1 files changed, 215 insertions, 0 deletions
diff --git a/src/live_effects/lpe-curvestitch.cpp b/src/live_effects/lpe-curvestitch.cpp
new file mode 100644
index 0000000..f1f74dd
--- /dev/null
+++ b/src/live_effects/lpe-curvestitch.cpp
@@ -0,0 +1,215 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/** \file
+ * LPE Curve Stitching implementation, used as an example for a base starting class
+ * when implementing new LivePathEffects.
+ *
+ */
+/*
+ * Authors:
+ *   Johan Engelen
+ *
+ * Copyright (C) Johan Engelen 2007 <j.b.c.engelen@utwente.nl>
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include "ui/widget/scalar.h"
+#include "live_effects/lpe-curvestitch.h"
+
+#include "object/sp-path.h"
+
+#include "svg/svg.h"
+#include "xml/repr.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 {
+
+using namespace Geom;
+
+LPECurveStitch::LPECurveStitch(LivePathEffectObject *lpeobject) :
+    Effect(lpeobject),
+    strokepath(_("Stitch path:"), _("The path that will be used as stitch."), "strokepath", &wr, this, "M0,0 L1,0"),
+    nrofpaths(_("N_umber of paths:"), _("The number of paths that will be generated."), "count", &wr, this, 5),
+    startpoint_edge_variation(_("Sta_rt edge variance:"), _("The amount of random jitter to move the start points of the stitches inside & outside the guide path"), "startpoint_edge_variation", &wr, this, 0),
+    startpoint_spacing_variation(_("Sta_rt spacing variance:"), _("The amount of random shifting to move the start points of the stitches back & forth along the guide path"), "startpoint_spacing_variation", &wr, this, 0),
+    endpoint_edge_variation(_("End ed_ge variance:"), _("The amount of randomness that moves the end points of the stitches inside & outside the guide path"), "endpoint_edge_variation", &wr, this, 0),
+    endpoint_spacing_variation(_("End spa_cing variance:"), _("The amount of random shifting to move the end points of the stitches back & forth along the guide path"), "endpoint_spacing_variation", &wr, this, 0),
+    prop_scale(_("Scale _width:"), _("Scale the width of the stitch path"), "prop_scale", &wr, this, 1),
+    scale_y_rel(_("Scale _width relative to length"), _("Scale the width of the stitch path relative to its length"), "scale_y_rel", &wr, this, false)
+{
+    registerParameter(&nrofpaths);
+    registerParameter(&startpoint_edge_variation);
+    registerParameter(&startpoint_spacing_variation);
+    registerParameter(&endpoint_edge_variation);
+    registerParameter(&endpoint_spacing_variation);
+    registerParameter(&strokepath );
+    registerParameter(&prop_scale);
+    registerParameter(&scale_y_rel);
+
+    nrofpaths.param_make_integer();
+    nrofpaths.param_set_range(2, Geom::infinity());
+
+    prop_scale.param_set_digits(3);
+    prop_scale.param_set_increments(0.01, 0.10);
+    transformed = false;
+}
+
+LPECurveStitch::~LPECurveStitch()
+= default;
+
+bool 
+LPECurveStitch::doOnOpen(SPLPEItem const *lpeitem)
+{
+    if (!is_load || is_applied) {
+        return false;
+    }
+    strokepath.reload();
+    return false;
+}
+
+
+Geom::PathVector
+LPECurveStitch::doEffect_path (Geom::PathVector const & path_in)
+{
+
+    if (is_load) {
+        strokepath.reload();
+    }
+
+    if (path_in.size() >= 2) {
+        startpoint_edge_variation.resetRandomizer();
+        endpoint_edge_variation.resetRandomizer();
+        startpoint_spacing_variation.resetRandomizer();
+        endpoint_spacing_variation.resetRandomizer();
+        Geom::Affine affine = strokepath.get_relative_affine().withoutTranslation();
+
+        D2<Piecewise<SBasis> > stroke = make_cuts_independent(strokepath.get_pwd2() * affine);
+        OptInterval bndsStroke = bounds_exact(stroke[0]);
+        OptInterval bndsStrokeY = bounds_exact(stroke[1]);
+        if (!bndsStroke && !bndsStrokeY) {
+            return path_in;
+        }
+        gdouble scaling = bndsStroke->max() - bndsStroke->min();
+        Point stroke_origin(bndsStroke->min(), (bndsStrokeY->max()+bndsStrokeY->min())/2);
+
+        Geom::PathVector path_out;
+
+        // do this for all permutations (ii,jj) if there are more than 2 paths? realllly cool!
