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/*************************************************************************
** DvisvgmSpecialHandler.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 <array>
#include <cstring>
#include <utility>
#include "Calculator.hpp"
#include "DvisvgmSpecialHandler.hpp"
#include "GraphicsPathParser.hpp"
#include "InputBuffer.hpp"
#include "InputReader.hpp"
#include "Length.hpp"
#include "SpecialActions.hpp"
#include "SVGTree.hpp"
#include "utility.hpp"
#include "XMLNode.hpp"
#include "XMLString.hpp"
using namespace std;
void SVGParser::assign (SVGTree &svg, Append append, PushContext pushContext, PopContext popContext) {
_svg = &svg;
_append = append;
_pushContext = pushContext;
_popContext = popContext;
setRootElement(nullptr);
}
XMLElement* SVGParser::openElement (const std::string &tag) {
XMLElement *elem = XMLParser::openElement(tag);
if (elem->name() == "path" || elem->name() == "svg:path") {
if (const char *d = elem->getAttributeValue("d")) {
try {
// parse and reformat path definition
auto path = GraphicsPathParser<double>().parse(d);
ostringstream oss;
path.writeSVG(oss, SVGTree::RELATIVE_PATH_CMDS);
elem->addAttribute("d", oss.str());
}
catch (const GraphicsPathParserException &e) {
throw XMLParserException(string("error in path data: ")+e.what());
}
}
}
return elem;
}
void SVGParser::appendNode (unique_ptr<XMLNode> node) {
(_svg->*_append)(std::move(node));
}
XMLElement* SVGParser::finishPushContext (unique_ptr<XMLElement> elem) {
unique_ptr<SVGElement> svgElement{static_cast<SVGElement*>(elem.release())};
XMLElement *elemPtr = svgElement.get();
(_svg->*_pushContext)(std::move(svgElement));
return elemPtr;
}
void SVGParser::finishPopContext () {
(_svg->*_popContext)();
}
XMLElement* SVGParser::createElementPtr (std::string name) const {
return new SVGElement(std::move(name));
}
///////////////////////////////////////////////////////////////////////////
DvisvgmSpecialHandler::DvisvgmSpecialHandler () : _currentMacro(_macros.end())
{
}
void DvisvgmSpecialHandler::preprocess (const string&, istream &is, SpecialActions&) {
struct Command {
const char *name;
void (DvisvgmSpecialHandler::*handler)(InputReader&);
};
constexpr array<Command, 5> commands {{
{"raw", &DvisvgmSpecialHandler::preprocessRaw},
{"rawdef", &DvisvgmSpecialHandler::preprocessRawDef},
{"rawset", &DvisvgmSpecialHandler::preprocessRawSet},
{"endrawset", &DvisvgmSpecialHandler::preprocessEndRawSet},
{"rawput", &DvisvgmSpecialHandler::preprocessRawPut}
}};
StreamInputReader ir(is);
const string cmdstr = ir.getWord();
auto it = find_if(commands.begin(), commands.end(), [&](const Command &cmd) {
return cmd.name == cmdstr;
});
if (it != commands.end()) {
ir.skipSpace();
(this->*it->handler)(ir);
}
}
void DvisvgmSpecialHandler::preprocessRawSet (InputReader &ir) {
_nestingLevel++;
string id = ir.getString();
if (id.empty())
throw SpecialException("definition of unnamed SVG fragment");
if (_nestingLevel > 1)
throw SpecialException("nested definition of SVG fragment '" + id + "'");
_currentMacro = _macros.find(id);
if (_currentMacro != _macros.end()) {
_currentMacro = _macros.end();
throw SpecialException("redefinition of SVG fragment '" + id + "'");
}
pair<MacroMap::iterator, bool> state = _macros.emplace(id, StringVector());
_currentMacro = state.first;
}
void DvisvgmSpecialHandler::preprocessEndRawSet (InputReader&) {
if (_nestingLevel > 0 && --_nestingLevel == 0)
_currentMacro = _macros.end();
}
void DvisvgmSpecialHandler::preprocessRaw (InputReader &ir) {
if (_currentMacro == _macros.end())
return;
string str = ir.getLine();
if (!str.empty())
_currentMacro->second.emplace_back("P"+str);
}
void DvisvgmSpecialHandler::preprocessRawDef (InputReader &ir) {
if (_currentMacro == _macros.end())
return;
string str = ir.getLine();
if (!str.empty())
_currentMacro->second.emplace_back("D"+str);
}
void DvisvgmSpecialHandler::preprocessRawPut (InputReader &ir) {
if (_currentMacro != _macros.end())
throw SpecialException("dvisvgm:rawput not allowed inside rawset/endrawset");
}
/** Evaluates and executes a dvisvgm special statement.
