1 files changed, 300 insertions, 0 deletions
diff --git a/src/live_effects/lpe-bendpath.cpp b/src/live_effects/lpe-bendpath.cpp
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+++ b/src/live_effects/lpe-bendpath.cpp
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+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) Johan Engelen 2007 <j.b.c.engelen@utwente.nl>
+ * Copyright (C) Steren Giannini 2008 <steren.giannini@gmail.com>
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include <vector>
+
+#include "display/curve.h"
+#include "live_effects/lpe-bendpath.h"
+#include "ui/knot/knot-holder.h"
+#include "ui/knot/knot-holder-entity.h"
+
+// TODO due to internal breakage in glibmm headers, this must be last:
+#include <glibmm/i18n.h>
+
+/* 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 {
+
+namespace BeP {
+class KnotHolderEntityWidthBendPath : public LPEKnotHolderEntity {
+    public:
+        KnotHolderEntityWidthBendPath(LPEBendPath * effect) : LPEKnotHolderEntity(effect) {}
+        ~KnotHolderEntityWidthBendPath() override
+        {
+            LPEBendPath *lpe = dynamic_cast<LPEBendPath *> (_effect);
+            lpe->_knot_entity = nullptr;
+        }
+        void knot_set(Geom::Point const &p, Geom::Point const &origin, guint state) override;
+        Geom::Point knot_get() const override;
+    };
+} // BeP
+
+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"),
+    original_height(0.0),
+    prop_scale(_("_Width:"), _("Width of the path"), "prop_scale", &wr, this, 1.0),
+    scale_y_rel(_("W_idth 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),
+    hide_knot(_("Hide width knot"), _("Hide width knot"),"hide_knot", &wr, this, false)
+{
+    registerParameter( &bend_path );
+    registerParameter( &prop_scale);
+    registerParameter( &scale_y_rel);
+    registerParameter( &vertical_pattern);
+    registerParameter(&hide_knot);
+
+    prop_scale.param_set_digits(3);
+    prop_scale.param_set_increments(0.01, 0.10);
+    
+    _knot_entity = nullptr;
+    _provides_knotholder_entities = true;
+    apply_to_clippath_and_mask = true;
+    concatenate_before_pwd2 = true;
+}
+
+LPEBendPath::~LPEBendPath()
+= default;
+
+
+bool 
+LPEBendPath::doOnOpen(SPLPEItem const *lpeitem)
+{
+    if (!is_load || is_applied) {
+        return false;
+    }
+    bend_path.reload();
+    return false;
+}
+
+
+void
+LPEBendPath::doBeforeEffect (SPLPEItem const* lpeitem)
+{
+    // get the item bounding box
+    original_bbox(lpeitem, false, true);
+    original_height = boundingbox_Y.max() - boundingbox_Y.min();
+    if (is_load) {
+        bend_path.reload();
+    }
+    if (_knot_entity) {
+        if (hide_knot) {
+            helper_path.clear();
+            _knot_entity->knot->hide();
+        } else {
+            _knot_entity->knot->show();
+        }
+        _knot_entity->update_knot();
+    }
+}
+
+void LPEBendPath::transform_multiply(Geom::Affine const &postmul, bool /*set*/)
+{   
+    Inkscape::Selection * selection = nullptr;
+    SPItem *linked = nullptr;
+    if (SP_ACTIVE_DESKTOP) {
+        selection = SP_ACTIVE_DESKTOP->getSelection();
+        linked = dynamic_cast<SPItem *>(bend_path.getObject());
+    }
+    if (linked) {
+        linked->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
+        return;
+    }
+    if (sp_lpe_item && sp_lpe_item->pathEffectsEnabled() && sp_lpe_item->optimizeTransforms()) {
+        bend_path.param_transform_multiply(postmul, false);
+    } else if( //this allow transform user spected way when lpeitem and pathparamenter are both selected
+        sp_lpe_item && 
+        sp_lpe_item->pathEffectsEnabled() &&
+        linked &&
+        (selection->includes(linked))) 
+    {
+        Geom::Affine transformlpeitem = sp_item_transform_repr(sp_lpe_item).inverse() * postmul;
+        sp_lpe_item->transform *= transformlpeitem.inverse();
+        sp_lpe_item->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
+    }
+}
+
+Geom::Piecewise<Geom::D2<Geom::SBasis> >
+LPEBendPath::doEffect_pwd2 (Geom::Piecewise<Geom::D2<Geom::SBasis> > const & pwd2_in)
+{
+    using namespace Geom;
+
+    /* Much credit should go to jfb and mgsloan of lib2geom development for the code below! */
+    Geom::Affine affine = bend_path.get_relative_affine();
+
+    if (bend_path.changed) {
+        uskeleton = arc_length_parametrization(Piecewise<D2<SBasis> >(bend_path.get_pwd2() * affine),2,.1);
+        uskeleton = remove_short_cuts(uskeleton,.01);
+        n = rot90(derivative(uskeleton));
+        n = force_continuity(remove_short_cuts(n,.01));
+
+        bend_path.changed = false;
+    }
+
+    if (uskeleton.empty()) {
+        return pwd2_in;  /// \todo or throw an exception instead? might be better to throw an exception so that the UI can display an error message or smth
+    }
+
+    D2<Piecewise<SBasis> > patternd2 = make_cuts_independent(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]);
+
+    Interval bboxHorizontal = vertical_pattern.get_value() ? boundingbox_Y : boundingbox_X;
+    Interval bboxVertical = vertical_pattern.get_value() ? boundingbox_X : boundingbox_Y;
+    
+    //+0.1 in x fix bug #1658855
+    //We use the group bounding box size or the path bbox size to translate well x and y
+    x-= bboxHorizontal.min() + 0.1;
+    y-= bboxVertical.middle();
+
+    double scaling = uskeleton.cuts.back()/bboxHorizontal.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 const* item)
+{
+    Effect::resetDefaults(item);
+    original_bbox(SP_LPE_ITEM(item), false, true);
+
+    Geom::Point start(boundingbox_X.min(), (boundingbox_Y.max()+boundingbox_Y.min())/2);
+    Geom::Point end(boundingbox_X.max(), (boundingbox_Y.max()+boundingbox_Y.min())/2);
+
+    if ( Geom::are_near(start,end) ) {
+        end += Geom::Point(1.,0.);
+    }
+     
+    Geom::Path path;
+    path.start( start );
+    path.appendNew<Geom::LineSegment>( end );
+    bend_path.set_new_value( path.toPwSb(), true );
+}
+
+void
+LPEBendPath::addCanvasIndicators(SPLPEItem const */*lpeitem*/, std::vector<Geom::PathVector> &hp_vec)
+{
+    hp_vec.push_back(helper_path);
+}
+
+void 
+LPEBendPath::addKnotHolderEntities(KnotHolder *knotholder, SPItem *item)
+{
+    _knot_entity = new BeP::KnotHolderEntityWidthBendPath(this);
+    _knot_entity->create(nullptr, item, knotholder, Inkscape::CANVAS_ITEM_CTRL_TYPE_LPE, "LPE:WidthBend",
+                         _("Change the width"));
+    knotholder->add(_knot_entity);
+    if (hide_knot) {
+        _knot_entity->knot->hide();
+        _knot_entity->update_knot();
+    }
+}
+
+namespace BeP {
+
+void 
+KnotHolderEntityWidthBendPath::knot_set(Geom::Point const &p, Geom::Point const& /*origin*/, guint state)
+{
+    LPEBendPath *lpe = dynamic_cast<LPEBendPath *> (_effect);
+
+    Geom::Point const s = snap_knot_position(p, state);
+    Geom::Path path_in = lpe->bend_path.get_pathvector().pathAt(Geom::PathVectorTime(0, 0, 0.0));
+    Geom::Point ptA = path_in.pointAt(Geom::PathTime(0, 0.0));
+    Geom::Point B = path_in.pointAt(Geom::PathTime(1, 0.0));
+    Geom::Curve const *first_curve = &path_in.curveAt(Geom::PathTime(0, 0.0));
+    Geom::CubicBezier const *cubic = dynamic_cast<Geom::CubicBezier const *>(&*first_curve);
+    Geom::Ray ray(ptA, B);
+    if (cubic) {
+        ray.setPoints(ptA, (*cubic)[1]);
+    }
+    ray.setAngle(ray.angle() + Geom::rad_from_deg(90));
+    Geom::Point knot_pos = this->knot->pos * item->i2dt_affine().inverse();
+    Geom::Coord nearest_to_ray = ray.nearestTime(knot_pos);
+    if(nearest_to_ray == 0){
+        lpe->prop_scale.param_set_value(-Geom::distance(s , ptA)/(lpe->original_height/2.0));
+    } else {
+        lpe->prop_scale.param_set_value(Geom::distance(s , ptA)/(lpe->original_height/2.0));
+    }
+    if (!lpe->original_height) {
+        lpe->prop_scale.param_set_value(0);
+    }
+    Inkscape::Preferences *prefs = Inkscape::Preferences::get();
+    prefs->setDouble("/live_effects/bend_path/width", lpe->prop_scale);
+
+    sp_lpe_item_update_patheffect (SP_LPE_ITEM(item), false, true);
+}
+
+Geom::Point 
+KnotHolderEntityWidthBendPath::knot_get() const
+{
+    LPEBendPath *lpe = dynamic_cast<LPEBendPath *> (_effect);
+    Geom::Path path_in = lpe->bend_path.get_pathvector().pathAt(Geom::PathVectorTime(0, 0, 0.0));
+    Geom::Point ptA = path_in.pointAt(Geom::PathTime(0, 0.0));
+    Geom::Point B = path_in.pointAt(Geom::PathTime(1, 0.0));
+    Geom::Curve const *first_curve = &path_in.curveAt(Geom::PathTime(0, 0.0));
+    Geom::CubicBezier const *cubic = dynamic_cast<Geom::CubicBezier const *>(&*first_curve);
+    Geom::Ray ray(ptA, B);
+    if (cubic) {
+        ray.setPoints(ptA, (*cubic)[1]);
+    }
+    ray.setAngle(ray.angle() + Geom::rad_from_deg(90));
+    Geom::Point result_point = Geom::Point::polar(ray.angle(), (lpe->original_height/2.0) * lpe->prop_scale) + ptA;
+    lpe->helper_path.clear();
+    if (!lpe->hide_knot) {
+        Geom::Path hp(result_point);
+        hp.appendNew<Geom::LineSegment>(ptA);
+        lpe->helper_path.push_back(hp);
+        hp.clear();
+    }
+    return result_point;
+}
+} // namespace BeP
+} // 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 :