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Diffstat (limited to 'src/snapped-curve.cpp')
| -rw-r--r-- | src/snapped-curve.cpp | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/src/snapped-curve.cpp b/src/snapped-curve.cpp new file mode 100644 index 0000000..70ad72e --- /dev/null +++ b/src/snapped-curve.cpp @@ -0,0 +1,260 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/** + * \file src/snapped-curve.cpp + * SnappedCurve class. + * + * Authors: + * Diederik van Lierop <mail@diedenrezi.nl> + * + * Released under GNU GPL v2+, read the file 'COPYING' for more information. + */ + +#include "snapped-curve.h" +#include <2geom/path-intersection.h> + +Inkscape::SnappedCurve::SnappedCurve(Geom::Point const &snapped_point, Geom::Point const &tangent, int num_path, int num_segm, Geom::Coord const &snapped_distance, Geom::Coord const &snapped_tolerance, bool const &always_snap, bool const &fully_constrained, Geom::Curve const *curve, SnapSourceType source, long source_num, SnapTargetType target, Geom::OptRect target_bbox) +{ + _num_path = num_path; + _num_segm = num_segm; + _distance = snapped_distance; + _tolerance = std::max(snapped_tolerance, 1.0); + _always_snap = always_snap; + _curve = curve; + _second_distance = Geom::infinity(); + _second_tolerance = 1; + _second_always_snap = false; + _point = snapped_point; + _tangent = tangent; + _at_intersection = false; + _fully_constrained = fully_constrained; + _source = source; + _source_num = source_num; + _target = target; + _target_bbox = target_bbox; +} + +Inkscape::SnappedCurve::SnappedCurve() +{ + _num_path = 0; + _num_segm = 0; + _distance = Geom::infinity(); + _tolerance = 1; + _always_snap = false; + _curve = nullptr; + _second_distance = Geom::infinity(); + _second_tolerance = 1; + _second_always_snap = false; + _point = Geom::Point(0,0); + _tangent = Geom::Point(0,0); + _at_intersection = false; + _fully_constrained = false; + _source = SNAPSOURCE_UNDEFINED; + _source_num = -1; + _target = SNAPTARGET_UNDEFINED; + _target_bbox = Geom::OptRect(); +} + +Inkscape::SnappedCurve::~SnappedCurve() += default; + +Inkscape::SnappedPoint Inkscape::SnappedCurve::intersect(SnappedCurve const &curve, Geom::Point const &p, Geom::Affine dt2doc) const +{ + // Calculate the intersections of two curves, which are both within snapping range, and + // return only the closest intersection + // The point of intersection should be considered for snapping, but might be outside the snapping range + // PS: We need p (the location of the mouse pointer) to find out which intersection is the + // closest, as there might be multiple intersections of two curves + Geom::Crossings cs = crossings(*(this->_curve), *(curve._curve)); + + if (cs.size() > 0) { + // There might be multiple intersections: find the closest + Geom::Coord best_dist = Geom::infinity(); + Geom::Point best_p = Geom::Point(Geom::infinity(), Geom::infinity()); + for (const auto & c : cs) { + Geom::Point p_ix = this->_curve->pointAt(c.ta); + Geom::Coord dist = Geom::distance(p_ix, p); + + // Test if we have two segments (curves) from the same path.. + if (this->_num_path == curve._num_path) { + // Never try to intersect a segment with itself + if (this->_num_segm == curve._num_segm) continue; + // Two subsequent segments (curves) in a path will have a common node; this node is not considered to be an intersection + if (this->_num_segm == curve._num_segm + 1 && c.ta == 0 && c.tb == 1) continue; + if (this->_num_segm + 1 == curve._num_segm && c.ta == 1 && c.tb == 0) continue; + } + + if (dist < best_dist) { + best_dist = dist; + best_p = p_ix; + } + } + + // Now we've found the closest intersection, return it as a SnappedPoint + bool const use_this_as_primary = _distance < curve.getSnapDistance(); + Inkscape::SnappedCurve const *primaryC = use_this_as_primary ? this : &curve; + Inkscape::SnappedCurve const *secondaryC = use_this_as_primary ? &curve : this; + + // The intersection should in fact be returned in desktop coordinates + best_p = best_p * dt2doc; + + Geom::Coord primaryDist = use_this_as_primary ? Geom::L2(best_p - this->getPoint()) : Geom::L2(best_p - curve.getPoint()); + Geom::Coord secondaryDist = use_this_as_primary ? Geom::L2(best_p - curve.getPoint()) : Geom::L2(best_p - this->getPoint()); + // TODO: Investigate whether it is possible to use document coordinates everywhere + // in the snapper code. Only the mouse position should be in desktop coordinates, I guess. + // All paths are already in document coords and we are certainly not going to change THAT. + return SnappedPoint(best_p, Inkscape::SNAPSOURCE_UNDEFINED, primaryC->getSourceNum(), Inkscape::SNAPTARGET_PATH_INTERSECTION, primaryDist, primaryC->getTolerance(), primaryC->getAlwaysSnap(), true, false, true, + secondaryDist, secondaryC->getTolerance(), secondaryC->getAlwaysSnap()); + } + + // No intersection + return SnappedPoint(Geom::Point(Geom::infinity(), Geom::infinity()), SNAPSOURCE_UNDEFINED, 0, SNAPTARGET_UNDEFINED, Geom::infinity(), 0, false, false, false, false, Geom::infinity(), 0, false); +} + +Inkscape::SnappedPoint Inkscape::SnappedCurve::intersect(SnappedLine const &line, Geom::Point const &p, Geom::Affine dt2doc) const +{ + // Calculate the intersections of a curve with a line, which are both within snapping range, and + // return only the closest intersection + // The point of intersection should be considered for snapping, but might be outside the snapping range + // PS: We need p (the location of the mouse pointer) to find out which intersection is the + // closest, as there might be multiple intersections of a single curve with a line + + // 1) get a Geom::Line object from the SnappedLine + // 2) convert to document coordinates (line and p are in desktop coordinates, but the curves are in document coordinate) + // 3) create a Geom::LineSegment (i.e. a curve), because we cannot use a Geom::Line for calculating intersections + // (for this we will create a 2e6 pixels long linesegment, with t running from -1e6 to 1e6; this should be long + // enough for any practical purpose) + Geom::LineSegment line_segm = line.getLine().transformed(dt2doc).segment(-1e6, 1e6); // + const Geom::Curve *line_as_curve = dynamic_cast<Geom::Curve const*>(&line_segm); + Geom::Crossings cs = crossings(*(this->_curve), *line_as_curve); + + if (cs.size() > 0) { + // There might be multiple intersections: find the closest + Geom::Coord best_dist = Geom::infinity(); + Geom::Point best_p = Geom::Point(Geom::infinity(), Geom::infinity()); + for (const auto & c : cs) { + Geom::Point p_ix = this->_curve->pointAt(c.ta); + Geom::Coord dist = Geom::distance(p_ix, p); + + if (dist < best_dist) { + best_dist = dist; + best_p = p_ix; + } + } + + // The intersection should in fact be returned in desktop coordinates + best_p = best_p * dt2doc; + + // Now we've found the closest intersection, return it as a SnappedPoint + if (_distance < line.getSnapDistance()) { + // curve is the closest, so this is our primary snap target + return SnappedPoint(best_p, Inkscape::SNAPSOURCE_UNDEFINED, this->getSourceNum(), Inkscape::SNAPTARGET_PATH_GUIDE_INTERSECTION, + Geom::L2(best_p - this->getPoint()), this->getTolerance(), this->getAlwaysSnap(), true, false, true, + Geom::L2(best_p - line.getPoint()), line.getTolerance(), line.getAlwaysSnap()); + } else { + return SnappedPoint(best_p, Inkscape::SNAPSOURCE_UNDEFINED, line.getSourceNum(), Inkscape::SNAPTARGET_PATH_GUIDE_INTERSECTION, + Geom::L2(best_p - line.getPoint()), line.getTolerance(), line.getAlwaysSnap(), true, false, true, + Geom::L2(best_p - this->getPoint()), this->getTolerance(), this->getAlwaysSnap()); + } + } + + // No intersection + return SnappedPoint(Geom::Point(Geom::infinity(), Geom::infinity()), SNAPSOURCE_UNDEFINED, 0, SNAPTARGET_UNDEFINED, Geom::infinity(), 0, false, false, false, false, Geom::infinity(), 0, false); +} + + +// search for the closest snapped line +bool getClosestCurve(std::list<Inkscape::SnappedCurve> const &list, Inkscape::SnappedCurve &result, bool exclude_paths) +{ + bool success = false; + + for (std::list<Inkscape::SnappedCurve>::const_iterator i = list.begin(); i != list.end(); ++i) { + if (exclude_paths && ((*i).getTarget() == Inkscape::SNAPTARGET_PATH)) { + continue; + } + if ((i == list.begin()) || (*i).getSnapDistance() < result.getSnapDistance()) { + result = *i; + success = true; + } + } + + return success; +} + +// search for the closest intersection of two snapped curves, which are both member of the same collection +bool getClosestIntersectionCS(std::list<Inkscape::SnappedCurve> const &list, Geom::Point const &p, Inkscape::SnappedPoint &result, Geom::Affine dt2doc) +{ + bool success = false; + + for (std::list<Inkscape::SnappedCurve>::const_iterator i = list.begin(); i != list.end(); ++i) { + if ((*i).getTarget() != Inkscape::SNAPTARGET_BBOX_EDGE) { // We don't support snapping to intersections of bboxes, + // as this would require two bboxes two be flashed in the snap indicator + std::list<Inkscape::SnappedCurve>::const_iterator j = i; + ++j; + for (; j != list.end(); ++j) { + if ((*j).getTarget() != Inkscape::SNAPTARGET_BBOX_EDGE) { // We don't support snapping to intersections of bboxes + Inkscape::SnappedPoint sp = (*i).intersect(*j, p, dt2doc); + if (sp.getAtIntersection()) { + // if it's the first point + bool const c1 = !success; + // or, if it's closer + bool const c2 = sp.getSnapDistance() < result.getSnapDistance(); + // or, if it's just as close then look at the other distance + // (only relevant for snapped points which are at an intersection) + bool const c3 = (sp.getSnapDistance() == result.getSnapDistance()) && (sp.getSecondSnapDistance() < result.getSecondSnapDistance()); + // then prefer this point over the previous one + if (c1 || c2 || c3) { + result = sp; + success = true; + } + } + } + } + } + } + + return success; +} + +// search for the closest intersection of two snapped curves, which are member of two different collections +bool getClosestIntersectionCL(std::list<Inkscape::SnappedCurve> const &curve_list, std::list<Inkscape::SnappedLine> const &line_list, Geom::Point const &p, Inkscape::SnappedPoint &result, Geom::Affine dt2doc) +{ + bool success = false; + + for (const auto & i : curve_list) { + if (i.getTarget() != Inkscape::SNAPTARGET_BBOX_EDGE) { // We don't support snapping to intersections of bboxes, + // as this would require two bboxes two be flashed in the snap indicator + for (const auto & j : line_list) { + if (j.getTarget() != Inkscape::SNAPTARGET_BBOX_EDGE) { // We don't support snapping to intersections of bboxes + Inkscape::SnappedPoint sp = i.intersect(j, p, dt2doc); + if (sp.getAtIntersection()) { + // if it's the first point + bool const c1 = !success; + // or, if it's closer + bool const c2 = sp.getSnapDistance() < result.getSnapDistance(); + // or, if it's just as close then look at the other distance + // (only relevant for snapped points which are at an intersection) + bool const c3 = (sp.getSnapDistance() == result.getSnapDistance()) && (sp.getSecondSnapDistance() < result.getSecondSnapDistance()); + // then prefer this point over the previous one + if (c1 || c2 || c3) { + result = sp; + success = true; + } + } + } + } + } + } + + return success; +} + +/* + 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 : |