyph substitutions.
// The first ‘altGlyphItem’ element whose referenced glyphs are all available is chosen.
// Its glyphs are rendered instead of the character(s) that are inside of the referencing
// ‘altGlyph’ element.
//
// Here we fill glyphNames and return true only if all referenced glyphs are valid and
// there is at least one glyph.
for (Node* child = firstChild(); child; child = child->nextSibling()) {
if (child->hasTagName(SVGNames::glyphRefTag)) {
String referredGlyphName;
if (toSVGGlyphRefElement(child)->hasValidGlyphElement(referredGlyphName))
glyphNames.append(referredGlyphName);
else {
glyphNames.clear();
return false;
}
}
}
return !glyphNames.isEmpty();
}
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 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 (Node* child = firstChild(); child; child = child->nextSibling()) {
if (!foundFirstAltGlyphItem && child->hasTagName(SVGNames::glyphRefTag)) {
fountFirstGlyphRef = true;
String referredGlyphName;
if (toSVGGlyphRefElement(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 && child->hasTagName(SVGNames::altGlyphItemTag)) {
foundFirstAltGlyphItem = true;
Vector<String> referredGlyphNames;
// As the spec says "The first 'altGlyphItem' in which all referenced glyphs
// are available is chosen."
if (static_cast<SVGAltGlyphItemElement*>(child)->hasValidGlyphElements(glyphNames) && !glyphNames.isEmpty())
return true;
}
}
return !glyphNames.isEmpty();
}
