rename LPEPathAlongPath -> LPEBendPath

(bzr r5385)

1 files changed, 211 insertions, 0 deletions

diff --git a/src/live_effects/lpe-bendpath.cpp b/src/live_effects/lpe-bendpath.cpp
new file mode 100644
index 000000000..026c8fb5f
--- /dev/null
+++ b/src/live_effects/lpe-bendpath.cpp
@@ -0,0 +1,211 @@
+#define INKSCAPE_LPE_BENDPATH_CPP
+
+/*
+ * Copyright (C) Johan Engelen 2007 <j.b.c.engelen@utwente.nl>
+ * Copyright (C) Steren Giannini 2008 <steren.giannini@gmail.com>
+ *
+ * Released under GNU GPL, read the file 'COPYING' for more information
+ */
+
+#include "live_effects/lpe-bendpath.h"
+#include "sp-shape.h"
+#include "sp-item.h"
+#include "sp-path.h"
+#include "sp-item-group.h"
+#include "display/curve.h"
+#include <libnr/n-art-bpath.h>
+#include <libnr/nr-matrix-fns.h>
+#include "live_effects/n-art-bpath-2geom.h"
+#include "svg/svg.h"
+#include "ui/widget/scalar.h"
+
+#include <2geom/sbasis.h>
+#include <2geom/sbasis-geometric.h>
+#include <2geom/bezier-to-sbasis.h>
+#include <2geom/sbasis-to-bezier.h>
+#include <2geom/d2.h>
+#include <2geom/piecewise.h>
+
+#include <algorithm>
+using std::vector;
+
+
+/* Theory in e-mail from J.F. Barraud
+Let B be the skeleton path, and P the pattern (the path to be deformed).
+
+P is a map t --> P(t) = ( x(t), y(t) ).
+B is a map t --> B(t) = ( a(t), b(t) ).
+
+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
+U(s) is s itself.
+
+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).
+
+The basic deformation associated to B is then given by:
+
+   (x,y) --> U(x)+y*N(x)
+
+(i.e. we go for distance x along the path, and then for distance y along the normal)
+
+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
+first) but I think we can first forget about them.
+*/
+
+namespace Inkscape {
+namespace LivePathEffect {
+
+LPEBendPath::LPEBendPath(LivePathEffectObject *lpeobject) :
+    Effect(lpeobject),
+    bend_path(_("Bend path"), _("Path along which to bend the original path"), "bendpath", &wr, this, "M0,0 L1,0"),
+    prop_scale(_("Width"), _("Width of the path"), "prop_scale", &wr, this, 1),
+    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),
+    vertical_pattern(_("Original path is vertical"), _("Rotates the original 90 degrees, before bending it along the bend path"), "vertical", &wr, this, false)
+{
+    registerParameter( dynamic_cast<Parameter *>(&bend_path) );
+    registerParameter( dynamic_cast<Parameter *>(&prop_scale) );
+    registerParameter( dynamic_cast<Parameter *>(&scale_y_rel) );
+    registerParameter( dynamic_cast<Parameter *>(&vertical_pattern) );
+
+    prop_scale.param_set_digits(3);
+    prop_scale.param_set_increments(0.01, 0.10);
+
+    groupSpecialBehavior = false;
+}
+
+LPEBendPath::~LPEBendPath()
+{
+
+}
+
+void
+LPEBendPath::doBeforeEffect (SPLPEItem *lpeitem)
+{
+    if(SP_IS_GROUP(lpeitem))
+    {
+    groupSpecialBehavior = true;
+
+            using namespace Geom;
+            Piecewise<D2<SBasis> > pwd2;
+            std::vector<Geom::Path> temppath;  
+
+            recursive_original_bbox(SP_GROUP(lpeitem), pwd2, temppath);
+
+    for (unsigned int i=0; i < temppath.size(); i++) {
+        pwd2.concat( temppath[i].toPwSb() );
+        }
+
+    D2<Piecewise<SBasis> > d2pw = make_cuts_independant(pwd2);
