diff options
Diffstat (limited to '')
| -rw-r--r-- | src/line-snapper.cpp | 61 |
1 files changed, 39 insertions, 22 deletions
diff --git a/src/line-snapper.cpp b/src/line-snapper.cpp index fc40643c8..5ceece66b 100644 --- a/src/line-snapper.cpp +++ b/src/line-snapper.cpp @@ -63,7 +63,7 @@ void Inkscape::LineSnapper::freeSnap(SnappedConstraints &sc, void Inkscape::LineSnapper::constrainedSnap(SnappedConstraints &sc, Inkscape::SnapCandidatePoint const &p, Geom::OptRect const &/*bbox_to_snap*/, - ConstraintLine const &c, + SnapConstraint const &c, std::vector<SPItem const *> const */*it*/) const { @@ -75,20 +75,46 @@ void Inkscape::LineSnapper::constrainedSnap(SnappedConstraints &sc, const LineList lines = _getSnapLines(p.getPoint()); for (LineList::const_iterator i = lines.begin(); i != lines.end(); i++) { - if (Geom::L2(c.getDirection()) > 0) { // Can't do a constrained snap without a constraint - // constraint line - Geom::Point const point_on_line = c.hasPoint() ? c.getPoint() : p.getPoint(); - Geom::Line line1(point_on_line, point_on_line + c.getDirection()); - - // grid/guide line - Geom::Point const p1 = i->second; // point at guide/grid line - Geom::Point const p2 = p1 + Geom::rot90(i->first); // 2nd point at guide/grid line - Geom::Line line2(p1, p2); + Geom::Point const point_on_line = c.hasPoint() ? c.getPoint() : p.getPoint(); + Geom::Line gridguide_line(i->second, i->second + Geom::rot90(i->first)); + if (c.isCircular()) { + // Find the intersections between the line and the circular constraint + // First, project the origin of the circle onto the line + Geom::Point const origin = c.getPoint(); + Geom::Point const p_proj = Geom::projection(origin, gridguide_line); + Geom::Point v_orig = c.getDirection(); // vector from the origin to the original (untransformed) point + Geom::Point v_proj = p_proj - origin; + Geom::Coord dist = Geom::L2(v_proj); // distance from circle origin to constraint line + Geom::Coord radius = c.getRadius(); + Geom::Coord radians = NR_HUGE; + if (dist == radius) { + // Only one point of intersection; + // Calculate the rotation in radians... + radians = atan2(Geom::dot(Geom::rot90(v_orig), v_proj), Geom::dot(v_orig, v_proj)); + _addSnappedPoint(sc, p_proj, Geom::L2(p.getPoint() - p_proj), p.getSourceType(), p.getSourceNum(), true, radians); + } else if (dist < radius) { + // Two points of intersection, symmetrical with respect to the projected point + // Calculate half the length of the linesegment between the two points of intersection + Geom::Coord l = sqrt(radius*radius - dist*dist); + Geom::Coord d = Geom::L2(gridguide_line.versor()); // length of versor, needed to normalize the versor + if (d > 0) { + Geom::Point v = l*gridguide_line.versor()/d; + v_proj = p_proj + v - origin; + radians = atan2(Geom::dot(Geom::rot90(v_orig), v_proj), Geom::dot(v_orig, v_proj)); + _addSnappedPoint(sc, p_proj + v, Geom::L2(p.getPoint() - (p_proj + v)), p.getSourceType(), p.getSourceNum(), true, radians); + v_proj = p_proj - v - origin; + radians = atan2(Geom::dot(Geom::rot90(v_orig), v_proj), Geom::dot(v_orig, v_proj)); + _addSnappedPoint(sc, p_proj - v, Geom::L2(p.getPoint() - (p_proj - v)), p.getSourceType(), p.getSourceNum(), true, radians); + } + } + } else { + // Find the intersections between the line and the linear constraint + Geom::Line constraint_line(point_on_line, point_on_line + c.getDirection()); Geom::OptCrossing inters = Geom::OptCrossing(); // empty by default try { - inters = Geom::intersection(line1, line2); + inters = Geom::intersection(constraint_line, gridguide_line); } catch (Geom::InfiniteSolutions e) { @@ -97,23 +123,14 @@ void Inkscape::LineSnapper::constrainedSnap(SnappedConstraints &sc, } if (inters) { - Geom::Point t = line1.pointAt((*inters).ta); + Geom::Point t = constraint_line.pointAt((*inters).ta); const Geom::Coord dist = Geom::L2(t - p.getPoint()); 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 - _addSnappedPoint(sc, t, dist, p.getSourceType(), p.getSourceNum(), true); - // For any line that's within range, we will also look at it's "point on line" p1. For guides - // this point coincides with its origin; for grids this is of no use, but we cannot - // discern between grids and guides here - Geom::Coord const dist_p1 = Geom::L2(p1 - p.getPoint()); - if (dist_p1 < getSnapperTolerance()) { - _addSnappedLinesOrigin(sc, p1, dist_p1, p.getSourceType(), p.getSourceNum(), true); - // Only relevant for guides; grids don't have an origin per line - // Therefore _addSnappedLinesOrigin() will only be implemented for guides - } + _addSnappedPoint(sc, t, dist, p.getSourceType(), p.getSourceNum(), true, 1); } } } |