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diff --git a/src/line-snapper.cpp b/src/line-snapper.cpp
index 446ec73e73deab0c57eafa6545f2b9533597f350..a84a802961fe04ed40a6bd9411bcb9e51bb637d5 100644 (file)
--- a/src/line-snapper.cpp
+++ b/src/line-snapper.cpp
#include "libnr/nr-point-fns.h"
#include <2geom/geom.h>
#include "line-snapper.h"
-#include "snapped-line.cpp"
+#include "snapped-line.h"
#include <gtk/gtk.h>
Inkscape::LineSnapper::LineSnapper(SPNamedView const *nv, NR::Coord const d) : Snapper(nv, d)
std::vector<NR::Point> &points_to_snap,
std::list<SPItem const *> const &it) const
{
- Inkscape::SnappedPoint s = SnappedPoint(p, NR_HUGE);
-
/* 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++) {
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
- g_assert(i->first != NR::Point(0,0)); // otherwise we'll have div. by zero because NR::L2(d2) = 0
-
- // p_proj = projection of p on the grid/guide line running from p1 to p2
- // p_proj = p1 + u (p2 - p1)
- // calculate u according to "Minimum Distance between a Point and a Line"
- // see http://local.wasp.uwa.edu.au/~pbourke/geometry/pointline/
- NR::Point const d1(p-p1); // delta 1
- NR::Point const d2(p2-p1); // delta 1
- double const u = (d1[NR::X] * d2[NR::X] + d1[NR::Y] * d2[NR::Y]) / (NR::L2(d2) * NR::L2(d2));
-
- NR::Point const p_proj(p1 + u*(p2-p1));
+ 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 < getDistance()) {
+ if (dist < getSnapperTolerance()) {
_addSnappedLine(sc, p_proj, dist, i->first, i->second);
// std::cout << " -> distance = " << dist;
}
std::list<SPItem const *> const &/*it*/) const
{
- Inkscape::SnappedPoint s = SnappedPoint(p, NR_HUGE);
-
/* 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++) {
-
- /* 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);
- //Store any line that's within snapping range
- if (dist < getDistance()) {
- _addSnappedLine(sc, t, dist, c.getDirection(), t);
+ 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()));
+ }
}
}
}