* @param[in] prefix special prefix read by the SpecialManager
* @param[in] is the special statement is read from this stream
* @param[in] actions object providing the actions that can be performed by the SpecialHandler */
bool DvisvgmSpecialHandler::process (const string &prefix, istream &is, SpecialActions &actions) {
struct Command {
const char *name;
void (DvisvgmSpecialHandler::*handler)(InputReader&, SpecialActions&);
};
constexpr array<Command, 7> commands {{
{"raw", &DvisvgmSpecialHandler::processRaw},
{"rawdef", &DvisvgmSpecialHandler::processRawDef},
{"rawset", &DvisvgmSpecialHandler::processRawSet},
{"endrawset", &DvisvgmSpecialHandler::processEndRawSet},
{"rawput", &DvisvgmSpecialHandler::processRawPut},
{"bbox", &DvisvgmSpecialHandler::processBBox},
{"img", &DvisvgmSpecialHandler::processImg}
}};
StreamInputReader ir(is);
const string cmdstr = ir.getWord();
auto it = find_if(commands.begin(), commands.end(), [&](const Command &cmd) {
return cmd.name == cmdstr;
});
if (it != commands.end()) {
ir.skipSpace();
(this->*it->handler)(ir, actions);
}
return true;
}
/** Replaces constants of the form {?name} by their corresponding value.
* @param[in,out] str text to expand
* @param[in] actions interfcae to the world outside the special handler */
static void expand_constants (string &str, SpecialActions &actions) {
bool repl_bbox = true;
while (repl_bbox) {
const auto pos = str.find("{?bbox ");
if (pos == string::npos)
repl_bbox = false;
else {
auto endpos = pos+7;
while (endpos < str.length() && isalnum(str[endpos]))
++endpos;
if (str[endpos] != '}')
repl_bbox = false;
else {
BoundingBox &box = actions.bbox(str.substr(pos+7, endpos-pos-7));
str.replace(pos, endpos-pos+1, box.svgViewBoxString());
}
}
}
struct Constant {
const char *name;
string val;
};
const array<Constant, 5> constants {{
{"x", XMLString(actions.getX())},
{"y", XMLString(actions.getY())},
{"color", actions.getColor().svgColorString()},
{"matrix", actions.getMatrix().toSVG()},
{"nl", "\n"},
}};
for (const Constant &constant : constants) {
const string pattern = string("{?")+constant.name+"}";
auto pos = str.find(pattern);
while (pos != string::npos) {
str.replace(pos, strlen(constant.name)+3, constant.val);
pos = str.find(pattern, pos+constant.val.length()); // look for further matches
}
}
}
/** Evaluates substrings of the form {?(expr)} where 'expr' is a math expression,
* and replaces the substring by the computed value.
