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/*************************************************************************
** TextSimplifier.cpp **
** **
** This file is part of dvisvgm -- a fast DVI to SVG converter **
** Copyright (C) 2005-2023 Martin Gieseking <martin.gieseking@uos.de> **
** **
** This program is free software; you can redistribute it and/or **
** modify it under the terms of the GNU General Public License as **
** published by the Free Software Foundation; either version 3 of **
** the License, or (at your option) any later version. **
** **
** This program 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 General Public License for more details. **
** **
** You should have received a copy of the GNU General Public License **
** along with this program; if not, see <http://www.gnu.org/licenses/>. **
*************************************************************************/
#include <vector>
#include "AttributeExtractor.hpp"
#include "TextSimplifier.hpp"
#include "../XMLNode.hpp"
using namespace std;
const char* TextSimplifier::info () const {
return "merge data of tspans into enclosing text elements";
}
/** Returns all common inheritable attributes of multiple elements. */
static XMLElement::Attributes common_inheritable_attributes (const vector<XMLElement*> &elements) {
bool intersected=false;
XMLElement::Attributes commonAttribs;
for (const XMLElement *elem : elements) {
if (commonAttribs.empty()) {
if (intersected)
break;
for (const auto &attrib : elem->attributes()) {
if (attrib.inheritable())
commonAttribs.push_back(attrib);
}
}
else {
for (auto it = commonAttribs.begin(); it != commonAttribs.end();) {
auto *attrib = elem->getAttribute(it->name);
if (!attrib || attrib->value != it->value)
it = commonAttribs.erase(it);
else
++it;
}
}
intersected = true;
}
return commonAttribs;
}
/** Returns all tspan elements of a text element if the latter doesn't contain
* any non-whitespace text nodes. Otherwise, the returned vector is empty.
* @param[in] textElement text element to check
* @return the tspan children of the text element */
static vector<XMLElement*> get_tspans (XMLElement *textElement) {
vector<XMLElement*> tspans;
bool failed=false;
for (XMLNode *child : *textElement) {
if (child->toWSNode() || child->toComment())
continue;
if (child->toText())
failed = true;
else if (XMLElement *childElement = child->toElement()) {
if (childElement->name() != "tspan")
failed = true;
else
tspans.push_back(childElement);
}
if (failed) {
tspans.clear();
break;
}
}
return tspans;
}
void TextSimplifier::execute (XMLElement *context) {
if (!context)
return;
if (context->name() == "text") {
vector<XMLElement*> tspans = get_tspans(context);
vector<XMLElement::Attribute> attribs = common_inheritable_attributes(tspans);
if (!tspans.empty() && !attribs.empty()) {
// move all common tspan attributes to the parent text element
for (const auto &attr : attribs)
context->addAttribute(attr.name, attr.value);
// remove all common attributes from the tspan elements
for (XMLElement *tspan : tspans) {
for (const auto &attr : attribs)
tspan->removeAttribute(attr.name);
// unwrap the tspan if there are no remaining attributes
if (tspan->attributes().empty())
XMLElement::unwrap(tspan);
}
}
}
else {
XMLNode *node = context->firstChild();
while (node) {
XMLNode *next = node->next(); // keep safe pointer to next node
if (XMLElement *elem = node->toElement())
execute(elem);
node = next;
}
}
}
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