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// SPDX-License-Identifier: GPL-2.0-or-later
/**
* @file
* LPE effect for extruding paths (making them "3D").
*
*/
/* Authors:
* Johan Engelen <j.b.c.engelen@utwente.nl>
*
* Copyright (C) 2009 Authors
*
* Released under GNU GPL v2+, read the file 'COPYING' for more information.
*/
#include "live_effects/lpe-extrude.h"
// TODO due to internal breakage in glibmm headers, this must be last:
#include <glibmm/i18n.h>
namespace Inkscape {
namespace LivePathEffect {
LPEExtrude::LPEExtrude(LivePathEffectObject *lpeobject) :
Effect(lpeobject),
extrude_vector(_("Direction"), _("Defines the direction and magnitude of the extrusion"), "extrude_vector", &wr, this, Geom::Point(-10,10))
{
show_orig_path = true;
concatenate_before_pwd2 = false;
registerParameter(&extrude_vector);
}
LPEExtrude::~LPEExtrude()
= default;
static bool are_colinear(Geom::Point a, Geom::Point b) {
return Geom::are_near(cross(a,b), 0., 0.5);
}
// find cusps, except at start/end for closed paths.
// this should be factored out later.
static std::vector<double> find_cusps( Geom::Piecewise<Geom::D2<Geom::SBasis> > const & pwd2_in ) {
using namespace Geom;
Piecewise<D2<SBasis> > deriv = derivative(pwd2_in);
std::vector<double> cusps;
// cusps are spots where the derivative jumps.
for (unsigned i = 1 ; i < deriv.size() ; ++i) {
if ( ! are_colinear(deriv[i-1].at1(), deriv[i].at0()) ) {
// there is a jump in the derivative, so add it to the cusps list
cusps.push_back(deriv.cuts[i]);
}
}
return cusps;
}
Geom::Piecewise<Geom::D2<Geom::SBasis> >
LPEExtrude::doEffect_pwd2 (Geom::Piecewise<Geom::D2<Geom::SBasis> > const & pwd2_in)
{
using namespace Geom;
// generate connecting lines (the 'sides' of the extrusion)
Geom::Path path(Point(0.,0.));
path.appendNew<Geom::LineSegment>( extrude_vector.getVector() );
Piecewise<D2<SBasis> > connector = path.toPwSb();
switch( 1 ) {
case 0: {
/* This one results in the following subpaths: the original, a displaced copy, and connector lines between the two
*/
Piecewise<D2<SBasis> > pwd2_out = pwd2_in;
// generate extrusion bottom: (just a copy of original path, displaced a bit)
pwd2_out.concat( pwd2_in + extrude_vector.getVector() );
// connecting lines should be put at start and end of path if it is not closed
// it is not possible to check whether a piecewise<T> path is closed,
// so we check whether start and end are close
if ( ! are_near(pwd2_in.firstValue(), pwd2_in.lastValue()) ) {
pwd2_out.concat( connector + pwd2_in.firstValue() );
pwd2_out.concat( connector + pwd2_in.lastValue() );
}
// connecting lines should be put at cusps
Piecewise<D2<SBasis> > deriv = derivative(pwd2_in);
std::vector<double> cusps; // = roots(deriv);
for (double cusp : cusps) {
pwd2_out.concat( connector + pwd2_in.valueAt(cusp) );
}
// connecting lines should be put where the tangent of the path equals the extrude_vector in direction
std::vector<double> rts = roots(dot(deriv, rot90(extrude_vector.getVector())));
for (double rt : rts) {
pwd2_out.concat( connector + pwd2_in.valueAt(rt) );
}
return pwd2_out;
}
default:
case 1: {
/* This one creates separate closed subpaths that correspond to the faces of the extruded shape.
* When the LPE is complete, one can convert the shape to a normal path, then break subpaths apart and start coloring them.
*/
Piecewise<D2<SBasis> > pwd2_out;
// split input path in pieces between points where deriv == vector
Piecewise<D2<SBasis> > deriv = derivative(pwd2_in);
std::vector<double> rts = roots(dot(deriv, rot90(extrude_vector.getVector())));
std::vector<double> cusps = find_cusps(pwd2_in);
// see if we should treat the path as being closed.
bool closed_path = false;
if ( are_near(pwd2_in.firstValue(), pwd2_in.lastValue()) ) {
// the path is closed, however if there is a cusp at the closing point, we should treat it as being an open path.
if ( are_colinear(deriv.firstValue(), deriv.lastValue()) ) {
// there is no jump in the derivative, so treat path as being closed
closed_path = true;
}
}
std::vector<double> connector_pts;
if (rts.empty()) {
connector_pts = cusps;
} else if (cusps.empty()) {
connector_pts = rts;
} else {
connector_pts = rts;
connector_pts.insert(connector_pts.begin(), cusps.begin(), cusps.end());
sort(connector_pts.begin(), connector_pts.end());
}
double portion_t = 0.;
for (unsigned i = 0; i < connector_pts.size() ; ++i) {
Piecewise<D2<SBasis> > cut = portion(pwd2_in, portion_t, connector_pts[i] );
portion_t = connector_pts[i];
if (closed_path && i == 0) {
// if the path is closed, skip the first cut and add it to the last cut later
continue;
}
Piecewise<D2<SBasis> > part = cut;
part.continuousConcat(connector + cut.lastValue());
part.continuousConcat(reverse(cut) + extrude_vector.getVector());
part.continuousConcat(reverse(connector) + cut.firstValue());
pwd2_out.concat( part );
}
if (closed_path) {
Piecewise<D2<SBasis> > cut = portion(pwd2_in, portion_t, pwd2_in.domain().max() );
cut.continuousConcat(portion(pwd2_in, pwd2_in.domain().min(), connector_pts[0] ));
Piecewise<D2<SBasis> > part = cut;
part.continuousConcat(connector + cut.lastValue());
part.continuousConcat(reverse(cut) + extrude_vector.getVector());
part.continuousConcat(reverse(connector) + cut.firstValue());
pwd2_out.concat( part );
} else if (!are_near(portion_t, pwd2_in.domain().max())) {
Piecewise<D2<SBasis> > cut = portion(pwd2_in, portion_t, pwd2_in.domain().max() );
Piecewise<D2<SBasis> > part = cut;
part.continuousConcat(connector + cut.lastValue());
part.continuousConcat(reverse(cut) + extrude_vector.getVector());
part.continuousConcat(reverse(connector) + cut.firstValue());
pwd2_out.concat( part );
}
return pwd2_out;
}
}
}
void
LPEExtrude::resetDefaults(SPItem const* item)
{
Effect::resetDefaults(item);
using namespace Geom;
Geom::OptRect bbox = item->geometricBounds();
if (bbox) {
Interval const &boundingbox_X = (*bbox)[Geom::X];
Interval const &boundingbox_Y = (*bbox)[Geom::Y];
extrude_vector.set_and_write_new_values( Geom::Point(boundingbox_X.middle(), boundingbox_Y.middle()),
(boundingbox_X.extent() + boundingbox_Y.extent())*Geom::Point(-0.05,0.2) );
}
}
} //namespace LivePathEffect
} /* namespace Inkscape */
/*
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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