diff --git a/src/snap.cpp b/src/snap.cpp
index bac37737fc5589187da7b12b5fdf19425968a739..bcacb81e2328416447589344e395ee48408b52d5 100644 (file)
--- a/src/snap.cpp
+++ b/src/snap.cpp
@@ -389,6 +389,68 @@ Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::SnapCandidatePoint
return no_snap;
}
+/* See the documentation for constrainedSnap() directly above for more details.
+ * The difference is that multipleConstrainedSnaps() will take a list of constraints instead of a single one,
+ * and will try to snap the SnapCandidatePoint to all of the provided constraints and see which one fits best
+ * \param p Source point to be snapped
+ * \param constraints List of directions or lines along which snapping must occur
+ * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
+ */
+
+
+Inkscape::SnappedPoint SnapManager::multipleConstrainedSnaps(Inkscape::SnapCandidatePoint const &p,
+ std::vector<Inkscape::Snapper::SnapConstraint> const &constraints,
+ Geom::OptRect const &bbox_to_snap) const
+{
+
+ Inkscape::SnappedPoint no_snap = Inkscape::SnappedPoint(p.getPoint(), p.getSourceType(), p.getSourceNum(), Inkscape::SNAPTARGET_CONSTRAINT, NR_HUGE, 0, false, true, false);
+ if (constraints.size() == 0) {
+ return no_snap;
+ }
+
+ SnappedConstraints sc;
+ SnapperList const snappers = getSnappers();
+ std::vector<Geom::Point> projections;
+ bool snapping_is_futile = !someSnapperMightSnap();
+
+ // Iterate over the constraints
+ for (std::vector<Inkscape::Snapper::SnapConstraint>::const_iterator c = constraints.begin(); c != constraints.end(); c++) {
+ // Project the mouse pointer onto the constraint; In case we don't snap then we will
+ // return the projection onto the constraint, such that the constraint is always enforced
+ Geom::Point pp = (*c).projection(p.getPoint());
+ projections.push_back(pp);
+ // Try to snap to the constraint
+ if (!snapping_is_futile) {
+ for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
+ (*i)->constrainedSnap(sc, p, bbox_to_snap, *c, &_items_to_ignore);
+ }
+ }
+ }
+
+ Inkscape::SnappedPoint result = findBestSnap(p, sc, true);
+
+ if (result.getSnapped()) {
+ // only change the snap indicator if we really snapped to something
+ if (_snapindicator) {
+ _desktop->snapindicator->set_new_snaptarget(result);
+ }
+ return result;
+ }
+
+ // So we didn't snap, but we still need to return a point on one of the constraints
+ // Find out which of the constraints yielded the closest projection of point p
+ no_snap.setPoint(projections.front());
+ for (std::vector<Geom::Point>::iterator pp = projections.begin(); pp != projections.end(); pp++) {
+ if (pp != projections.begin()) {
+ if (Geom::L2(*pp - p.getPoint()) < Geom::L2(no_snap.getPoint() - p.getPoint())) {
+ no_snap.setPoint(*pp);
+ }
+ }
+ }
+
+ return no_snap;
+}
+
/**
* \brief Try to snap a point of a guide to another guide or to a node
*
// calculate that line here
dedicated_constraint = Inkscape::Snapper::SnapConstraint(origin, b);
} else if (transformation_type == ROTATE) {
- // Geom::L2(b) is the radius of the circular constraint
- dedicated_constraint = Inkscape::Snapper::SnapConstraint(origin, b, Geom::L2(b));
+ Geom::Coord r = Geom::L2(b); // the radius of the circular constraint
+ if (r < 1e-9) { // points too close to the rotation center will not move. Don't try to snap these
+ // as they will always yield a perfect snap result if they're already snapped beforehand (e.g.
+ // when the transformation center has been snapped to a grid intersection in the selector tool)
+ continue; // skip this SnapCandidate and continue with the next one
+ // PS1: Apparently we don't have to do this for skewing, but why?
+ // PS2: We cannot easily filter these points upstream, e.g. in the grab() method (seltrans.cpp)
+ // because the rotation center will change when pressing shift, and grab() won't be recalled.
+ // Filtering could be done in handleRequest() (again in seltrans.cpp), by iterating through
+ // the snap candidates. But hey, we're iterating here anyway.
+ }
+ dedicated_constraint = Inkscape::Snapper::SnapConstraint(origin, b, r);
} else if (transformation_type == STRETCH) { // when non-uniform stretching {
dedicated_constraint = Inkscape::Snapper::SnapConstraint((*i).getPoint(), component_vectors[dim]);
} else if (transformation_type == TRANSLATE) {
snapped_point.setSecondSnapDistance(NR_HUGE);
break;
case ROTATE:
- // a is vector to snapped point; b is vector to original point; now lets calculate angle between a and b
- result[0] = atan2(Geom::dot(Geom::rot90(b), a), Geom::dot(b, a));
- result[1] = result[1]; // how else should we store an angle in a point ;-)
+ // a is vector to snapped point; b is vector to original point; now lets calculate angle between a and b
+ result[0] = atan2(Geom::dot(Geom::rot90(b), a), Geom::dot(b, a));
+ result[1] = result[1]; // how else should we store an angle in a point ;-)
// Store the metric for this transformation as a virtual distance (we're storing an angle)
snapped_point.setSnapDistance(std::abs(result[0] - transformation[0]));
snapped_point.setSecondSnapDistance(NR_HUGE);