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/** \file
* LPE <offset> implementation
*/
/*
* Authors:
* Maximilian Albert
*
* Copyright (C) Johan Engelen 2007 <j.b.c.engelen@utwente.nl>
* Copyright (C) Maximilian Albert 2008 <maximilian.albert@gmail.com>
*
* Released under GNU GPL, read the file 'COPYING' for more information
*/
#include <glibmm/i18n.h>
#include "live_effects/lpe-offset.h"
#include "sp-shape.h"
#include "display/curve.h"
#include <2geom/path.h>
#include <2geom/piecewise.h>
#include <2geom/sbasis-geometric.h>
#include <2geom/svg-elliptical-arc.h>
#include <2geom/transforms.h>
namespace Inkscape {
namespace LivePathEffect {
LPEOffset::LPEOffset(LivePathEffectObject *lpeobject) :
Effect(lpeobject),
offset_pt(_("Offset"), _("Handle to control the distance of the offset from the curve"), "offset_pt", &wr, this)
{
show_orig_path = true;
registerParameter(dynamic_cast<Parameter *>(&offset_pt));
}
LPEOffset::~LPEOffset()
{
}
void
LPEOffset::doOnApply(SPLPEItem const* lpeitem)
{
Geom::Point offset = *(SP_SHAPE(lpeitem)->_curve->first_point());
offset_pt.param_update_default(offset);
offset_pt.param_setValue(offset,true);
}
static void append_half_circle(Geom::Piecewise<Geom::D2<Geom::SBasis> > &pwd2,
Geom::Point const center, Geom::Point const &dir) {
using namespace Geom;
double r = L2(dir);
SVGEllipticalArc cap(center + dir, r, r, angle_between(Point(1,0), dir), false, false, center - dir);
Piecewise<D2<SBasis> > cap_pwd2(cap.toSBasis());
pwd2.continuousConcat(cap_pwd2);
}
void
LPEOffset::doBeforeEffect (SPLPEItem const* lpeitem)
{
SPLPEItem * item = const_cast<SPLPEItem*>(lpeitem);
item->apply_to_clippath(item);
item->apply_to_mask(item);
}
Geom::Piecewise<Geom::D2<Geom::SBasis> >
LPEOffset::doEffect_pwd2 (Geom::Piecewise<Geom::D2<Geom::SBasis> > const & pwd2_in)
{
using namespace Geom;
Piecewise<D2<SBasis> > output;
double t = nearest_point(offset_pt, pwd2_in);
Point A = pwd2_in.valueAt(t);
double offset = L2(A - offset_pt);
Piecewise<D2<SBasis> > der = unitVector(derivative(pwd2_in));
Piecewise<D2<SBasis> > n = rot90(der);
output = pwd2_in + n * offset;
append_half_circle(output, pwd2_in.lastValue(), n.lastValue() * offset);
output.continuousConcat(reverse(pwd2_in - n * offset));
append_half_circle(output, pwd2_in.firstValue(), -n.firstValue() * offset);
// TODO: here we should remove self-overlaps by applying the "union" boolop
// but we'd need to convert the path to a Shape, which is currently
// broken in 2geom, so we return the unaltered path
return output;
}
} //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 :
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