1 files changed, 624 insertions, 0 deletions
diff --git a/src/display/curve.cpp b/src/display/curve.cpp
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--- /dev/null
+++ b/src/display/curve.cpp
@@ -0,0 +1,624 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/**
+ * Authors:
+ *   Lauris Kaplinski <lauris@kaplinski.com>
+ *   Johan Engelen
+ *
+ * Copyright (C) 2000 Lauris Kaplinski
+ * Copyright (C) 2000-2001 Ximian, Inc.
+ * Copyright (C) 2002 Lauris Kaplinski
+ * Copyright (C) 2008 Johan Engelen
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include "display/curve.h"
+
+#include <glib.h> // g_error
+#include <2geom/sbasis-geometric.h>
+#include <2geom/sbasis-to-bezier.h>
+#include <2geom/point.h>
+#include "helper/geom.h"
+#include "helper/geom-pathstroke.h"
+
+/**
+ * Routines for SPCurve and for its Geom::PathVector
+ */
+
+SPCurve::SPCurve(Geom::Rect const &rect, bool all_four_sides)
+{
+    moveto(rect.corner(0));
+
+    for (int i = 3; i >= 1; --i) {
+        lineto(rect.corner(i));
+    }
+
+    if (all_four_sides) {
+        // When _constrained_ snapping to a path, the 2geom::SimpleCrosser will be invoked which doesn't consider the closing segment.
+        // of a path. Consequently, in case we want to snap to for example the page border, we must provide all four sides of the
+        // rectangle explicitly
+        lineto(rect.corner(0));
+    } else {
+        // ... instead of just three plus a closing segment
+        closepath();
+    }
+}
+
+void SPCurve::set_pathvector(Geom::PathVector const &new_pathv)
+{
+    _pathv = new_pathv;
+}
+
+Geom::PathVector const &SPCurve::get_pathvector() const
+{
+    return _pathv;
+}
+
+/**
+ * Returns the number of segments of all paths summed.
+ * This count includes the closing line segment of a closed path.
+ */
+size_t SPCurve::get_segment_count() const
+{
+    return _pathv.curveCount();
+}
+
+/**
+ * Returns a list of curves corresponding to the subpaths in \a curve.
+ */
+std::vector<SPCurve> SPCurve::split() const
+{
+    std::vector<SPCurve> result;
+
+    for (auto const &path_it : _pathv) {
+        Geom::PathVector newpathv;
+        newpathv.push_back(path_it);
+        result.emplace_back(std::move(newpathv));
+    }
+
+    return result;
+}
+
+/**
+ * Returns a list of curves of non-overlapping subpath in \a curve.
+ */
+std::vector<SPCurve> SPCurve::split_non_overlapping() const
+{
+    std::vector<SPCurve> result;
+
+    auto curves = Inkscape::split_non_intersecting_paths(Geom::PathVector(_pathv));
+
+    for (auto &curve : curves) {
+        result.emplace_back(std::move(curve));
+    }
+
+    return result;
+}
+
+/**
+ * Transform all paths in curve by matrix.
+ */
+void SPCurve::transform(Geom::Affine const &m)
+{
+    _pathv *= m;
+}
+
+/**
+ * Return a copy of the curve with all paths transformed by matrix.
+ */
+SPCurve SPCurve::transformed(const Geom::Affine &m) const
+{
+    return SPCurve(_pathv * m);
+}
+
+/**
+ * Set curve to empty curve.
+ * In more detail: this clears the internal pathvector from all its paths.
+ */
+void SPCurve::reset()
+{
+    _pathv.clear();
+}
+
+/** Several consecutive movetos are ALLOWED
+ *  Ref: http://www.w3.org/TR/SVG11/implnote.html#PathElementImplementationNotes
+ * (first subitem of the item about zero-length path segments) */
+/**
+ * Calls SPCurve::moveto() with point made of given coordinates.
+ */
+void SPCurve::moveto(double x, double y)
+{
+    moveto(Geom::Point(x, y));
+}
+
+/**
+ * Perform a moveto to a point, thus starting a new subpath.
+ * Point p must be finite.
+ */
+void SPCurve::moveto(Geom::Point const &p)
+{
+    Geom::Path path(p);
+    path.setStitching(true);
+    _pathv.push_back(path);
+}
+
+/**
+ * Adds a line to the current subpath.
+ * Point p must be finite.
+ */
+void SPCurve::lineto(Geom::Point const &p)
+{
+    if (_pathv.empty()) {
+        g_message("SPCurve::lineto - path is empty!");
+    } else {
+        _pathv.back().appendNew<Geom::LineSegment>(p);
+    }
+}
+/**
+ * Calls SPCurve::lineto( Geom::Point(x,y) )
+ */
+void SPCurve::lineto(double x, double y)
+{
+    lineto(Geom::Point(x, y));
+}
+
+/**
+ * Adds a quadratic bezier segment to the current subpath.
