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Diffstat (limited to 'dviware/dvisvgm/src/optimizer/TextSimplifier.cpp')
-rw-r--r-- | dviware/dvisvgm/src/optimizer/TextSimplifier.cpp | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/dviware/dvisvgm/src/optimizer/TextSimplifier.cpp b/dviware/dvisvgm/src/optimizer/TextSimplifier.cpp new file mode 100644 index 0000000000..23e0e386df --- /dev/null +++ b/dviware/dvisvgm/src/optimizer/TextSimplifier.cpp @@ -0,0 +1,118 @@ +/************************************************************************* +** 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; + } + } +} |