1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
|
/*************************************************************************
** RedundantElementRemover.cpp **
** **
** This file is part of dvisvgm -- a fast DVI to SVG converter **
** Copyright (C) 2005-2020 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 "DependencyGraph.hpp"
#include "RedundantElementRemover.hpp"
#include "../XMLNode.hpp"
using namespace std;
const char* RedundantElementRemover::info () const {
return "remove redundant 'clipPath' elements";
}
/** Extracts the ID from a local URL reference like url(#abcde) */
static inline string extract_id_from_url (const string &url) {
return url.substr(5, url.length()-6);
}
/** Removes elements present in the SVG tree that are not required.
* For now, only clipPath elements are removed. */
void RedundantElementRemover::execute (XMLElement *defs, XMLElement *context) {
vector<XMLElement*> clipPathElements;
if (!defs || !context || !defs->getDescendants("clipPath", nullptr, clipPathElements))
return;
// collect dependencies between clipPath elements in the defs section of the SVG tree
DependencyGraph<string> idTree;
for (const XMLElement *clip : clipPathElements) {
if (const char *id = clip->getAttributeValue("id")) {
if (const char *url = clip->getAttributeValue("clip-path"))
idTree.insert(extract_id_from_url(url), id);
else
idTree.insert(id);
}
}
// collect elements that reference a clipPath, i.e. have a clip-path attribute
vector<XMLElement*> descendants;
defs->getDescendants("!clipPath", "clip-path", descendants);
context->getDescendants(nullptr, "clip-path", descendants);
// remove referenced IDs and their dependencies from the dependency graph
for (const XMLElement *elem : descendants) {
string idref = extract_id_from_url(elem->getAttributeValue("clip-path"));
idTree.removeDependencyPath(idref);
}
descendants.clear();
for (const string &str : idTree.getKeys()) {
XMLElement *node = defs->getFirstDescendant("clipPath", "id", str.c_str());
XMLElement::detach(node);
}
}
|