* @param[in,out] str string to scan for expressions */
static void evaluate_expressions (string &str, const SpecialActions &actions) {
auto left = str.find("{?("); // start position of expression macro
while (left != string::npos) {
auto right = str.find(")}", left+2); // end position of expression macro
if (right == string::npos)
break;
Calculator calc;
calc.setVariable("x", actions.getX());
calc.setVariable("y", actions.getY());
string expr = str.substr(left+3, right-left-3); // math expression to evaluate
if (util::normalize_space(expr).empty()) // no expression given, e.g. {?( )}
str.erase(left, right-left+2); // => replace with empty string
else {
try {
double val = calc.eval(expr);
XMLString valstr(val);
str.replace(left, right-left+2, valstr);
right = left+valstr.length()-1;
}
catch (CalculatorException &e) {
throw SpecialException(string(e.what())+" in '{?("+expr+")}'");
}
}
left = str.find("{?(", right+1); // find next expression macro
}
}
/** Processes raw SVG fragments from the input stream. The SVG data must represent
* a single or multiple syntactically complete XML parts, like opening/closing tags,
* comments, or CDATA blocks. These must not be split and distributed over several
* 'raw' statements. Elements can be split but element tags can't.
* Example: "<g transform=" is invalid, "<g transform='scale(2,3)'>" is ok. */
void DvisvgmSpecialHandler::processRaw (InputReader &ir, SpecialActions &actions) {
if (_nestingLevel == 0) {
string xml = ir.getLine();
if (!xml.empty()) {
evaluate_expressions(xml, actions);
expand_constants(xml, actions);
_pageParser.parse(std::move(xml));
}
}
}
void DvisvgmSpecialHandler::processRawDef (InputReader &ir, SpecialActions &actions) {
if (_nestingLevel == 0) {
string xml = ir.getLine();
if (!xml.empty()) {
evaluate_expressions(xml, actions);
expand_constants(xml, actions);
_defsParser.parse(std::move(xml));
}
}
}
void DvisvgmSpecialHandler::processRawSet (InputReader&, SpecialActions&) {
_nestingLevel++;
}
void DvisvgmSpecialHandler::processEndRawSet (InputReader&, SpecialActions&) {
if (_nestingLevel > 0)
_nestingLevel--;
}
void DvisvgmSpecialHandler::processRawPut (InputReader &ir, SpecialActions &actions) {
if (_nestingLevel > 0)
return;
string id = ir.getString();
auto it = _macros.find(id);
if (it == _macros.end())
throw SpecialException("undefined SVG fragment '" + id + "' referenced");
StringVector &defvector = it->second;
for (string &defstr : defvector) {
char &type = defstr[0];
string def = defstr.substr(1);
if ((type == 'P' || type == 'D') && !def.empty()) {
expand_constants(def, actions);
if (type == 'P')
_pageParser.parse(std::move(def));
else { // type == 'D'
_defsParser.parse(std::move(def));
type = 'L'; // locked
}
}
}
}
/** Embeds the virtual rectangle (x, y ,w , h) into the current bounding box,
* where (x,y) is the lower left vertex composed of the current DVI position.
* @param[in] w width of the rectangle in PS point units
* @param[in] h height of the rectangle in PS point units
* @param[in] d depth of the rectangle in PS point units
* @param[in] transform if true, apply the current transformation matrix to the rectangle
* @param[in] actions object providing the actions that can be performed by the SpecialHandler */
static void update_bbox (Length w, Length h, Length d, bool transform, SpecialActions &actions) {
double x = actions.getX();
double y = actions.getY();
BoundingBox bbox1(x, y, x+w.bp(), y-h.bp());
BoundingBox bbox2(x, y, x+w.bp(), y+d.bp());
if (transform) {
bbox1.transform(actions.getMatrix());
bbox2.transform(actions.getMatrix());
}
actions.embed(bbox1);
actions.embed(bbox2);
}
/** Reads a length value including a trailing unit specifier and returns it. */
static Length read_length (InputReader &ir) {
Length length;
ir.skipSpace();
if (!isalpha(ir.peek())) {
double val = ir.getDouble();
string unit = isalpha(ir.peek()) ? ir.getString(2) : "pt";
length = Length(val, unit);
}
return length;
}
/** Evaluates the special dvisvgm:bbox.
