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diff --git a/dviware/dvisvgm/src/optimizer/TextSimplifier.cpp b/dviware/dvisvgm/src/optimizer/TextSimplifier.cpp
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+/*************************************************************************
+** TextSimplifier.cpp **
+** **
+** This file is part of dvisvgm -- a fast DVI to SVG converter **
+** Copyright (C) 2005-2019 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 (AttributeExtractor::inheritable(attrib))
+ 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 XMLElement::Attribute &attr : attribs)
+ context->addAttribute(attr.name, attr.value);
+ // remove all common attributes from the tspan elements
+ for (XMLElement *tspan : tspans) {
+ for (const XMLElement::Attribute &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;
+ }
+ }
+}