1 #define INKSCAPE_LPE_TANGENT_TO_CURVE_CPP
2 /** \file
3 * Implementation of tangent-to-curve LPE.
4 */
6 /*
7 * Authors:
8 * Johan Engelen
9 * Maximilian Albert
10 *
11 * Copyright (C) Johan Engelen 2007 <j.b.c.engelen@utwente.nl>
12 * Copyright (C) Maximilian Albert 2008 <maximilian.albert@gmail.com>
13 *
14 * Released under GNU GPL, read the file 'COPYING' for more information
15 */
17 #include "live_effects/lpe-tangent_to_curve.h"
18 // FIXME: The following are only needed to convert the path's SPCurve* to pwd2.
19 // There must be a more convenient way to achieve this.
20 #include "sp-path.h"
21 #include "display/curve.h"
23 #include <2geom/path.h>
24 #include <2geom/transforms.h>
26 namespace Inkscape {
27 namespace LivePathEffect {
29 namespace TtC {
31 class KnotHolderEntityAttachPt : public LPEKnotHolderEntity
32 {
33 public:
34 virtual void knot_set(Geom::Point const &p, Geom::Point const &origin, guint state);
35 virtual Geom::Point knot_get();
36 };
38 class KnotHolderEntityLeftEnd : public LPEKnotHolderEntity
39 {
40 public:
41 virtual void knot_set(Geom::Point const &p, Geom::Point const &origin, guint state);
42 virtual Geom::Point knot_get();
43 };
45 class KnotHolderEntityRightEnd : public LPEKnotHolderEntity
46 {
47 public:
48 virtual void knot_set(Geom::Point const &p, Geom::Point const &origin, guint state);
49 virtual Geom::Point knot_get();
50 };
52 } // namespace TtC
54 LPETangentToCurve::LPETangentToCurve(LivePathEffectObject *lpeobject) :
55 Effect(lpeobject),
56 angle(_("Angle"), _("Additional angle between tangent and curve"), "angle", &wr, this, 0.0),
57 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),
58 length_left(_("Length left"), _("Specifies the left end of the tangent"), "length-left", &wr, this, 150),
59 length_right(_("Length right"), _("Specifies the right end of the tangent"), "length-right", &wr, this, 150)
60 {
61 show_orig_path = true;
63 registerParameter( dynamic_cast<Parameter *>(&angle) );
64 registerParameter( dynamic_cast<Parameter *>(&t_attach) );
65 registerParameter( dynamic_cast<Parameter *>(&length_left) );
66 registerParameter( dynamic_cast<Parameter *>(&length_right) );
68 registerKnotHolderHandle(new TtC::KnotHolderEntityAttachPt(), _("Adjust the point of attachment of the tangent"));
69 registerKnotHolderHandle(new TtC::KnotHolderEntityLeftEnd(), _("Adjust the \"left\" end of the tangent"));
70 registerKnotHolderHandle(new TtC::KnotHolderEntityRightEnd(), _("Adjust the \"right\" end of the tangent"));
71 }
73 LPETangentToCurve::~LPETangentToCurve()
74 {
75 }
77 Geom::Piecewise<Geom::D2<Geom::SBasis> >
78 LPETangentToCurve::doEffect_pwd2 (Geom::Piecewise<Geom::D2<Geom::SBasis> > const & pwd2_in)
79 {
80 using namespace Geom;
81 Piecewise<D2<SBasis> > output;
83 ptA = pwd2_in.valueAt(t_attach);
84 derivA = unit_vector(derivative(pwd2_in).valueAt(t_attach));
86 // TODO: Why are positive angles measured clockwise, not counterclockwise?
87 Geom::Rotate rot(Geom::Rotate::from_degrees(-angle));
88 derivA = derivA * rot;
90 C = ptA - derivA * length_left;
91 D = ptA + derivA * length_right;
93 output = Piecewise<D2<SBasis> >(D2<SBasis>(Linear(C[X], D[X]), Linear(C[Y], D[Y])));
95 return output;
96 }
98 namespace TtC {
100 // TODO: make this more generic
101 static LPETangentToCurve *
102 get_effect(SPItem *item)
103 {
104 Effect *effect = sp_lpe_item_get_current_lpe(SP_LPE_ITEM(item));
105 if (effect->effectType() != TANGENT_TO_CURVE) {
106 g_print ("Warning: Effect is not of type LPETangentToCurve!\n");
107 return NULL;
108 }
109 return static_cast<LPETangentToCurve *>(effect);
110 }
112 void
113 KnotHolderEntityAttachPt::knot_set(Geom::Point const &p, Geom::Point const &/*origin*/, guint /*state*/)
114 {
115 using namespace Geom;
117 LPETangentToCurve* lpe = get_effect(item);
119 Geom::Point const s = snap_knot_position(p);
121 // FIXME: There must be a better way of converting the path's SPCurve* to pwd2.
122 SPCurve *curve = sp_path_get_curve_for_edit (SP_PATH(item));
123 Geom::PathVector pathv = curve->get_pathvector();
124 Piecewise<D2<SBasis> > pwd2;
125 for (unsigned int i=0; i < pathv.size(); i++) {
126 pwd2.concat(pathv[i].toPwSb());
127 }
129 double t0 = nearest_point(s, pwd2);
130 lpe->t_attach.param_set_value(t0);
132 // FIXME: this should not directly ask for updating the item. It should write to SVG, which triggers updating.
133 sp_lpe_item_update_patheffect (SP_LPE_ITEM(item), false, true);
134 }
136 void
137 KnotHolderEntityLeftEnd::knot_set(Geom::Point const &p, Geom::Point const &/*origin*/, guint /*state*/)
138 {
139 LPETangentToCurve *lpe = get_effect(item);
141 Geom::Point const s = snap_knot_position(p);
143 double lambda = Geom::nearest_point(s, lpe->ptA, lpe->derivA);
144 lpe->length_left.param_set_value(-lambda);
146 sp_lpe_item_update_patheffect (SP_LPE_ITEM(item), false, true);
147 }
149 void
150 KnotHolderEntityRightEnd::knot_set(Geom::Point const &p, Geom::Point const &/*origin*/, guint /*state*/)
151 {
152 LPETangentToCurve *lpe = get_effect(item);
154 Geom::Point const s = snap_knot_position(p);
156 double lambda = Geom::nearest_point(s, lpe->ptA, lpe->derivA);
157 lpe->length_right.param_set_value(lambda);
159 sp_lpe_item_update_patheffect (SP_LPE_ITEM(item), false, true);
160 }
162 Geom::Point
163 KnotHolderEntityAttachPt::knot_get()
164 {
165 LPETangentToCurve* lpe = get_effect(item);
166 return lpe->ptA;
167 }
169 Geom::Point
170 KnotHolderEntityLeftEnd::knot_get()
171 {
172 LPETangentToCurve *lpe = get_effect(item);
173 return lpe->C;
174 }
176 Geom::Point
177 KnotHolderEntityRightEnd::knot_get()
178 {
179 LPETangentToCurve *lpe = get_effect(item);
180 return lpe->D;
181 }
183 } // namespace TtC
185 } //namespace LivePathEffect
186 } /* namespace Inkscape */
188 /*
189 Local Variables:
190 mode:c++
191 c-file-style:"stroustrup"
192 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
193 indent-tabs-mode:nil
194 fill-column:99
195 End:
196 */
197 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :