Adding upstream version 1.2.2.upstream/1.2.2upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 590 insertions, 0 deletions

diff --git a/src/live_effects/lpe-taperstroke.cpp b/src/live_effects/lpe-taperstroke.cpp
new file mode 100644
index 0000000..f78012e
--- /dev/null
+++ b/src/live_effects/lpe-taperstroke.cpp
@@ -0,0 +1,590 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/**
+ * @file
+ * Taper Stroke path effect, provided as an alternative to Power Strokes
+ * for otherwise constant-width paths.
+ *
+ * Authors:
+ *   Liam P White
+ *
+ * Copyright (C) 2014-2020 Authors
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include "live_effects/lpe-taperstroke.h"
+#include "live_effects/fill-conversion.h"
+
+#include <2geom/circle.h>
+#include <2geom/sbasis-to-bezier.h>
+
+#include "style.h"
+
+#include "display/curve.h"
+#include "helper/geom-nodetype.h"
+#include "helper/geom-pathstroke.h"
+#include "object/sp-shape.h"
+#include "svg/svg-color.h"
+#include "svg/css-ostringstream.h"
+#include "svg/svg.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>
+
+template<typename T>
+inline bool withinRange(T value, T low, T high) {
+    return (value > low && value < high);
+}
+
+namespace Inkscape {
+namespace LivePathEffect {
+
+namespace TpS {
+    class KnotHolderEntityAttachBegin : public LPEKnotHolderEntity {
+    public:
+        KnotHolderEntityAttachBegin(LPETaperStroke * effect) : LPEKnotHolderEntity(effect) {}
+        void knot_set(Geom::Point const &p, Geom::Point const &origin, guint state) override;
+        void knot_click(guint state) override;
+        Geom::Point knot_get() const override;
+    };
+    
+    class KnotHolderEntityAttachEnd : public LPEKnotHolderEntity {
+    public:
+        KnotHolderEntityAttachEnd(LPETaperStroke * effect) : LPEKnotHolderEntity(effect) {}
+        void knot_set(Geom::Point const &p, Geom::Point const &origin, guint state) override;
+        void knot_click(guint state) override;
+        Geom::Point knot_get() const override;
+    };
+} // TpS
+
+static const Util::EnumData<unsigned> JoinType[] = {
+    // clang-format off
+    {JOIN_BEVEL,          N_("Beveled"),         "bevel"},
+    {JOIN_ROUND,          N_("Rounded"),         "round"},
+    {JOIN_MITER,          N_("Miter"),           "miter"},
+    {JOIN_EXTRAPOLATE,    N_("Extrapolated"),    "extrapolated"},
+    // clang-format on
+};
+
+enum TaperShape {
+    TAPER_CENTER,
+    TAPER_RIGHT,
+    TAPER_LEFT,
+    LAST_SHAPE
+};
+
+static const Util::EnumData<unsigned> TaperShapeType[] = {
+    {TAPER_CENTER, N_("Center"), "center"},
+    {TAPER_LEFT,   N_("Left"),   "left"},
+    {TAPER_RIGHT,  N_("Right"),  "right"},
+};
+
+static const Util::EnumDataConverter<unsigned> JoinTypeConverter(JoinType, sizeof (JoinType)/sizeof(*JoinType));
+static const Util::EnumDataConverter<unsigned> TaperShapeTypeConverter(TaperShapeType, sizeof (TaperShapeType)/sizeof(*TaperShapeType));
+
+LPETaperStroke::LPETaperStroke(LivePathEffectObject *lpeobject) :
+    Effect(lpeobject),
+    line_width(_("Stroke width:"), _("The (non-tapered) width of the path"), "stroke_width", &wr, this, 1.),
+    attach_start(_("Start offset:"), _("Taper distance from path start"), "attach_start", &wr, this, 0.2),
+    attach_end(_("End offset:"), _("The ending position of the taper"), "end_offset", &wr, this, 0.2),
+    start_smoothing(_("Start smoothing:"), _("Amount of smoothing to apply to the start taper"), "start_smoothing", &wr, this, 0.5),
+    end_smoothing(_("End smoothing:"), _("Amount of smoothing to apply to the end taper"), "end_smoothing", &wr, this, 0.5),
+    join_type(_("Join type:"), _("Join type for non-smooth nodes"), "jointype", JoinTypeConverter, &wr, this, JOIN_EXTRAPOLATE),
+    start_shape(_("Start direction:"), _("Direction of the taper at the path start"), "start_shape", TaperShapeTypeConverter, &wr, this, TAPER_CENTER),
+    end_shape(_("End direction:"), _("Direction of the taper at the path end"), "end_shape", TaperShapeTypeConverter, &wr, this, TAPER_CENTER),
+    miter_limit(_("Miter limit:"), _("Limit for miter joins"), "miter_limit", &wr, this, 100.)
+{
+    show_orig_path = true;
+    _provides_knotholder_entities = true;
+
+    attach_start.param_set_digits(3);
+    attach_end.param_set_digits(3);
+
+    registerParameter(&line_width);
+    registerParameter(&attach_start);
+    registerParameter(&attach_end);
+    registerParameter(&start_smoothing);
+    registerParameter(&end_smoothing);
+    registerParameter(&join_type);
+    registerParameter(&start_shape);
+    registerParameter(&end_shape);
+    registerParameter(&miter_limit);
+}
+
+// from LPEPowerStroke -- sets fill if stroke color because we will
+// be converting to a fill to make the new join.
+
+void LPETaperStroke::transform_multiply(Geom::Affine const &postmul, bool /*set*/)
+{
+    Inkscape::Preferences *prefs = Inkscape::Preferences::get();
+    bool transform_stroke = prefs ? prefs->getBool("/options/transform/stroke", true) : true;
+    if (transform_stroke) {
+        line_width.param_transform_multiply(postmul, false);
+    }
+}
+
+void LPETaperStroke::doOnApply(SPLPEItem const* lpeitem)
+{
+    auto lpeitem_mutable = const_cast<SPLPEItem *>(lpeitem);
+    auto item = dynamic_cast<SPShape *>(lpeitem_mutable);
+
+    if (!item) {
+        printf("WARNING: It only makes sense to apply Taper stroke to paths (not groups).\n");
+    }
+
+    Inkscape::Preferences *prefs = Inkscape::Preferences::get();
+
+    double width = (lpeitem && lpeitem->style) ? lpeitem->style->stroke_width.computed : 1.;
+
+    lpe_shape_convert_stroke_and_fill(item);
+
+    Glib::ustring pref_path = (Glib::ustring)"/live_effects/" +
+                                    (Glib::ustring)LPETypeConverter.get_key(effectType()).c_str() +
+                                    (Glib::ustring)"/" + 
+                                    (Glib::ustring)"stroke_width";
+
+    bool valid = prefs->getEntry(pref_path).isValid();
+
+    if (!valid) {
+        line_width.param_set_value(width);
+    }
+
+    line_width.write_to_SVG();
+}
+
+void LPETaperStroke::doOnRemove(SPLPEItem const* lpeitem)
+{
+    auto lpeitem_mutable = const_cast<SPLPEItem *>(lpeitem);
+    auto item = dynamic_cast<SPShape *>(lpeitem_mutable);
+
+    if (!item) {
+        return;
+    }
+
+    lpe_shape_revert_stroke_and_fill(item, line_width);
+}
+
+using Geom::Piecewise;
+using Geom::D2;
+using Geom::SBasis;
+// leave Geom::Path
+
+static Geom::Path return_at_first_cusp(Geom::Path const & path_in, double /*smooth_tolerance*/ = 0.05)
+{
+    Geom::Path temp;
+
+    for (unsigned i = 0; i < path_in.size(); i++) {
+        temp.append(path_in[i]);
+        if (path_in.size() > i+1) {
+            if (Geom::get_nodetype(path_in[i], path_in[i + 1]) != Geom::NODE_SMOOTH ) {
+                break;
+            }
+        }
+    }
+    
+    return temp;
+}
+
+Piecewise<D2<SBasis> > stretch_along(Piecewise<D2<SBasis> > pwd2_in, Geom::Path pattern, double width);
+
+// actual effect
+
+Geom::PathVector LPETaperStroke::doEffect_path(Geom::PathVector const& path_in)
+{
+    Geom::Path first_cusp = return_at_first_cusp(path_in[0]);
+    Geom::Path last_cusp = return_at_first_cusp(path_in[0].reversed());
+
+    bool zeroStart = false; // [distance from start taper knot -> start of path] == 0
+    bool zeroEnd = false; // [distance from end taper knot -> end of path] == 0
+    bool metInMiddle = false; // knots are touching
+    
+    // there is a pretty good chance that people will try to drag the knots
+    // on top of each other, so block it
+
+    unsigned size = path_in[0].size();
+    if (size == first_cusp.size()) {
+        // check to see if the knots were dragged over each other
+        // if so, reset the end offset, but still allow the start offset.
+        if ( attach_start >= (size - attach_end) ) {
+            attach_end.param_set_value( size - attach_start );
+            metInMiddle = true;
+        }
+    }
+    
+    if (attach_start == size - attach_end) {
+        metInMiddle = true;
+    }
+    if (attach_end == size - attach_start) {
+        metInMiddle = true;
+    }
+
+    // don't let it be integer (TODO this is stupid!)
+    {
+        if (double(unsigned(attach_start)) == attach_start) {
+            attach_start.param_set_value(attach_start - 0.00001);
+        }
+        if (double(unsigned(attach_end)) == attach_end) {
+            attach_end.param_set_value(attach_end -     0.00001);
+        }
+    }
+
+    unsigned allowed_start = first_cusp.size();
+    unsigned allowed_end = last_cusp.size();
+
+    // don't let the knots be farther than they are allowed to be
+    {
+        if ((unsigned)attach_start >= allowed_start) {
+            attach_start.param_set_value((double)allowed_start - 0.00001);
+        }
+        if ((unsigned)attach_end >= allowed_end) {
+            attach_end.param_set_value((double)allowed_end - 0.00001);
+        }
+    }
+    
+    // don't let it be zero (this is stupid too!)
+    if (attach_start < 0.0000001 || withinRange(double(attach_start), 0.00000001, 0.000001)) {
+        attach_start.param_set_value( 0.0000001 );
+        zeroStart = true;
+    }
+    if (attach_end < 0.0000001 || withinRange(double(attach_end), 0.00000001, 0.000001)) {
+        attach_end.param_set_value( 0.0000001 );
+        zeroEnd = true;
+    }
+
+    // Path::operator () means get point at time t
+    start_attach_point = first_cusp(attach_start);
+    end_attach_point = last_cusp(attach_end);
+    Geom::PathVector pathv_out;
+
+    // the following function just splits it up into three pieces.
+    pathv_out = doEffect_simplePath(path_in);
+
+    // now for the actual tapering. the stretch_along method (stolen from PaP) is used to accomplish this
+
+    Geom::PathVector real_pathv;
+    Geom::Path real_path;
+    Geom::PathVector pat_vec;
+    Piecewise<D2<SBasis> > pwd2;
+    Geom::Path throwaway_path;
+
+    if (!zeroStart) {
+        // Construct the pattern
+        std::stringstream pat_str;
+        pat_str.imbue(std::locale::classic());
+
+        switch (start_shape.get_value()) {
+            case TAPER_RIGHT:
+                pat_str << "M 1,0 Q " << 1 - (double)start_smoothing << ",0 0,1 L 1,1";
+                break;
+            case TAPER_LEFT:
+                pat_str << "M 1,0 L 0,0 Q " << 1 - (double)start_smoothing << ",1 1,1";
+                break;
+            default:
+                pat_str << "M 1,0 C " << 1 - (double)start_smoothing << ",0 0,0.5 0,0.5 0,0.5 " << 1 - (double)start_smoothing << ",1 1,1";
+                break;
+        }
+
+        pat_vec = sp_svg_read_pathv(pat_str.str().c_str());
+        pwd2.concat(stretch_along(pathv_out[0].toPwSb(), pat_vec[0], fabs(line_width)));
+        throwaway_path = Geom::path_from_piecewise(pwd2, LPE_CONVERSION_TOLERANCE)[0];
+
+        real_path.append(throwaway_path);
+    }
+    
+    // if this condition happens to evaluate false, i.e. there was no space for a path to be drawn, it is simply skipped.
+    // although this seems obvious, it can probably lead to bugs.
+    if (!metInMiddle) {
+        // append the outside outline of the path (goes with the direction of the path)
+        throwaway_path = half_outline(pathv_out[1], fabs(line_width)/2., miter_limit, static_cast<LineJoinType>(join_type.get_value()));
+        if (!zeroStart && real_path.size() >= 1 && throwaway_path.size() >= 1) {
+            if (!Geom::are_near(real_path.finalPoint(), throwaway_path.initialPoint())) {
+                real_path.appendNew<Geom::LineSegment>(throwaway_path.initialPoint());
+            } else {
+                real_path.setFinal(throwaway_path.initialPoint());
+            }
+        }
+        real_path.append(throwaway_path);
+    }
+
+    if (!zeroEnd) {
+        // append the ending taper
+        std::stringstream pat_str_1;
+        pat_str_1.imbue(std::locale::classic());
+
+        switch (end_shape.get_value()) {
+            case TAPER_RIGHT:
+                pat_str_1 << "M 0,1 L 1,1 Q " << (double)end_smoothing << ",0 0,0";
+                break;
+            case TAPER_LEFT:
+                pat_str_1 << "M 0,1 Q " << (double)end_smoothing << ",1 1,0 L 0,0";
+                break;
+            default:
+                pat_str_1 << "M 0,1 C " << (double)end_smoothing << ",1 1,0.5 1,0.5 1,0.5 " << (double)end_smoothing << ",0 0,0";
+                break;
+        }
+
+        pat_vec = sp_svg_read_pathv(pat_str_1.str().c_str());
+
+        pwd2 = Piecewise<D2<SBasis> >();
+        pwd2.concat(stretch_along(pathv_out[2].toPwSb(), pat_vec[0], fabs(line_width)));
+
+        throwaway_path = Geom::path_from_piecewise(pwd2, LPE_CONVERSION_TOLERANCE)[0];
+        if (!Geom::are_near(real_path.finalPoint(), throwaway_path.initialPoint()) && real_path.size() >= 1) {
+            real_path.appendNew<Geom::LineSegment>(throwaway_path.initialPoint());
+        } else {
+            real_path.setFinal(throwaway_path.initialPoint());
+        }
+        real_path.append(throwaway_path);
+    }
+    
+    if (!metInMiddle) {
+        // append the inside outline of the path (against direction)
+        throwaway_path = half_outline(pathv_out[1].reversed(), fabs(line_width)/2., miter_limit, static_cast<LineJoinType>(join_type.get_value()));
+        
+        if (!Geom::are_near(real_path.finalPoint(), throwaway_path.initialPoint()) && real_path.size() >= 1) {
+            real_path.appendNew<Geom::LineSegment>(throwaway_path.initialPoint());
+        } else {
+            real_path.setFinal(throwaway_path.initialPoint());
+        }
+        real_path.append(throwaway_path);
+    }
+    
+    if (!Geom::are_near(real_path.finalPoint(), real_path.initialPoint())) {
+        real_path.appendNew<Geom::LineSegment>(real_path.initialPoint());
+    } else {
+        real_path.setFinal(real_path.initialPoint());
+    }
+    real_path.close();
+    
+    real_pathv.push_back(real_path);
+
+    return real_pathv;
+}
+
+/**
+ * @return Always returns a PathVector with three elements.
+ *
+ *  The positions of the effect knots are accessed to determine
+ *  where exactly the input path should be split.
+ */
+Geom::PathVector LPETaperStroke::doEffect_simplePath(Geom::PathVector const & path_in)
+{
+    Geom::Coord endTime = path_in[0].size() - attach_end;
+
+    Geom::Path p1 = path_in[0].portion(0., attach_start);
+    Geom::Path p2 = path_in[0].portion(attach_start, endTime);
+    Geom::Path p3 = path_in[0].portion(endTime, path_in[0].size());
+    
+    Geom::PathVector out;
+    out.push_back(p1);
+    out.push_back(p2);
+    out.push_back(p3);
+    
+    return out;
+}
+
+
+/**
+ * Most of the below function is verbatim from Pattern Along Path. However, it needed a little
+ * tweaking to get it to work right in this case. Also, large portions of the effect have been
+ * stripped out as I deemed them unnecessary for the relative simplicity of this effect.
+ */
+Piecewise<D2<SBasis> > stretch_along(Piecewise<D2<SBasis> > pwd2_in, Geom::Path pattern, double prop_scale)
+{
+    using namespace Geom;
+
+    // Don't allow empty path parameter:
+    if ( pattern.empty() ) {
+        return pwd2_in;
+    }
+
+    /* Much credit should go to jfb and mgsloan of lib2geom development for the code below! */
+    Piecewise<D2<SBasis> > output;
+    std::vector<Piecewise<D2<SBasis> > > pre_output;
+
+    D2<Piecewise<SBasis> > patternd2 = make_cuts_independent(pattern.toPwSb());
+    Piecewise<SBasis> x0 = Piecewise<SBasis>(patternd2[0]);
+    Piecewise<SBasis> y0 = Piecewise<SBasis>(patternd2[1]);
+    OptInterval pattBndsX = bounds_exact(x0);
+    OptInterval pattBndsY = bounds_exact(y0);
+    if (pattBndsX && pattBndsY) {
+        x0 -= pattBndsX->min();
+        y0 -= pattBndsY->middle();
+
+        double noffset = 0;
+        double toffset = 0;
+        // Prevent more than 90% overlap...
+
+        y0+=noffset;
+
+        std::vector<Piecewise<D2<SBasis> > > paths_in;
+        paths_in = split_at_discontinuities(pwd2_in);
+
+        for (auto path_i : paths_in) {
+            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));
+
+            int nbCopies = 0;
+            double scaling = (uskeleton.domain().extent() - toffset)/pattBndsX->extent();
+            nbCopies = 1;
+
+            double pattWidth = pattBndsX->extent() * scaling;
+
+            if (scaling != 1.0) {
+                x*=scaling;
+            }
+            if ( false ) {
+                y*=(scaling*prop_scale);
+            } else {
+                if (prop_scale != 1.0) y *= prop_scale;
+            }
+            x += toffset;
+
+            double offs = 0;
+            for (int i=0; i<nbCopies; i++) {
+                if (false) {
+                    Piecewise<D2<SBasis> > output_piece = compose(uskeleton,x+offs)+y*compose(n,x+offs);
+                    std::vector<Piecewise<D2<SBasis> > > splited_output_piece = split_at_discontinuities(output_piece);
+                    pre_output.insert(pre_output.end(), splited_output_piece.begin(), splited_output_piece.end() );
+                } else {
+                    output.concat(compose(uskeleton,x+offs)+y*compose(n,x+offs));
+                }
+                offs+=pattWidth;
+            }
+        }
+        return output;
+    } else {
+        return pwd2_in;
+    }
+}
+
+void LPETaperStroke::addKnotHolderEntities(KnotHolder *knotholder, SPItem *item)
+{
+    KnotHolderEntity *e = new TpS::KnotHolderEntityAttachBegin(this);
+    e->create(nullptr, item, knotholder, Inkscape::CANVAS_ITEM_CTRL_TYPE_LPE, "LPE:TaperStrokeBegin",
+              _("<b>Start point of the taper</b>: drag to alter the taper, <b>Shift+click</b> changes the taper direction"));
+    knotholder->add(e);
+
+    KnotHolderEntity *f = new TpS::KnotHolderEntityAttachEnd(this);
+    f->create(nullptr, item, knotholder, Inkscape::CANVAS_ITEM_CTRL_TYPE_LPE, "LPE:TaperStrokeEnd",
+              _("<b>End point of the taper</b>: drag to alter the taper, <b>Shift+click</b> changes the taper direction"));
+    knotholder->add(f);
+}
+
+namespace TpS {
+
+void KnotHolderEntityAttachBegin::knot_set(Geom::Point const &p, Geom::Point const&/*origin*/, guint state)
+{
+    using namespace Geom;
+
+    LPETaperStroke* lpe = dynamic_cast<LPETaperStroke *>(_effect);
+
+    Geom::Point const s = snap_knot_position(p, state);
+
+    if (!SP_IS_SHAPE(lpe->sp_lpe_item)) {
+        printf("WARNING: LPEItem is not a path!\n");
+        return;
+    }
+    
+    if (!SP_SHAPE(lpe->sp_lpe_item)->curve()) {
+        // oops
+        return;
+    }
+    // in case you are wondering, the above are simply sanity checks. we never want to actually
+    // use that object.
