1 files changed, 121 insertions, 0 deletions
diff --git a/src/live_effects/lpe-recursiveskeleton.cpp b/src/live_effects/lpe-recursiveskeleton.cpp
new file mode 100644
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+++ b/src/live_effects/lpe-recursiveskeleton.cpp
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+// SPDX-License-Identifier: GPL-2.0-or-later
+/**
+ * @file
+ * Inspired by Hofstadter's 'Goedel Escher Bach', chapter V.
+ */
+/* Authors:
+ *   Johan Engelen <j.b.c.engelen@utwente.nl>
+ *
+ * Copyright (C) 2007-2009 Authors
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include "live_effects/lpe-recursiveskeleton.h"
+
+#include <2geom/bezier-to-sbasis.h>
+
+// TODO due to internal breakage in glibmm headers, this must be last:
+#include <glibmm/i18n.h>
+
+namespace Inkscape {
+namespace LivePathEffect {
+
+LPERecursiveSkeleton::LPERecursiveSkeleton(LivePathEffectObject *lpeobject) :
+    Effect(lpeobject),
+    iterations(_("Iterations:"), _("recursivity"), "iterations", &wr, this, 2)
+{
+    show_orig_path = true;
+    concatenate_before_pwd2 = true;
+    iterations.param_make_integer(true);
+    iterations.param_set_range(1, 15);
+    registerParameter(&iterations);
+
+}
+
+LPERecursiveSkeleton::~LPERecursiveSkeleton()
+= default;
+
+
+Geom::Piecewise<Geom::D2<Geom::SBasis> >
+LPERecursiveSkeleton::doEffect_pwd2 (Geom::Piecewise<Geom::D2<Geom::SBasis> > const & pwd2_in)
+{
+    using namespace Geom;
+
+    Piecewise<D2<SBasis> > output;
+    double prop_scale = 1.0;
+
+    D2<Piecewise<SBasis> > patternd2 = make_cuts_independent(pwd2_in);
+    Piecewise<SBasis> x0 = false /*vertical_pattern.get_value()*/ ? Piecewise<SBasis>(patternd2[1]) : Piecewise<SBasis>(patternd2[0]);
+    Piecewise<SBasis> y0 = false /*vertical_pattern.get_value()*/ ? Piecewise<SBasis>(patternd2[0]) : Piecewise<SBasis>(patternd2[1]);
+    OptInterval pattBndsX = bounds_exact(x0);
+    OptInterval pattBndsY = bounds_exact(y0);
+
+    if ( !pattBndsX || !pattBndsY) {
+        return pwd2_in;
+    }
+
+    x0 -= pattBndsX->min();
+    y0 -= pattBndsY->middle();
+
+    double noffset = 0;//normal_offset;
+    double toffset = 0;//tang_offset;
+    if (false /*prop_units.get_value()*/){
+        noffset *= pattBndsY->extent();
+        toffset *= pattBndsX->extent();
+    }
+
+    y0+=noffset;
+
+    output = pwd2_in;
+
+    for (int i = 0; i < iterations; ++i) {
+        std::vector<Piecewise<D2<SBasis> > > skeleton = split_at_discontinuities(output);
+
+        output.clear();
+        for (auto path_i : skeleton){
+            Piecewise<SBasis> x = x0;
+            Piecewise<SBasis> y = y0;
+            Piecewise<D2<SBasis> > uskeleton = arc_length_parametrization(path_i,2,.1);
+            uskeleton = remove_short_cuts(uskeleton,.01);
+            Piecewise<D2<SBasis> > n = rot90(derivative(uskeleton));
+            n = force_continuity(remove_short_cuts(n,.1));
+
+            double scaling = (uskeleton.domain().extent() - toffset)/pattBndsX->extent();
+
+            // TODO investigate why pattWidth is not being used:
+            // - Doesn't appear to have been used anywhere in bzr history (Alex V: 2013-03-16)
+            // double pattWidth = pattBndsX->extent() * scaling;
+
+            if (scaling != 1.0) {
+                x*=scaling;
+            }
+
+            if ( true /*scale_y_rel.get_value()*/ ) {
+                y*=(scaling*prop_scale);
+            } else {
+                if (prop_scale != 1.0) y *= prop_scale;
+            }
+            x += toffset;
+
+            output.concat(compose(uskeleton,x)+y*compose(n,x));
+        }
+    }
+
+    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:fileencoding=utf-8:textwidth=99 :