1 #define INKSCAPE_LPE_PATHALONGPATH_CPP
3 /*
4 * Copyright (C) Johan Engelen 2007 <j.b.c.engelen@utwente.nl>
5 * Copyright (C) Steren Giannini 2008 <steren.giannini@gmail.com>
6 *
7 * Released under GNU GPL, read the file 'COPYING' for more information
8 */
10 #include "live_effects/lpe-pathalongpath.h"
11 #include "sp-shape.h"
12 #include "sp-item.h"
13 #include "sp-path.h"
14 #include "sp-item-group.h"
15 #include "display/curve.h"
16 #include <libnr/n-art-bpath.h>
17 #include <libnr/nr-matrix-fns.h>
18 #include "live_effects/n-art-bpath-2geom.h"
19 #include "svg/svg.h"
20 #include "ui/widget/scalar.h"
22 #include <2geom/sbasis.h>
23 #include <2geom/sbasis-geometric.h>
24 #include <2geom/bezier-to-sbasis.h>
25 #include <2geom/sbasis-to-bezier.h>
26 #include <2geom/d2.h>
27 #include <2geom/piecewise.h>
29 #include <algorithm>
30 using std::vector;
33 /* Theory in e-mail from J.F. Barraud
34 Let B be the skeleton path, and P the pattern (the path to be deformed).
36 P is a map t --> P(t) = ( x(t), y(t) ).
37 B is a map t --> B(t) = ( a(t), b(t) ).
39 The first step is to re-parametrize B by its arc length: this is the parametrization in which a point p on B is located by its distance s from start. One obtains a new map s --> U(s) = (a'(s),b'(s)), that still describes the same path B, but where the distance along B from start to
40 U(s) is s itself.
42 We also need a unit normal to the path. This can be obtained by computing a unit tangent vector, and rotate it by 90°. Call this normal vector N(s).
44 The basic deformation associated to B is then given by:
46 (x,y) --> U(x)+y*N(x)
48 (i.e. we go for distance x along the path, and then for distance y along the normal)
50 Of course this formula needs some minor adaptations (as is it depends on the absolute position of P for instance, so a little translation is needed
51 first) but I think we can first forget about them.
52 */
54 namespace Inkscape {
55 namespace LivePathEffect {
57 LPEPathAlongPath::LPEPathAlongPath(LivePathEffectObject *lpeobject) :
58 Effect(lpeobject),
59 bend_path(_("Bend path"), _("Path along which to bend the original path"), "bendpath", &wr, this, "M0,0 L1,0"),
60 prop_scale(_("Width"), _("Width of the path"), "prop_scale", &wr, this, 1),
61 scale_y_rel(_("Width in units of length"), _("Scale the width of the path in units of its length"), "scale_y_rel", &wr, this, false),
62 vertical_pattern(_("Original path is vertical"), _("Rotates the original 90 degrees, before bending it along the bend path"), "vertical", &wr, this, false)
63 {
64 registerParameter( dynamic_cast<Parameter *>(&bend_path) );
65 registerParameter( dynamic_cast<Parameter *>(&prop_scale) );
66 registerParameter( dynamic_cast<Parameter *>(&scale_y_rel) );
67 registerParameter( dynamic_cast<Parameter *>(&vertical_pattern) );
69 prop_scale.param_set_digits(3);
70 prop_scale.param_set_increments(0.01, 0.10);
72 groupSpecialBehavior = false;
73 }
75 LPEPathAlongPath::~LPEPathAlongPath()
76 {
78 }
80 void
81 LPEPathAlongPath::doBeforeEffect (SPLPEItem *lpeitem)
82 {
83 if(SP_IS_GROUP(lpeitem))
84 {
85 groupSpecialBehavior = true;
87 using namespace Geom;
88 Piecewise<D2<SBasis> > pwd2;
89 std::vector<Geom::Path> temppath;
91 recursive_original_bbox(SP_GROUP(lpeitem), pwd2, temppath);
93 for (unsigned int i=0; i < temppath.size(); i++) {
94 pwd2.concat( temppath[i].toPwSb() );
95 }
