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-rw-r--r--src/live_effects/lpe-tangent_to_curve.cpp206
1 files changed, 206 insertions, 0 deletions
diff --git a/src/live_effects/lpe-tangent_to_curve.cpp b/src/live_effects/lpe-tangent_to_curve.cpp
new file mode 100644
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+++ b/src/live_effects/lpe-tangent_to_curve.cpp
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+// SPDX-License-Identifier: GPL-2.0-or-later
+/** \file
+ * Implementation of tangent-to-curve LPE.
+ */
+
+/*
+ * Authors:
+ * Johan Engelen
+ * 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 v2+, read the file 'COPYING' for more information.
+ */
+
+#include "lpe-tangent_to_curve.h"
+
+#include "display/curve.h"
+
+#include "object/sp-shape.h"
+#include "object/sp-object-group.h"
+#include "ui/knot/knot-holder.h"
+#include "ui/knot/knot-holder-entity.h"
+
+// TODO due to internal breakage in glibmm headers, this must be last:
+#include <glibmm/i18n.h>
+
+namespace Inkscape {
+namespace LivePathEffect {
+
+namespace TtC {
+
+class KnotHolderEntityAttachPt : public LPEKnotHolderEntity {
+public:
+ KnotHolderEntityAttachPt(LPETangentToCurve *effect) : LPEKnotHolderEntity(effect) {};
+ void knot_set(Geom::Point const &p, Geom::Point const &origin, guint state) override;
+ Geom::Point knot_get() const override;
+};
+
+class KnotHolderEntityLeftEnd : public LPEKnotHolderEntity {
+public:
+ KnotHolderEntityLeftEnd(LPETangentToCurve *effect) : LPEKnotHolderEntity(effect) {};
+ void knot_set(Geom::Point const &p, Geom::Point const &origin, guint state) override;
+ Geom::Point knot_get() const override;
+};
+
+class KnotHolderEntityRightEnd : public LPEKnotHolderEntity
+{
+public:
+ KnotHolderEntityRightEnd(LPETangentToCurve *effect) : LPEKnotHolderEntity(effect) {};
+ void knot_set(Geom::Point const &p, Geom::Point const &origin, guint state) override;
+ Geom::Point knot_get() const override;
+};
+
+} // namespace TtC
+
+LPETangentToCurve::LPETangentToCurve(LivePathEffectObject *lpeobject) :
+ Effect(lpeobject),
+ angle(_("Angle:"), _("Additional angle between tangent and curve"), "angle", &wr, this, 0.0),
+ t_attach(_("Location along curve:"), _("Location of the point of attachment along the curve (between 0.0 and number-of-segments)"), "t_attach", &wr, this, 0.5),
+ length_left(_("Length left:"), _("Specifies the left end of the tangent"), "length-left", &wr, this, 150),
+ length_right(_("Length right:"), _("Specifies the right end of the tangent"), "length-right", &wr, this, 150)
+{
+ show_orig_path = true;
+ _provides_knotholder_entities = true;
+
+ registerParameter(&angle);
+ registerParameter(&t_attach);
+ registerParameter(&length_left);
+ registerParameter(&length_right);
+}
+
+LPETangentToCurve::~LPETangentToCurve()
+= default;
+
+Geom::Piecewise<Geom::D2<Geom::SBasis> >
+LPETangentToCurve::doEffect_pwd2 (Geom::Piecewise<Geom::D2<Geom::SBasis> > const & pwd2_in)
+{
+ using namespace Geom;
+ Piecewise<D2<SBasis> > output;
+
+ ptA = pwd2_in.valueAt(t_attach);
+ derivA = unit_vector(derivative(pwd2_in).valueAt(t_attach));
+
+ // TODO: Why are positive angles measured clockwise, not counterclockwise?
+ Geom::Rotate rot(Geom::Rotate::from_degrees(-angle));
+ derivA = derivA * rot;
+
+ C = ptA - derivA * length_left;
+ D = ptA + derivA * length_right;
+
+ output = Piecewise<D2<SBasis> >(D2<SBasis>(SBasis(C[X], D[X]), SBasis(C[Y], D[Y])));
+
+ return output;
+}
+
+void
+LPETangentToCurve::addKnotHolderEntities(KnotHolder *knotholder, SPItem *item) {
+ {
+ KnotHolderEntity *e = new TtC::KnotHolderEntityAttachPt(this);
+ e->create(nullptr, item, knotholder, Inkscape::CANVAS_ITEM_CTRL_TYPE_LPE, "LPE:TangentToCurvePT",
+ _("Adjust the point of attachment of the tangent"));
+ knotholder->add(e);
+ }
+ {
+ KnotHolderEntity *e = new TtC::KnotHolderEntityLeftEnd(this);
+ e->create(nullptr, item, knotholder, Inkscape::CANVAS_ITEM_CTRL_TYPE_LPE, "LPE:TangentToCurveLeftEnd",
+ _("Adjust the <b>left</b> end of the tangent"));
+ knotholder->add(e);
+ }
+ {
+ KnotHolderEntity *e = new TtC::KnotHolderEntityRightEnd(this);
+ e->create(nullptr, item, knotholder, Inkscape::CANVAS_ITEM_CTRL_TYPE_LPE, "LPE:TangetToCurveRightEnd",
+ _("Adjust the <b>right</b> end of the tangent"));
+ knotholder->add(e);
+ }
+};
+
+namespace TtC {
+
+void
+KnotHolderEntityAttachPt::knot_set(Geom::Point const &p, Geom::Point const &/*origin*/, guint state)
+{
+ using namespace Geom;
+
+ LPETangentToCurve* lpe = dynamic_cast<LPETangentToCurve *>(_effect);
+
+ Geom::Point const s = snap_knot_position(p, state);
+
+ if ( !SP_IS_SHAPE(lpe->sp_lpe_item) ) {
+ //lpe->t_attach.param_set_value(0);
+ g_warning("LPEItem is not a path! %s:%d\n", __FILE__, __LINE__);
+ return;
+ }
+ Piecewise<D2<SBasis> > pwd2 = paths_to_pw( lpe->pathvector_before_effect );
+
+ double t0 = nearest_time(s, pwd2);
+ lpe->t_attach.param_set_value(t0);
+
+ // FIXME: this should not directly ask for updating the item. It should write to SVG, which triggers updating.
+ sp_lpe_item_update_patheffect (SP_LPE_ITEM(item), false, true);
+}
+
+void
+KnotHolderEntityLeftEnd::knot_set(Geom::Point const &p, Geom::Point const &/*origin*/, guint state)
+{
+ LPETangentToCurve *lpe = dynamic_cast<LPETangentToCurve *>(_effect);
+
+ Geom::Point const s = snap_knot_position(p, state);
+
+ double lambda = Geom::nearest_time(s, lpe->ptA, lpe->derivA);
+ lpe->length_left.param_set_value(-lambda);
+
+ sp_lpe_item_update_patheffect (SP_LPE_ITEM(item), false, true);
+}
+
+void
+KnotHolderEntityRightEnd::knot_set(Geom::Point const &p, Geom::Point const &/*origin*/, guint state)
+{
+ LPETangentToCurve *lpe = dynamic_cast<LPETangentToCurve *>(_effect);
+
+ Geom::Point const s = snap_knot_position(p, state);
+
+ double lambda = Geom::nearest_time(s, lpe->ptA, lpe->derivA);
+ lpe->length_right.param_set_value(lambda);
+
+ sp_lpe_item_update_patheffect (SP_LPE_ITEM(item), false, true);
+}
+
+Geom::Point
+KnotHolderEntityAttachPt::knot_get() const
+{
+ LPETangentToCurve const *lpe = dynamic_cast<LPETangentToCurve const*>(_effect);
+ return lpe->ptA;
+}
+
+Geom::Point
+KnotHolderEntityLeftEnd::knot_get() const
+{
+ LPETangentToCurve const *lpe = dynamic_cast<LPETangentToCurve const*>(_effect);
+ return lpe->C;
+}
+
+Geom::Point
+KnotHolderEntityRightEnd::knot_get() const
+{
+ LPETangentToCurve const *lpe = dynamic_cast<LPETangentToCurve const*>(_effect);
+ return lpe->D;
+}
+
+} // namespace TtC
+
+} //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 :