+    boundingbox_X = bounds_exact(d2pw[0]);
+    boundingbox_Y = bounds_exact(d2pw[1]);
+    }    
+
+}
+
+
+Geom::Piecewise<Geom::D2<Geom::SBasis> >
+LPEBendPath::doEffect_pwd2 (Geom::Piecewise<Geom::D2<Geom::SBasis> > & pwd2_in)
+{
+    using namespace Geom;
+
+/* Much credit should go to jfb and mgsloan of lib2geom development for the code below! */
+
+    Piecewise<D2<SBasis> > uskeleton = arc_length_parametrization(Piecewise<D2<SBasis> >(bend_path.get_pwd2()),2,.1);
+    uskeleton = remove_short_cuts(uskeleton,.01);
+    Piecewise<D2<SBasis> > n = rot90(derivative(uskeleton));
+    n = force_continuity(remove_short_cuts(n,.1));
+
+    D2<Piecewise<SBasis> > patternd2 = make_cuts_independant(pwd2_in);
+    Piecewise<SBasis> x = vertical_pattern.get_value() ? Piecewise<SBasis>(patternd2[1]) : Piecewise<SBasis>(patternd2[0]);
+    Piecewise<SBasis> y = vertical_pattern.get_value() ? Piecewise<SBasis>(patternd2[0]) : Piecewise<SBasis>(patternd2[1]);
+
+//We use the group bounding box size or the path bbox size to translate well x and y 
+    if(groupSpecialBehavior == false)
+    {
+        boundingbox_X = bounds_exact(x);
+        boundingbox_Y = bounds_exact(y);
+    }
+    x-= boundingbox_X.min();
+    y-= boundingbox_Y.middle();
+
+  double scaling = uskeleton.cuts.back()/boundingbox_X.extent();
+
+  if (scaling != 1.0) {
+        x*=scaling;
+    }
+
+    if ( scale_y_rel.get_value() ) {
+        y*=(scaling*prop_scale);
+    } else {
+        if (prop_scale != 1.0) y *= prop_scale;
+    }
+
+
+    Piecewise<D2<SBasis> > output = compose(uskeleton,x) + y*compose(n,x);
+    return output;
+}
+
+void
+LPEBendPath::resetDefaults(SPItem * item)
+{
+    if (SP_IS_PATH(item) || SP_IS_GROUP(item))
+    {
+        // set the bend path to run horizontally in the middle of the bounding box of the original path
+        using namespace Geom;
+        Piecewise<D2<SBasis> > pwd2;
+        std::vector<Geom::Path> temppath;        
+
+        if (SP_IS_PATH(item))
+        {
+            //TODO : this won't work well with LPE stacking
+            temppath = SVGD_to_2GeomPath( SP_OBJECT_REPR(item)->attribute("inkscape:original-d"));
+        }
+        else if (SP_IS_GROUP(item))
+        {
+            recursive_original_bbox(SP_GROUP(item), pwd2, temppath);
+        }
+
+    for (unsigned int i=0; i < temppath.size(); i++) {
+        pwd2.concat( temppath[i].toPwSb() );
+        }
+
+    D2<Piecewise<SBasis> > d2pw = make_cuts_independant(pwd2);
+    boundingbox_X = bounds_exact(d2pw[0]);
+    boundingbox_Y = bounds_exact(d2pw[1]);
+
+
+    Point start(boundingbox_X.min(), (boundingbox_Y.max()+boundingbox_Y.min())/2);
+    Point end(boundingbox_X.max(), (boundingbox_Y.max()+boundingbox_Y.min())/2);
+
+    if ( Geom::are_near(start,end) ) {
+       end += Point(1.,0.);
+       }
+    Geom::Path path;
+    path.start( start );
+    path.appendNew<Geom::LineSegment>( end );
+    bend_path.param_set_and_write_new_value( path.toPwSb() );
+
+
+    }
+}
+
+void
+LPEBendPath::transform_multiply(Geom::Matrix const& postmul, bool set)
+{
+    // TODO: implement correct transformation instead of this default behavior
+    Effect::transform_multiply(postmul, set);
+}
+
+
+} // 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 :