From: Diederik van Lierop Date: Sat, 7 Aug 2010 08:15:18 +0000 (+0200) Subject: Add a constrained snap method that takes multiple constraints. This reduces the code... X-Git-Url: https://git.tokkee.org/?a=commitdiff_plain;h=e72129e933476ac0c1c78741d5d7490bd99ef49c;p=inkscape.git Add a constrained snap method that takes multiple constraints. This reduces the code repetitiveness in the node tool --- diff --git a/src/snap.cpp b/src/snap.cpp index 810e2dd8b..bcacb81e2 100644 --- 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 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 projections; + bool snapping_is_futile = !someSnapperMightSnap(); + + // Iterate over the constraints + for (std::vector::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::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 * diff --git a/src/snap.h b/src/snap.h index f740f3c62..c85c51963 100644 --- a/src/snap.h +++ b/src/snap.h @@ -129,6 +129,10 @@ public: Inkscape::Snapper::SnapConstraint const &constraint, Geom::OptRect const &bbox_to_snap = Geom::OptRect()) const; + Inkscape::SnappedPoint multipleConstrainedSnaps(Inkscape::SnapCandidatePoint const &p, + std::vector const &constraints, + Geom::OptRect const &bbox_to_snap = Geom::OptRect()) const; + void guideFreeSnap(Geom::Point &p, Geom::Point const &guide_normal, SPGuideDragType drag_type) const; void guideConstrainedSnap(Geom::Point &p, SPGuide const &guideline) const; diff --git a/src/snapped-point.h b/src/snapped-point.h index 05e954e1e..4b4882ee4 100644 --- a/src/snapped-point.h +++ b/src/snapped-point.h @@ -54,7 +54,9 @@ public: * has occurred; A check should be implemented in the calling code * to check for snapping. Use this method only when really needed, e.g. * when the calling code is trying to snap multiple points and must - * determine itself which point is most appropriate + * determine itself which point is most appropriate, or when doing a + * constrainedSnap that also enforces projection onto the constraint (in + * which case you need the new point anyway, even if we didn't snap) */ Geom::Point getPoint() const {return _point;} void setPoint(Geom::Point const &p) {_point = p;} diff --git a/src/ui/tool/node.cpp b/src/ui/tool/node.cpp index 69c09602e..a8582ccc5 100644 --- a/src/ui/tool/node.cpp +++ b/src/ui/tool/node.cpp @@ -270,9 +270,7 @@ void Handle::dragged(Geom::Point &new_pos, GdkEventMotion *event) _parent->position() - node_away->position()); Inkscape::SnappedPoint p; p = sm.constrainedSnap(Inkscape::SnapCandidatePoint(new_pos, SNAPSOURCE_NODE_HANDLE), cl); - if (p.getSnapped()) { - p.getPoint(new_pos); - } + new_pos = p.getPoint(); } else { sm.freeSnapReturnByRef(new_pos, SNAPSOURCE_NODE_HANDLE); } @@ -945,7 +943,7 @@ void Node::dragged(Geom::Point &new_pos, GdkEventMotion *event) // For a note on how snapping is implemented in Inkscape, see snap.h. SnapManager &sm = _desktop->namedview->snap_manager; bool snap = sm.someSnapperMightSnap(); - std::vector unselected; + Inkscape::SnappedPoint sp; if (snap) { /* setup * TODO We are doing this every time a snap happens. It should once be done only once @@ -955,6 +953,7 @@ void Node::dragged(Geom::Point &new_pos, GdkEventMotion *event) * TODO Snapping to unselected segments of selected paths doesn't work yet. */ // Build the list of unselected nodes. + std::vector unselected; typedef ControlPointSelection::Set Set; Set &nodes = _selection.allPoints(); for (Set::iterator i = nodes.begin(); i != nodes.end(); ++i) { @@ -964,32 +963,22 @@ void Node::dragged(Geom::Point &new_pos, GdkEventMotion *event) unselected.push_back(p); } } - sm.setupIgnoreSelection(_desktop, false, &unselected); + sm.setupIgnoreSelection(_desktop, true, &unselected); } if (held_control(*event)) { Geom::Point origin = _last_drag_origin(); - Inkscape::SnappedPoint fp, bp, fpp, bpp; + std::vector constraints; if (held_alt(*event)) { // with Ctrl+Alt, constrain to handle lines // project the new position onto a handle line that is closer; // also snap to perpendiculars of handle lines - // TODO: this code is repetitive to the point of sillyness. Find a way - // to express this concisely by modifying the semantics of snapping calls. - // During a non-snap invocation, we should call constrainedSnap() - // anyway, but it should just return the closest point matching the constraint - // rather than snapping to an object. There should be comparison - // operators defined for snap results, to simplify determining the best one, - // or the snapping calls should take a reference to a snapping result and - // replace it with the current result if it's better. - Inkscape::Preferences *prefs = Inkscape::Preferences::get(); int snaps = prefs->getIntLimited("/options/rotationsnapsperpi/value", 12, 1, 1000); double min_angle = M_PI / snaps; boost::optional