+        for (unsigned ii = 0   ; ii < path_in.size() - 1; ii++)
+        for (unsigned jj = ii+1; jj < path_in.size(); jj++)
+        {
+            Piecewise<D2<SBasis> > A = arc_length_parametrization(Piecewise<D2<SBasis> >(path_in[ii].toPwSb()),2,.1);
+            Piecewise<D2<SBasis> > B = arc_length_parametrization(Piecewise<D2<SBasis> >(path_in[jj].toPwSb()),2,.1);
+            Interval bndsA = A.domain();
+            Interval bndsB = B.domain();
+            gdouble incrementA = (bndsA.max()-bndsA.min()) / (nrofpaths-1);
+            gdouble incrementB = (bndsB.max()-bndsB.min()) / (nrofpaths-1);
+            gdouble tA = bndsA.min();
+            gdouble tB = bndsB.min();
+            gdouble tAclean = tA; // the tA without spacing_variation
+            gdouble tBclean = tB; // the tB without spacing_variation
+
+            for (int i = 0; i < nrofpaths; i++) {
+                Point start = A(tA);
+                Point end = B(tB);
+                if (startpoint_edge_variation.get_value() != 0)
+                    start = start + (startpoint_edge_variation - startpoint_edge_variation.get_value()/2) * (end - start);
+                if (endpoint_edge_variation.get_value() != 0)
+                    end = end + (endpoint_edge_variation - endpoint_edge_variation.get_value()/2)* (end - start);
+        
+                if (!Geom::are_near(start,end)) {
+                    gdouble scaling_y = 1.0;
+                    if (scale_y_rel.get_value() || transformed) {
+                        scaling_y = (L2(end-start)/scaling)*prop_scale;
+                        transformed = false;
+                    } else {
+                        scaling_y = prop_scale;
+                    }
+
+                    Affine transform;
+                    transform.setXAxis( (end-start) / scaling );
+                    transform.setYAxis( rot90(unit_vector(end-start)) * scaling_y);
+                    transform.setTranslation( start );
+                    Piecewise<D2<SBasis> > pwd2_out = (strokepath.get_pwd2()-stroke_origin) * transform;
+
+                    // add stuff to one big pw<d2<sbasis> > and then outside the loop convert to path?
+                    // No: this way, the separate result paths are kept separate which might come in handy some time!
+                    Geom::PathVector result = Geom::path_from_piecewise(pwd2_out, LPE_CONVERSION_TOLERANCE);
+                    path_out.push_back(result[0]);
+                }
+                gdouble svA = startpoint_spacing_variation - startpoint_spacing_variation.get_value()/2;
+                gdouble svB = endpoint_spacing_variation - endpoint_spacing_variation.get_value()/2;
+                tAclean += incrementA;
+                tBclean += incrementB;
+                tA = tAclean + incrementA * svA;
+                tB = tBclean + incrementB * svB;
+                if (tA > bndsA.max())
+                    tA = bndsA.max();
+                if (tB > bndsB.max())
+                    tB = bndsB.max();
+            }
+        }
+
+        return path_out;
+    } else {
+        return path_in;
+    }
+}
+
+void
+LPECurveStitch::resetDefaults(SPItem const* item)
+{
+    Effect::resetDefaults(item);
+
+    if (!SP_IS_PATH(item)) return;
+
+    using namespace Geom;
+
+    // set the stroke path to run horizontally in the middle of the bounding box of the original path
+    
+    // calculate bounding box:  (isn't there a simpler way?)
+    Piecewise<D2<SBasis> > pwd2;
+    Geom::PathVector temppath = sp_svg_read_pathv( item->getRepr()->attribute("inkscape:original-d"));
+    for (const auto & i : temppath) {
+        pwd2.concat( i.toPwSb() );
+    }
+    D2<Piecewise<SBasis> > d2pw = make_cuts_independent(pwd2);
+    OptInterval bndsX = bounds_exact(d2pw[0]);
+    OptInterval bndsY = bounds_exact(d2pw[1]);
+    if (bndsX && bndsY) {
+        Point start(bndsX->min(), (bndsY->max()+bndsY->min())/2);
+        Point end(bndsX->max(), (bndsY->max()+bndsY->min())/2);
+        if ( !Geom::are_near(start,end) ) {
+            Geom::Path path;
+            path.start( start );
+            path.appendNew<Geom::LineSegment>( end );
+            strokepath.set_new_value( path.toPwSb(), true );
+        } else {
+            // bounding box is too small to make decent path. set to default default. :-)
+            strokepath.param_set_and_write_default();
+        }
+    } else {
+        // bounding box is non-existent. set to default default. :-)
+        strokepath.param_set_and_write_default();
+    }
+}
+
+} //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 :