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/*************************************************************************
** PSPreviewHandler.cpp **
** **
** This file is part of dvisvgm -- a fast DVI to SVG converter **
** Copyright (C) 2005-2024 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 "PSInterpreter.hpp"
#include "PSPreviewHandler.hpp"
using namespace std;
PSPreviewHandler::PSPreviewHandler (PSInterpreter &psi) : _psi(psi) {
}
/** Activates this filter so that the PS code will be redirected through it if
* it's hooked into the PSInterpreter. */
void PSPreviewHandler::init () {
// try to retrieve version string of preview package set in the PS header section
if (_psi.executeRaw("SDict begin currentdict/preview@version known{preview@version}{0}ifelse end", 1))
_version = _psi.rawData()[0];
// check if tightpage option was set
if (_version != "0" && _psi.executeRaw("SDict begin preview@tightpage end", 1))
_tightpage = (_psi.rawData()[0] == "true");
_boxExtents.clear();
}
/** Tries to extract the bounding box information from the PS operand stack.
@return true on success. */
bool PSPreviewHandler::readDataFromStack () {
if (!_tightpage)
return false;
// Read bounding box information pushed on the operand stack by the preview package.
// It consists of 7 values in DVI units:
// adj_left, adj_bottom, adj_right, adj_top, height, depth, width,
// where the first 4 values are set by \PreviewBorder or \PreviewBbAdjust. They denote
// the border adjustments to create additional space around the graphics.
// The baseline of the tight box extends from (0,0) to (tight_width, 0).
const char *getOperands =
"count 7 sub neg dup 0 lt{pop 0}if{0}repeat\n" // ensure 7 operands on the stack
"7{dup type dup /integertype eq exch /realtype eq or not{pop 0}if cvi 7 1 roll} repeat"; // ensure integer operands
_psi.executeRaw(getOperands, 7);
_boxExtents.clear();
for (const string &str: _psi.rawData())
_boxExtents.push_back(stoi(str));
return true;
}
/** Returns the bounding box defined by the preview package. */
bool PSPreviewHandler::getBoundingBox (BoundingBox &bbox) const {
if (_boxExtents.size() < 7)
return false;
const double leftX = _boxExtents[0]*_dvi2bp;
bbox = BoundingBox(leftX, -height(), width()+leftX, depth());
return true;
}
/** Returns the box height in PS points, or -1 if no data was found or read yet. */
double PSPreviewHandler::height () const {
return _boxExtents.size() > 4 ? (_boxExtents[4]+_boxExtents[3])*_dvi2bp : -1;
}
/** Returns the box depth in PS points, or -1 if no data was found or read yet. */
double PSPreviewHandler::depth () const {
return _boxExtents.size() > 5 ? (_boxExtents[5]-_boxExtents[1])*_dvi2bp : -1;
}
/** Returns the box width in PS points, or -1 if no data was found or read yet. */
double PSPreviewHandler::width () const {
return _boxExtents.size() > 6 ? (_boxExtents[6]+_boxExtents[2]-_boxExtents[0])*_dvi2bp : -1;
}
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