* variant 1: dvisvgm:bbox [r[el]] <width> <height> [<depth>] [transform]
* variant 2: dvisvgm:bbox a[bs] <x1> <y1> <x2> <y2> [transform]
* variant 3: dvisvgm:bbox f[ix] <x1> <y1> <x2> <y2> [transform]
* variant 4: dvisvgm:bbox n[ew] <name>
* variant 5: dvisvgm:bbox lock | unlock */
void DvisvgmSpecialHandler::processBBox (InputReader &ir, SpecialActions &actions) {
ir.skipSpace();
if (ir.check("lock"))
actions.bbox().lock();
else if (ir.check("unlock"))
actions.bbox().unlock();
else {
int c = ir.peek();
try {
if (!isalpha(c))
c = 'r'; // no mode specifier => relative box parameters
else {
while (!isspace(ir.peek())) // skip trailing characters
ir.get();
if (c == 'n') { // "new": create new local bounding box
ir.skipSpace();
string name;
while (isalnum(ir.peek()))
name += char(ir.get());
ir.skipSpace();
if (!name.empty() && ir.eof())
actions.bbox(name, true); // create new user box
}
else if (c == 'a' || c == 'f') { // "abs" or "fix"
Length lengths[4];
for (Length &len : lengths)
len = read_length(ir);
BoundingBox b(lengths[0], lengths[1], lengths[2], lengths[3]);
ir.skipSpace();
if (ir.check("transform"))
b.transform(actions.getMatrix());
if (c == 'a')
actions.embed(b);
else {
actions.bbox() = b;
actions.bbox().lock();
}
}
}
if (c == 'r') {
Length w = read_length(ir);
Length h = read_length(ir);
Length d = read_length(ir);
ir.skipSpace();
update_bbox(w, h, d, ir.check("transform"), actions);
}
}
catch (const UnitException &e) {
throw SpecialException(string("dvisvgm:bbox: ") + e.what());
}
}
}
void DvisvgmSpecialHandler::processImg (InputReader &ir, SpecialActions &actions) {
try {
Length w = read_length(ir);
Length h = read_length(ir);
string f = ir.getString();
update_bbox(w, h, Length(0), false, actions);
auto img = util::make_unique<SVGElement>("image");
img->addAttribute("x", actions.getX());
img->addAttribute("y", actions.getY());
img->addAttribute("width", w.bp());
img->addAttribute("height", h.bp());
img->addAttribute("xlink:href", f);
img->setTransform(actions.getMatrix());
actions.svgTree().appendToPage(std::move(img));
}
catch (const UnitException &e) {
throw SpecialException(string("dvisvgm:img: ") + e.what());
}
}
void DvisvgmSpecialHandler::dviPreprocessingFinished () {
string id;
if (_currentMacro != _macros.end())
id = _currentMacro->first;
// ensure all pattern definitions are closed after pre-processing the whole DVI file
_currentMacro = _macros.end();
_nestingLevel = 0;
if (!id.empty())
throw SpecialException("missing dvisvgm:endrawset for SVG fragment '" + id + "'");
}
void DvisvgmSpecialHandler::dviBeginPage (unsigned, SpecialActions &actions) {
SVGTree &svg = actions.svgTree();
_defsParser.assign(svg, &SVGTree::appendToDefs, &SVGTree::pushDefsContext, &SVGTree::popDefsContext);
_pageParser.assign(svg, &SVGTree::appendToPage, &SVGTree::pushPageContext, &SVGTree::popPageContext);
}
void DvisvgmSpecialHandler::dviEndPage (unsigned, SpecialActions &actions) {
_defsParser.finish();
_pageParser.finish();
actions.bbox().unlock();
for (auto &strvecpair : _macros) {
StringVector &vec = strvecpair.second;
for (string &str : vec) {
// activate locked parts of a pattern again
if (str[0] == 'L')
str[0] = 'D';
}
}
}
vector<const char*> DvisvgmSpecialHandler::prefixes() const {
vector<const char*> pfx {"dvisvgm:"};
return pfx;
}
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