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Diffstat (limited to 'dviware/dvisvgm/src/optimizer/ClipPathReassigner.cpp')
-rw-r--r--dviware/dvisvgm/src/optimizer/ClipPathReassigner.cpp94
1 files changed, 94 insertions, 0 deletions
diff --git a/dviware/dvisvgm/src/optimizer/ClipPathReassigner.cpp b/dviware/dvisvgm/src/optimizer/ClipPathReassigner.cpp
new file mode 100644
index 0000000000..0f684cd7eb
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+++ b/dviware/dvisvgm/src/optimizer/ClipPathReassigner.cpp
@@ -0,0 +1,94 @@
+/*************************************************************************
+** ClipPathReassigner.cpp **
+** **
+** This file is part of dvisvgm -- a fast DVI to SVG converter **
+** Copyright (C) 2005-2022 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 <algorithm>
+#include <set>
+#include <sstream>
+#include "ClipPathReassigner.hpp"
+#include "../XMLNode.hpp"
+#include "../XXHashFunction.hpp"
+
+using namespace std;
+
+const char* ClipPathReassigner::info () const {
+ return "remove duplicate clip paths and update the references";
+}
+
+
+/** Returns a hash value for an XML element where the id attribute is not taken into account.
+ * Two elements that differ only by their id attribute get the same hash value. */
+static uint64_t hash_value (XMLElement *elem) {
+ const char *id = elem->getAttributeValue("id");
+ elem->removeAttribute("id");
+ ostringstream oss;
+ elem->write(oss);
+ uint64_t value = XXH64HashFunction(oss.str().data(), oss.str().length()).digestValue();
+ if (id)
+ elem->addAttribute("id", id);
+ return value;
+}
+
+
+/** Extracts the ID from a local URL reference like url(#abcde) */
+static inline string extract_id_from_url (const string &url) {
+ if (url.length() >= 7) {
+ size_t first = url.find('#');
+ size_t last = url.rfind(')');
+ if (first != string::npos && last != string::npos && first < last)
+ return url.substr(first+1, last-first-1);
+ }
+ return "";
+}
+
+
+void ClipPathReassigner::execute (XMLElement *defs, XMLElement *context) {
+ vector<XMLElement*> clipPathElements;
+ if (!defs || !context || !defs->getDescendants("clipPath", nullptr, clipPathElements))
+ return;
+ map<uint64_t, vector<XMLElement*>> clipPathMap;
+ for (XMLElement *clipPathElement: clipPathElements) {
+ uint64_t hash = hash_value(clipPathElement);
+ clipPathMap[hash].push_back(clipPathElement); // put identical clipPath elements into a common vector
+ }
+ // replace clip path references
+ vector<XMLElement*> descendants;
+ context->getDescendants(nullptr, "clip-path", descendants);
+ for (auto &mapEntry : clipPathMap) {
+ vector<XMLElement*> &identicalClipPathElements = mapEntry.second;
+ set<string> ids;
+ for (auto elem : identicalClipPathElements)
+ ids.insert(elem->getAttributeValue("id"));
+ for (auto it = descendants.begin(); it != descendants.end();) {
+ string id = extract_id_from_url((*it)->getAttributeValue("clip-path"));
+ if (ids.find(id) == ids.end())
+ ++it;
+ else {
+ (*it)->addAttribute("clip-path", string("url(#") + (*ids.begin()) + ")");
+ it = descendants.erase(it); // no need to process this element again
+ }
+ }
+ }
+ // remove redundant clipPath elements
+ for (auto mapEntry : clipPathMap) {
+ auto it = mapEntry.second.begin();
+ for (++it; it != mapEntry.second.end(); ++it)
+ XMLElement::detach(*it);
+ }
+}