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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* SVG data parser
*
* Authors:
* Lauris Kaplinski <lauris@kaplinski.com>
* Raph Levien <raph@acm.org>
*
* Copyright (C) 1999-2002 Lauris Kaplinski
* Copyright (C) 1999 Raph Levien
*
* Released under GNU GPL v2+, read the file 'COPYING' for more information.
*/
#include <cstring>
#include <string>
#include <cstdlib>
#include <cstdio>
#include <glib.h>
#include <2geom/transforms.h>
#include "svg.h"
#include "preferences.h"
std::string
sp_svg_transform_write(Geom::Affine const &transform)
{
Inkscape::Preferences *prefs = Inkscape::Preferences::get();
// this must be a bit grater than EPSILON
double e = 1e-5 * transform.descrim();
int prec = prefs->getInt("/options/svgoutput/numericprecision", 8);
int min_exp = prefs->getInt("/options/svgoutput/minimumexponent", -8);
// Special case: when all fields of the affine are zero,
// the optimized transformation is scale(0)
if (transform[0] == 0 && transform[1] == 0 && transform[2] == 0 &&
transform[3] == 0 && transform[4] == 0 && transform[5] == 0)
{
return "scale(0)";
}
std::stringstream c(""); // string buffer
if (transform.isIdentity()) {
// We are more or less identity, so no transform attribute needed:
return {};
} else if (transform.isScale()) {
// We are more or less a uniform scale
c << "scale(";
c << sp_svg_number_write_de(transform[0], prec, min_exp);
if (Geom::are_near(transform[0], transform[3], e)) {
c << ")";
} else {
c << ",";
c << sp_svg_number_write_de(transform[3], prec, min_exp);
c << ")";
}
} else if (transform.isTranslation()) {
// We are more or less a pure translation
c << "translate(";
c << sp_svg_number_write_de(transform[4], prec, min_exp);
if (Geom::are_near(transform[5], 0.0, e)) {
c << ")";
} else {
c << ",";
c << sp_svg_number_write_de(transform[5], prec, min_exp);
c << ")";
}
} else if (transform.isRotation()) {
// We are more or less a pure rotation
c << "rotate(";
double angle = std::atan2(transform[1], transform[0]) * (180 / M_PI);
c << sp_svg_number_write_de(angle, prec, min_exp);
c << ")";
} else if (transform.withoutTranslation().isRotation()) {
// Solution found by Johan Engelen
// Refer to the matrix in svg-affine-test.h
// We are a rotation about a special axis
c << "rotate(";
double angle = std::atan2(transform[1], transform[0]) * (180 / M_PI);
c << sp_svg_number_write_de(angle, prec, min_exp);
c << ",";
Geom::Affine const& m = transform;
double tx = (m[2]*m[5]+m[4]-m[4]*m[3]) / (1-m[3]-m[0]+m[0]*m[3]-m[2]*m[1]);
c << sp_svg_number_write_de(tx, prec, min_exp);
c << ",";
double ty = (m[1]*tx + m[5]) / (1 - m[3]);
c << sp_svg_number_write_de(ty, prec, min_exp);
c << ")";
} else if (transform.isHShear()) {
// We are more or less a pure skewX
c << "skewX(";
double angle = atan(transform[2]) * (180 / M_PI);
c << sp_svg_number_write_de(angle, prec, min_exp);
c << ")";
} else if (transform.isVShear()) {
// We are more or less a pure skewY
c << "skewY(";
double angle = atan(transform[1]) * (180 / M_PI);
c << sp_svg_number_write_de(angle, prec, min_exp);
c << ")";
} else {
c << "matrix(";
c << sp_svg_number_write_de(transform[0], prec, min_exp);
c << ",";
c << sp_svg_number_write_de(transform[1], prec, min_exp);
c << ",";
c << sp_svg_number_write_de(transform[2], prec, min_exp);
c << ",";
c << sp_svg_number_write_de(transform[3], prec, min_exp);
c << ",";
c << sp_svg_number_write_de(transform[4], prec, min_exp);
c << ",";
c << sp_svg_number_write_de(transform[5], prec, min_exp);
c << ")";
}
assert(c.str().length() <= 256);
return c.str();
}
/*
Local Variables:
mode:c++
c-file-style:"stroustrup"
c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
indent-tabs-mode:nil
fill-column:99
End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :
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