front_point, back_point, fperp_point, bperp_point; - boost::optional line_front, line_back, line_fperp, line_bperp; if (_front.isDegenerate()) { if (_is_line_segment(this, _next())) front_point = _next()->position() - origin; @@ -1003,11 +992,11 @@ void Node::dragged(Geom::Point &new_pos, GdkEventMotion *event) back_point = _back.relativePos(); } if (front_point) { - line_front = Inkscape::Snapper::SnapConstraint(origin, *front_point); + constraints.push_back(Inkscape::Snapper::SnapConstraint(origin, *front_point)); fperp_point = Geom::rot90(*front_point); } if (back_point) { - line_back = Inkscape::Snapper::SnapConstraint(origin, *back_point); + constraints.push_back(Inkscape::Snapper::SnapConstraint(origin, *back_point)); bperp_point = Geom::rot90(*back_point); } // perpendiculars only snap when they are further than snap increment away @@ -1016,100 +1005,26 @@ void Node::dragged(Geom::Point &new_pos, GdkEventMotion *event) (fabs(Geom::angle_between(*fperp_point, *back_point)) > min_angle && fabs(Geom::angle_between(*fperp_point, *back_point)) < M_PI - min_angle))) { - line_fperp = Inkscape::Snapper::SnapConstraint(origin, *fperp_point); + constraints.push_back(Inkscape::Snapper::SnapConstraint(origin, *fperp_point)); } if (bperp_point && (!front_point || (fabs(Geom::angle_between(*bperp_point, *front_point)) > min_angle && fabs(Geom::angle_between(*bperp_point, *front_point)) < M_PI - min_angle))) { - line_bperp = Inkscape::Snapper::SnapConstraint(origin, *bperp_point); + constraints.push_back(Inkscape::Snapper::SnapConstraint(origin, *bperp_point)); } - // TODO: combine the snap and non-snap branches by modifying snap.h / snap.cpp - if (snap) { - if (line_front) { - fp = sm.constrainedSnap(Inkscape::SnapCandidatePoint(new_pos, - _snapSourceType()), *line_front); - } - if (line_back) { - bp = sm.constrainedSnap(Inkscape::SnapCandidatePoint(new_pos, - _snapSourceType()), *line_back); - } - if (line_fperp) { - fpp = sm.constrainedSnap(Inkscape::SnapCandidatePoint(new_pos, - _snapSourceType()), *line_fperp); - } - if (line_bperp) { - bpp = sm.constrainedSnap(Inkscape::SnapCandidatePoint(new_pos, - _snapSourceType()), *line_bperp); - } - } - if (fp.getSnapped() || bp.getSnapped() || fpp.getSnapped() || bpp.getSnapped()) { - if (fp.isOtherSnapBetter(bp, false)) { - fp = bp; - } - if (fp.isOtherSnapBetter(fpp, false)) { - fp = fpp; - } - if (fp.isOtherSnapBetter(bpp, false)) { - fp = bpp; - } - fp.getPoint(new_pos); - _desktop->snapindicator->set_new_snaptarget(fp); - } else { - boost::optional pos; - if (line_front) { - pos = line_front->projection(new_pos); - } - if (line_back) { - Geom::Point pos2 = line_back->projection(new_pos); - if (!pos || (pos && Geom::distance(new_pos, *pos) > Geom::distance(new_pos, pos2))) - pos = pos2; - } - if (line_fperp) { - Geom::Point pos2 = line_fperp->projection(new_pos); - if (!pos || (pos && Geom::distance(new_pos, *pos) > Geom::distance(new_pos, pos2))) - pos = pos2; - } - if (line_bperp) { - Geom::Point pos2 = line_bperp->projection(new_pos); - if (!pos || (pos && Geom::distance(new_pos, *pos) > Geom::distance(new_pos, pos2))) - pos = pos2; - } - if (pos) { - new_pos = *pos; - } else { - new_pos = origin; - } - } + sp = sm.multipleConstrainedSnaps(Inkscape::SnapCandidatePoint(new_pos, _snapSourceType()), constraints); } else { // with Ctrl, constrain to axes - // TODO combine the two branches - if (snap) { - Inkscape::Snapper::SnapConstraint line_x(origin, Geom::Point(1, 0)); - Inkscape::Snapper::SnapConstraint line_y(origin, Geom::Point(0, 1)); - fp = sm.constrainedSnap(Inkscape::SnapCandidatePoint(new_pos, _snapSourceType()), line_x); - bp = sm.constrainedSnap(Inkscape::SnapCandidatePoint(new_pos, _snapSourceType()), line_y); - } - if (fp.getSnapped() || bp.getSnapped()) { - if (fp.isOtherSnapBetter(bp, false)) { - fp = bp; - } - fp.getPoint(new_pos); - _desktop->snapindicator->set_new_snaptarget(fp); - } else { - Geom::Point origin = _last_drag_origin(); - Geom::Point delta = new_pos - origin; - Geom::Dim2 d = (fabs(delta[Geom::X]) < fabs(delta[Geom::Y])) ? Geom::X : Geom::Y; - new_pos[d] = origin[d]; - } + constraints.push_back(Inkscape::Snapper::SnapConstraint(origin, Geom::Point(1, 0))); + constraints.push_back(Inkscape::Snapper::SnapConstraint(origin, Geom::Point(0, 1))); + sp = sm.multipleConstrainedSnaps(Inkscape::SnapCandidatePoint(new_pos, _snapSourceType()), constraints); } + new_pos = sp.getPoint(); } else if (snap) { - Inkscape::SnappedPoint p = sm.freeSnap(Inkscape::SnapCandidatePoint(new_pos, _snapSourceType())); - if (p.getSnapped()) { - p.getPoint(new_pos); - _desktop->snapindicator->set_new_snaptarget(p); - } + sp = sm.freeSnap(Inkscape::SnapCandidatePoint(new_pos, _snapSourceType())); + new_pos = sp.getPoint(); } SelectableControlPoint::dragged(new_pos, event);