97 D2<Piecewise<SBasis> > d2pw = make_cuts_independant(pwd2);
98 boundingbox_X = bounds_exact(d2pw[0]);
99 boundingbox_Y = bounds_exact(d2pw[1]);
100 }
102 }
105 Geom::Piecewise<Geom::D2<Geom::SBasis> >
106 LPEPathAlongPath::doEffect_pwd2 (Geom::Piecewise<Geom::D2<Geom::SBasis> > & pwd2_in)
107 {
108 using namespace Geom;
110 /* Much credit should go to jfb and mgsloan of lib2geom development for the code below! */
112 Piecewise<D2<SBasis> > uskeleton = arc_length_parametrization(Piecewise<D2<SBasis> >(bend_path.get_pwd2()),2,.1);
113 uskeleton = remove_short_cuts(uskeleton,.01);
114 Piecewise<D2<SBasis> > n = rot90(derivative(uskeleton));
115 n = force_continuity(remove_short_cuts(n,.1));
117 D2<Piecewise<SBasis> > patternd2 = make_cuts_independant(pwd2_in);
118 Piecewise<SBasis> x = vertical_pattern.get_value() ? Piecewise<SBasis>(patternd2[1]) : Piecewise<SBasis>(patternd2[0]);
119 Piecewise<SBasis> y = vertical_pattern.get_value() ? Piecewise<SBasis>(patternd2[0]) : Piecewise<SBasis>(patternd2[1]);
121 //We use the group bounding box size or the path bbox size to translate well x and y
122 if(groupSpecialBehavior == false)
123 {
124 boundingbox_X = bounds_exact(x);
125 boundingbox_Y = bounds_exact(y);
126 }
127 x-= boundingbox_X.min();
128 y-= boundingbox_Y.middle();
130 double scaling = uskeleton.cuts.back()/boundingbox_X.extent();
132 if (scaling != 1.0) {
133 x*=scaling;
134 }
136 if ( scale_y_rel.get_value() ) {
137 y*=(scaling*prop_scale);
138 } else {
139 if (prop_scale != 1.0) y *= prop_scale;
140 }
143 Piecewise<D2<SBasis> > output = compose(uskeleton,x) + y*compose(n,x);
144 return output;
145 }
147 void
148 LPEPathAlongPath::resetDefaults(SPItem * item)
149 {
150 if (SP_IS_PATH(item) || SP_IS_GROUP(item))
151 {
152 // set the bend path to run horizontally in the middle of the bounding box of the original path
153 using namespace Geom;
154 Piecewise<D2<SBasis> > pwd2;
155 std::vector<Geom::Path> temppath;
157 if (SP_IS_PATH(item))
158 {
159 //TODO : this won't work well with LPE stacking
160 temppath = SVGD_to_2GeomPath( SP_OBJECT_REPR(item)->attribute("inkscape:original-d"));
161 }
162 else if (SP_IS_GROUP(item))
163 {
164 recursive_original_bbox(SP_GROUP(item), pwd2, temppath);
165 }
167 for (unsigned int i=0; i < temppath.size(); i++) {
168 pwd2.concat( temppath[i].toPwSb() );
169 }
171 D2<Piecewise<SBasis> > d2pw = make_cuts_independant(pwd2);
172 boundingbox_X = bounds_exact(d2pw[0]);
173 boundingbox_Y = bounds_exact(d2pw[1]);
176 Point start(boundingbox_X.min(), (boundingbox_Y.max()+boundingbox_Y.min())/2);
177 Point end(boundingbox_X.max(), (boundingbox_Y.max()+boundingbox_Y.min())/2);
179 if ( Geom::are_near(start,end) ) {
180 end += Point(1.,0.);
181 }
182 Geom::Path path;
183 path.start( start );
184 path.appendNew<Geom::LineSegment>( end );
185 bend_path.param_set_and_write_new_value( path.toPwSb() );
188 }
189 }
191 void
192 LPEPathAlongPath::transform_multiply(Geom::Matrix const& postmul, bool set)
193 {
194 // TODO: implement correct transformation instead of this default behavior
195 Effect::transform_multiply(postmul, set);
196 }
199 } // namespace LivePathEffect
200 } /* namespace Inkscape */
202 /*
203 Local Variables:
204 mode:c++
205 c-file-style:"stroustrup"
206 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
207 indent-tabs-mode:nil
208 fill-column:99
209 End:
210 */
211 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :