/** * \file line-snapper.cpp * \brief LineSnapper class. * * Authors: * Diederik van Lierop <mail@diedenrezi.nl> * And others... * * Copyright (C) 1999-2007 Authors * * Released under GNU GPL, read the file 'COPYING' for more information */ #include "libnr/nr-values.h" #include "libnr/nr-point-fns.h" #include <2geom/geom.h> #include "line-snapper.h" #include "snapped-line.h" #include <gtk/gtk.h> Inkscape::LineSnapper::LineSnapper(SPNamedView const *nv, NR::Coord const d) : Snapper(nv, d) { } void Inkscape::LineSnapper::_doFreeSnap(SnappedConstraints &sc, Inkscape::Snapper::PointType const &t, NR::Point const &p, bool const &f, std::vector<NR::Point> &points_to_snap, std::list<SPItem const *> const &it) const { /* Get the lines that we will try to snap to */ const LineList lines = _getSnapLines(p); // std::cout << "snap point " << p << " to: " << std::endl; for (LineList::const_iterator i = lines.begin(); i != lines.end(); i++) { NR::Point const p1 = i->second; // point at guide/grid line NR::Point const p2 = p1 + NR::rot90(i->first); // 2nd point at guide/grid line // std::cout << " line through " << i->second << " with normal " << i->first; g_assert(i->first != NR::Point(0,0)); // we cannot project on an linesegment of zero length NR::Point const p_proj = project_on_linesegment(p, p1, p2); NR::Coord const dist = NR::L2(p_proj - p); //Store any line that's within snapping range if (dist < getSnapperTolerance()) { _addSnappedLine(sc, p_proj, dist, i->first, i->second); // std::cout << " -> distance = " << dist; } // std::cout << std::endl; } } void Inkscape::LineSnapper::_doConstrainedSnap(SnappedConstraints &sc, Inkscape::Snapper::PointType const &/*t*/, NR::Point const &p, bool const &/*f*/, std::vector<NR::Point> &/*points_to_snap*/, ConstraintLine const &c, std::list<SPItem const *> const &/*it*/) const { /* Get the lines that we will try to snap to */ const LineList lines = _getSnapLines(p); for (LineList::const_iterator i = lines.begin(); i != lines.end(); i++) { if (NR::L2(c.getDirection()) > 0) { // Can't do a constrained snap without a constraint /* Normal to the line we're trying to snap along */ NR::Point const n(NR::rot90(NR::unit_vector(c.getDirection()))); NR::Point const point_on_line = c.hasPoint() ? c.getPoint() : p; /* Constant term of the line we're trying to snap along */ NR::Coord const q0 = dot(n, point_on_line); /* Constant term of the grid or guide line */ NR::Coord const q1 = dot(i->first, i->second); /* Try to intersect this line with the target line */ Geom::Point t_2geom(NR_HUGE, NR_HUGE); Geom::IntersectorKind const k = Geom::line_intersection(n.to_2geom(), q0, i->first.to_2geom(), q1, t_2geom); NR::Point t(t_2geom); if (k == Geom::intersects) { const NR::Coord dist = L2(t - p); if (dist < getSnapperTolerance()) { // When doing a constrained snap, we're already at an intersection. // This snappoint is therefore fully constrained, so there's no need // to look for additional intersections; just return the snapped point // and forget about the line sc.points.push_back(SnappedPoint(t, dist, getSnapperTolerance(), getSnapperAlwaysSnap())); } } } } } /* 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 :