+    
+    Geom::PathVector pathv = lpe->pathvector_before_effect;
+    Piecewise<D2<SBasis> > pwd2;
+    Geom::Path p_in = return_at_first_cusp(pathv[0]);
+    pwd2.concat(p_in.toPwSb());
+
+    double t0 = nearest_time(s, pwd2);
+    lpe->attach_start.param_set_value(t0);
+
+    // FIXME: this should not directly ask for updating the item. It should write to SVG, which triggers updating.
+    sp_lpe_item_update_patheffect(SP_LPE_ITEM(item), false, true);
+}
+
+void KnotHolderEntityAttachBegin::knot_click(guint state)
+{
+    if (!(state & GDK_SHIFT_MASK)) {
+        return;
+    }
+
+    LPETaperStroke* lpe = dynamic_cast<LPETaperStroke *>(_effect);
+
+    lpe->start_shape.param_set_value((lpe->start_shape.get_value() + 1) % LAST_SHAPE);
+    lpe->start_shape.write_to_SVG();
+}
+
+void KnotHolderEntityAttachEnd::knot_click(guint state)
+{
+    if (!(state & GDK_SHIFT_MASK)) {
+        return;
+    }
+
+    LPETaperStroke* lpe = dynamic_cast<LPETaperStroke *>(_effect);
+
+    lpe->end_shape.param_set_value((lpe->end_shape.get_value() + 1) % LAST_SHAPE);
+    lpe->end_shape.write_to_SVG();
+}
+
+void KnotHolderEntityAttachEnd::knot_set(Geom::Point const &p, Geom::Point const& /*origin*/, guint state)
+{
+    using namespace Geom;
+
+    LPETaperStroke* lpe = dynamic_cast<LPETaperStroke *>(_effect);
+
+    Geom::Point const s = snap_knot_position(p, state);
+
+    if (!SP_IS_SHAPE(lpe->sp_lpe_item) ) {
+        printf("WARNING: LPEItem is not a path!\n");
+        return;
+    }
+    
+    if (!SP_SHAPE(lpe->sp_lpe_item)->curve()) {
+        // oops
+        return;
+    }
+    Geom::PathVector pathv = lpe->pathvector_before_effect;
+    Geom::Path p_in = return_at_first_cusp(pathv[0].reversed());
+    Piecewise<D2<SBasis> > pwd2 = p_in.toPwSb();
+    
+    double t0 = nearest_time(s, pwd2);
+    lpe->attach_end.param_set_value(t0);
+
+    sp_lpe_item_update_patheffect (SP_LPE_ITEM(item), false, true);
+}
+
+Geom::Point KnotHolderEntityAttachBegin::knot_get() const
+{
+    LPETaperStroke const * lpe = dynamic_cast<LPETaperStroke const*> (_effect);
+    return lpe->start_attach_point;
+}
+
+Geom::Point KnotHolderEntityAttachEnd::knot_get() const
+{
+    LPETaperStroke const * lpe = dynamic_cast<LPETaperStroke const*> (_effect);
+    return lpe->end_attach_point;
+}
+
+} // namespace TpS
+} // 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 :