+ * All points must be finite.
+ */
+void SPCurve::quadto(Geom::Point const &p1, Geom::Point const &p2)
+{
+    if (_pathv.empty()) {
+        g_message("SPCurve::quadto - path is empty!");
+    } else {
+        _pathv.back().appendNew<Geom::QuadraticBezier>(p1, p2);
+    }
+}
+/**
+ * Calls SPCurve::quadto( Geom::Point(x1,y1), Geom::Point(x2,y2) )
+ * All coordinates must be finite.
+ */
+void SPCurve::quadto(double x1, double y1, double x2, double y2)
+{
+    quadto(Geom::Point(x1, y1), Geom::Point(x2, y2));
+}
+
+/**
+ * Adds a bezier segment to the current subpath.
+ * All points must be finite.
+ */
+void SPCurve::curveto(Geom::Point const &p0, Geom::Point const &p1, Geom::Point const &p2)
+{
+    if (_pathv.empty()) {
+        g_message("SPCurve::curveto - path is empty!");
+    } else {
+        _pathv.back().appendNew<Geom::CubicBezier>(p0, p1, p2);
+    }
+}
+/**
+ * Calls SPCurve::curveto( Geom::Point(x0,y0), Geom::Point(x1,y1), Geom::Point(x2,y2) )
+ * All coordinates must be finite.
+ */
+void SPCurve::curveto(double x0, double y0, double x1, double y1, double x2, double y2)
+{
+    curveto(Geom::Point(x0, y0), Geom::Point(x1, y1), Geom::Point(x2, y2));
+}
+
+/**
+ * Close current subpath by possibly adding a line between start and end.
+ */
+void SPCurve::closepath()
+{
+    if (_pathv.empty()) {
+        g_message("%s - path is empty", __PRETTY_FUNCTION__);
+    } else {
+        _pathv.back().close(true);
+    }
+}
+
+/** Like SPCurve::closepath() but sets the end point of the last subpath
+ *  to the subpath start point instead of adding a new lineto.
+ *
+ *  Used for freehand drawing when the user draws back to the start point.
+ */
+void SPCurve::closepath_current()
+{
+    if (_pathv.back().size() > 0 && dynamic_cast<Geom::LineSegment const *>(&_pathv.back().back_open())) {
+        _pathv.back().erase_last();
+    } else {
+        _pathv.back().setFinal(_pathv.back().initialPoint());
+    }
+    _pathv.back().close(true);
+}
+
+/**
+ * True if no paths are in curve. If it only contains a path with only a moveto, the path is considered NON-empty
+ */
+bool SPCurve::is_empty() const
+{
+    return _pathv.empty();
+}
+
+/**
+ * True if paths are in curve. If it only contains a path with only a moveto, the path is considered as unset FALSE
+ */
+bool SPCurve::is_unset() const
+{
+    return get_segment_count() == 0;
+}
+
+/**
+ * True iff all subpaths are closed.
+ * Returns false if the curve is empty.
+ */
+bool SPCurve::is_closed() const
+{
+    if (is_empty()) {
+        return false;
+    } 
+    
+    for (auto const &it : _pathv) {
+        if (!it.closed()) {
+            return false;
+        }
+    }
+    
+    return true;    
+}
+
+/**
+ * True if both curves are equal
+ */
+bool SPCurve::is_equal(SPCurve const *other) const
+{
+    return other && _pathv == other->get_pathvector();
+}
+
+/**
+ * True if both curves are near
+ */
+bool SPCurve::is_similar(SPCurve const *other, double precision) const
+{
+    return other && pathv_similar(_pathv, other->get_pathvector(), precision);
+}
+
+/**
+ * Return last pathsegment (possibly the closing path segment) of the last path in PathVector or NULL.
+ * If the last path is empty (contains only a moveto), the function returns NULL
+ */
+Geom::Curve const *SPCurve::last_segment() const
+{
+    if (is_empty()) {
+        return nullptr;
+    }
+    if (_pathv.back().empty()) {
+        return nullptr;
+    }
+
+    return &_pathv.back().back_default();
+}
+
+/**
+ * Return last path in PathVector or NULL.
+ */
+Geom::Path const *SPCurve::last_path() const
+{
+    if (is_empty()) {
+        return nullptr;
+    }
+
+    return &_pathv.back();
+}
+
+/**
+ * Return first pathsegment in PathVector or NULL.
+ * equal in functionality to SPCurve::first_bpath()
+ */
+Geom::Curve const *SPCurve::first_segment() const
+{
+    if (is_empty()) {
+        return nullptr;
+    }
+    if (_pathv.front().empty()) {
+        return nullptr;
+    }
+
+    return &_pathv.front().front();
+}
+
+/**
+ * Return first path in PathVector or NULL.
+ */
+Geom::Path const *SPCurve::first_path() const
+{
+    if (is_empty()) {
+        return nullptr;
+    }
+
+    return &_pathv.front();
+}
+
+/**
+ * Return first point of first subpath or nothing when the path is empty.
+ */
+std::optional<Geom::Point> SPCurve::first_point() const
+{
+    if (is_empty()) {
+        return {};
+    }
+
+    return _pathv.front().initialPoint();
+}
+
+/**
+ * Return the second point of first subpath or _movePos if curve too short.
+ * If the pathvector is empty, this returns nothing. If the first path is only a moveto, this method
+ * returns the first point of the second path, if it exists. If there is no 2nd path, it returns the
+ * first point of the first path.
+ */
+std::optional<Geom::Point> SPCurve::second_point() const
+{
+    if (is_empty()) {
+        return {};
+    }
+
+    if (_pathv.front().empty()) {
+        // first path is only a moveto
+        // check if there is second path
+        if (_pathv.size() > 1) {
+            return _pathv[1].initialPoint();
+        } else {
+            return _pathv[0].initialPoint();
+        }
+    }
+
+    return _pathv.front()[0].finalPoint();
+}
+
+/**
+ * Return the second-last point of last subpath or first point when that last subpath has only a moveto.
+ */
+std::optional<Geom::Point> SPCurve::penultimate_point() const
+{
+    if (is_empty()) {
+        return {};
+    }
+
+    Geom::Path const &lastpath = _pathv.back();
+    if (!lastpath.empty()) {
+        return lastpath.back_default().initialPoint();
+    } else {
+        return lastpath.initialPoint();
+    }
+}
+
+/**
+ * Return last point of last subpath or nothing when the curve is empty.
+ * If the last path is only a moveto, then return that point.
+ */
+std::optional<Geom::Point> SPCurve::last_point() const
+{
+    if (is_empty()) {
+        return {};
+    }
+
+    return _pathv.back().finalPoint();
+}
+
+/**
+ * Reverse the direction of all paths.
+ */
+void SPCurve::reverse()
+{
+    _pathv.reverse();
+}
+
+/**
+ * Return a copy with the direction of all paths reversed.
+ */
+SPCurve SPCurve::reversed() const
+{
+    return SPCurve(_pathv.reversed());
+}
+
+/**
+ * Append \a curve2 to \a this.
+ * If \a use_lineto is false, simply add all paths in \a curve2 to \a this;
+ * if \a use_lineto is true, combine \a this's last path and \a curve2's first path and add the rest of the paths in \a curve2 to \a this.
+ */
+void SPCurve::append(SPCurve const &curve2, bool use_lineto)
+{
+    append(curve2._pathv, use_lineto);
+}
+
+void SPCurve::append(Geom::PathVector const &pathv, bool use_lineto)
+{
+    if (pathv.empty()) {
+        return;
+    }
+
+    if (use_lineto) {
+        auto it = pathv.begin();
+        if (!_pathv.empty()) {
+            Geom::Path &lastpath = _pathv.back();
+            lastpath.appendNew<Geom::LineSegment>(it->initialPoint());
+            lastpath.append(*it);
+        } else {
+            _pathv.push_back(*it);
+        }
+
+        for (++it; it != pathv.end(); ++it) {
+            _pathv.push_back(*it);
+        }
+    } else {
+        for (auto const &it : pathv) {
+            _pathv.push_back(it);
+        }
+    }
+}
+
+/**
+ * Append \a c1 to \a this with possible fusing of close endpoints. If the end of this curve and the start of c1 are within tolerance distance,
+ * then the startpoint of c1 is moved to the end of this curve and the first subpath of c1 is appended to the last subpath of this curve.
+ * When one of the curves is empty, this curves path becomes the non-empty path.
+ *
+ * @param tolerance Tolerance for endpoint fusion (applied to x and y separately)
+ * @return False if one of the curves (this curve or the argument curve) is closed, true otherwise.
+ */
+bool SPCurve::append_continuous(SPCurve const &c1, double tolerance)
+{
+    if (is_closed() || c1.is_closed()) {
+        return false;
+    }
+
+    if (c1.is_empty()) {
+        return true;
+    }
+
+    if (this->is_empty()) {
+        _pathv = c1._pathv;
+        return true;
+    }
+
+    if ((fabs(last_point()->x() - c1.first_point()->x()) <= tolerance) &&
+        (fabs(last_point()->y() - c1.first_point()->y()) <= tolerance)) {
+    // c1's first subpath can be appended to this curve's last subpath
+        Geom::PathVector::const_iterator path_it = c1._pathv.begin();
+        Geom::Path & lastpath = _pathv.back();
+
+        Geom::Path newfirstpath(*path_it);
+        newfirstpath.setInitial(lastpath.finalPoint());
+        lastpath.append(newfirstpath);
+
+        for (++path_it; path_it != c1._pathv.end(); ++path_it) {
+            _pathv.push_back(*path_it);
+        }
+
+    } else {
+        append(c1, true);
+    }
+
+    return true;
+}
+
+/**
+ * Remove last segment of curve.
+ */
+void SPCurve::backspace()
+{
+    if (is_empty()) {
+        return;
+    }
+
+    if (!_pathv.back().empty()) {
+        _pathv.back().erase_last();
+        _pathv.back().close(false);
+    }
+}
+
+/**
+ * TODO: add comments about what this method does and what assumptions are made and requirements are put on SPCurve
+ (2:08:18 AM) Johan: basically, i convert the path to pw<d2>
+(2:08:27 AM) Johan: then i calculate an offset path
+(2:08:29 AM) Johan: to move the knots
+(2:08:36 AM) Johan: then i add it
+(2:08:40 AM) Johan: then convert back to path
+If I remember correctly, this moves the firstpoint to new_p0, and the lastpoint to new_p1, and moves all nodes in between according to their arclength (interpolates the movement amount)
+ */
+void SPCurve::stretch_endpoints(Geom::Point const &new_p0, Geom::Point const &new_p1)
+{
+    if (is_empty()) {
+        return;
+    }
+
+    auto const offset0 = new_p0 - *first_point();
+    auto const offset1 = new_p1 - *last_point();
+
+    Geom::Piecewise<Geom::D2<Geom::SBasis>> pwd2 = _pathv.front().toPwSb();
+    Geom::Piecewise<Geom::SBasis> arclength = Geom::arcLengthSb(pwd2);
+    if (arclength.lastValue() <= 0) {
+        g_error("SPCurve::stretch_endpoints - arclength <= 0");
+    }
+    arclength *= 1./arclength.lastValue();
+    auto const A = offset0;
+    auto const B = offset1;
+    Geom::Piecewise<Geom::SBasis> offsetx = (arclength*-1.+1)*A[0] + arclength*B[0];
+    Geom::Piecewise<Geom::SBasis> offsety = (arclength*-1.+1)*A[1] + arclength*B[1];
+    Geom::Piecewise<Geom::D2<Geom::SBasis>> offsetpath = Geom::sectionize(Geom::D2<Geom::Piecewise<Geom::SBasis>>(offsetx, offsety));
+    pwd2 += offsetpath;
+    _pathv = Geom::path_from_piecewise(pwd2, 0.001);
+}
+
+/**
+ *  sets start of first path to new_p0, and end of first path to  new_p1
+ */
+void SPCurve::move_endpoints(Geom::Point const &new_p0, Geom::Point const &new_p1)
+{
+    if (is_empty()) {
+        return;
+    }
+    _pathv.front().setInitial(new_p0);
+    _pathv.front().setFinal(new_p1);
+}
+
+/**
+ * returns the number of nodes in a path, used for statusbar text when selecting an spcurve.
+ * Sum of nodes in all the paths. When a path is closed, and its closing line segment is of zero-length,
+ * this function will not count the closing knot double (so basically ignores the closing line segment when it has zero length)
+ */
+size_t SPCurve::nodes_in_path() const
+{
+    size_t nr = 0;
+
+    for (auto const &it : _pathv) {
+        // if the path does not have any segments, it is a naked moveto,
+        // and therefore any path has at least one valid node
+        size_t psize = std::max<size_t>(1, it.size_closed());
+        nr += psize;
+        if (it.closed() && it.size_closed() > 0) {
+            Geom::Curve const &closingline = it.back_closed();
+            // the closing line segment is always of type
+            // Geom::LineSegment.
+            if (are_near(closingline.initialPoint(), closingline.finalPoint())) {
+                // closingline.isDegenerate() did not work, because it only checks for
+                // *exact* zero length, which goes wrong for relative coordinates and
+                // rounding errors...
+                // the closing line segment has zero-length. So stop before that one!
+                nr -= 1;
+            }
+        }
+    }
+
+    return nr;
+}
+
+/**
+ *  Adds p to the last point (and last handle if present) of the last path
+ */
+void SPCurve::last_point_additive_move(Geom::Point const &p)
+{
+    if (is_empty()) {
+        return;
+    }
+
+    _pathv.back().setFinal(_pathv.back().finalPoint() + p);
+
+    // Move handle as well when the last segment is a cubic bezier segment:
+    // TODO: what to do for quadratic beziers?
+    if (auto const lastcube = dynamic_cast<Geom::CubicBezier const *>(&_pathv.back().back())) {
+        Geom::CubicBezier newcube(*lastcube);
+        newcube.setPoint(2, newcube[2] + p);
+        _pathv.back().replace(--_pathv.back().end(), newcube);
+    }
+}
+
+/*
+  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: