void Inkscape::LineSnapper::constrainedSnap(SnappedConstraints &sc,
Inkscape::SnapCandidatePoint const &p,
Geom::OptRect const &/*bbox_to_snap*/,
ConstraintLine const &c,
std::vector<SPItem const *> const */*it*/) const
{
if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(p.getSourceType()) == false) {
return;
}
/* Get the lines that we will try to snap to */
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::OptCrossing inters = Geom::OptCrossing(); // empty by default
try
{
inters = Geom::intersection(line1, line2);
}
catch (Geom::InfiniteSolutions e)
{
// We're probably dealing with parallel lines, so snapping doesn't make any sense here
continue; // jump to the next iterator in the for-loop
}
if (inters) {
Geom::Point t = line1.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
}
}
}
}
}
}
Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::SnapCandidatePoint const &p,
Inkscape::Snapper::SnapConstraint const &constraint,
Geom::OptRect const &bbox_to_snap) const
{
// First project the mouse pointer onto the constraint
Geom::Point pp = constraint.projection(p.getPoint());
Inkscape::SnappedPoint no_snap = Inkscape::SnappedPoint(pp, p.getSourceType(), p.getSourceNum(), Inkscape::SNAPTARGET_CONSTRAINT, Geom::infinity(), 0, false, true, false);
if (!someSnapperMightSnap()) {
// Always return point on constraint
return no_snap;
}
Inkscape::SnappedPoint result = no_snap;
Inkscape::Preferences *prefs = Inkscape::Preferences::get();
if ((prefs->getBool("/options/snapmousepointer/value", false)) && p.isSingleHandle()) {
// Snapping the mouse pointer instead of the constrained position of the knot allows
// to snap to things which don't intersect with the constraint line; this is basically
// then just a freesnap with the constraint applied afterwards
// We'll only do this if we're dragging a single handle, and for example not when transforming an object in the selector tool
result = freeSnap(p, bbox_to_snap);
if (result.getSnapped()) {
// only change the snap indicator if we really snapped to something
if (_snapindicator && _desktop) {
_desktop->snapindicator->set_new_snaptarget(result);
}
// Apply the constraint
result.setPoint(constraint.projection(result.getPoint()));
return result;
}
return no_snap;
}
IntermSnapResults isr;
SnapperList const snappers = getSnappers();
for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); ++i) {
(*i)->constrainedSnap(isr, p, bbox_to_snap, constraint, &_items_to_ignore, _unselected_nodes);
}
result = findBestSnap(p, isr, true);
if (result.getSnapped()) {
// only change the snap indicator if we really snapped to something
if (_snapindicator && _desktop) {
_desktop->snapindicator->set_new_snaptarget(result);
}
return result;
}
return no_snap;
}
void Inkscape::LineSnapper::freeSnap(SnappedConstraints &sc,
Inkscape::SnapCandidatePoint const &p,
Geom::OptRect const &/*bbox_to_snap*/,
std::vector<SPItem const *> const */*it*/,
std::vector<Inkscape::SnapCandidatePoint> */*unselected_nodes*/) const
{
if (!(_snap_enabled && _snapmanager->snapprefs.getSnapFrom(p.getSourceType())) ) {
return;
}
/* Get the lines that we will try to snap to */
const LineList lines = _getSnapLines(p.getPoint());
for (LineList::const_iterator i = lines.begin(); i != lines.end(); i++) {
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
// std::cout << " line through " << i->second << " with normal " << i->first;
g_assert(i->first != Geom::Point(0,0)); // we cannot project on an linesegment of zero length
Geom::Point const p_proj = Geom::projection(p.getPoint(), Geom::Line(p1, p2));
Geom::Coord const dist = Geom::L2(p_proj - p.getPoint());
//Store any line that's within snapping range
if (dist < getSnapperTolerance()) {
_addSnappedLine(sc, p_proj, dist, p.getSourceType(), p.getSourceNum(), i->first, i->second);
// 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(), false);
// Only relevant for guides; grids don't have an origin per line
// Therefore _addSnappedLinesOrigin() will only be implemented for guides
}
// std::cout << " -> distance = " << dist;
}
// std::cout << std::endl;
}
}
void Inkscape::LineSnapper::constrainedSnap(IntermSnapResults &isr,
Inkscape::SnapCandidatePoint const &p,
Geom::OptRect const &/*bbox_to_snap*/,
SnapConstraint const &c,
std::vector<SPItem const *> const */*it*/,
std::vector<SnapCandidatePoint> */*unselected_nodes*/) const
{
if (_snap_enabled == false || _snapmanager->snapprefs.isSourceSnappable(p.getSourceType()) == false) {
return;
}
// project the mouse pointer onto the constraint. Only the projected point will be considered for snapping
Geom::Point pp = c.projection(p.getPoint());
/* Get the lines that we will try to snap to */
const LineList lines = _getSnapLines(pp);
for (LineList::const_iterator i = lines.begin(); i != lines.end(); ++i) {
Geom::Point const point_on_line = c.hasPoint() ? c.getPoint() : pp;
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::Coord dist = Geom::L2(p_proj - origin); // distance from circle origin to constraint line
Geom::Coord radius = c.getRadius();
if (dist == radius) {
// Only one point of intersection;
_addSnappedPoint(isr, p_proj, Geom::L2(pp - p_proj), p.getSourceType(), p.getSourceNum(), true);
} 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;
_addSnappedPoint(isr, p_proj + v, Geom::L2(p.getPoint() - (p_proj + v)), p.getSourceType(), p.getSourceNum(), true);
_addSnappedPoint(isr, p_proj - v, Geom::L2(p.getPoint() - (p_proj - v)), p.getSourceType(), p.getSourceNum(), true);
}
}
} 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(constraint_line, gridguide_line);
}
catch (Geom::InfiniteSolutions &e)
{
// We're probably dealing with parallel lines, so snapping doesn't make any sense here
continue; // jump to the next iterator in the for-loop
}
if (inters) {
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(isr, t, dist, p.getSourceType(), p.getSourceNum(), true);
}
}
}
}
}
void Inkscape::LineSnapper::freeSnap(IntermSnapResults &isr,
Inkscape::SnapCandidatePoint const &p,
Geom::OptRect const &/*bbox_to_snap*/,
std::vector<SPItem const *> const */*it*/,
std::vector<Inkscape::SnapCandidatePoint> */*unselected_nodes*/) const
{
if (!(_snap_enabled && _snapmanager->snapprefs.isSourceSnappable(p.getSourceType())) ) {
return;
}
/* Get the lines that we will try to snap to */
const LineList lines = _getSnapLines(p.getPoint());
for (LineList::const_iterator i = lines.begin(); i != lines.end(); ++i) {
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
// std::cout << " line through " << i->second << " with normal " << i->first;
assert(i->first != Geom::Point(0,0)); // we cannot project on an linesegment of zero length
Geom::Point const p_proj = Geom::projection(p.getPoint(), Geom::Line(p1, p2));
Geom::Coord const dist = Geom::L2(p_proj - p.getPoint());
//Store any line that's within snapping range
if (dist < getSnapperTolerance()) {
_addSnappedLine(isr, p_proj, dist, p.getSourceType(), p.getSourceNum(), i->first, i->second);
// 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(isr, p1, dist_p1, p.getSourceType(), p.getSourceNum(), false);
// Only relevant for guides; grids don't have an origin per line
// Therefore _addSnappedLinesOrigin() will only be implemented for guides
}
// Here we will try to snap either tangentially or perpendicularly to a grid/guide line
// For this we need to know where the origin is located of the line that is currently being rotated,
std::vector<std::pair<Geom::Point, bool> > const origins_and_vectors = p.getOriginsAndVectors();
// Now we will iterate over all the origins and vectors and see which of these will get use a tangential or perpendicular snap
for (std::vector<std::pair<Geom::Point, bool> >::const_iterator it_origin_or_vector = origins_and_vectors.begin(); it_origin_or_vector != origins_and_vectors.end(); ++it_origin_or_vector) {
if ((*it_origin_or_vector).second) { // if "second" is true then "first" is a vector, otherwise it's a point
// When snapping a line with a constant vector (constant direction) to a guide or grid line,
// then either all points will be perpendicular/tangential or none at all. This is not very useful
continue;
}
//Geom::Point origin_doc = _snapmanager->getDesktop()->dt2doc((*it_origin_or_vector).first); // "first" contains a Geom::Point, denoting either a point
Geom::Point origin = (*it_origin_or_vector).first; // "first" contains a Geom::Point, denoting either a point
// We won't try to snap tangentially; a line being tangential to another line can be achieved by snapping both its endpoints
// individually to the other line. There's no need to have an explicit tangential snap here, that would be redundant
if (_snapmanager->snapprefs.getSnapPerp()) { // Find the point that leads to a perpendicular snap
Geom::Point const origin_proj = Geom::projection(origin, Geom::Line(p1, p2));
Geom::Coord dist = Geom::L2(origin_proj - p.getPoint());
if (dist < getSnapperTolerance()) {
_addSnappedLinePerpendicularly(isr, origin_proj, dist, p.getSourceType(), p.getSourceNum(), false);
}
}
}
// std::cout << " -> distance = " << dist;
}
// std::cout << std::endl;
}
}
Inkscape::SnappedPoint SnapManager::multipleConstrainedSnaps(Inkscape::SnapCandidatePoint const &p,
std::vector<Inkscape::Snapper::SnapConstraint> const &constraints,
bool dont_snap,
Geom::OptRect const &bbox_to_snap) const
{
Inkscape::SnappedPoint no_snap = Inkscape::SnappedPoint(p.getPoint(), p.getSourceType(), p.getSourceNum(), Inkscape::SNAPTARGET_CONSTRAINT, Geom::infinity(), 0, false, true, false);
if (constraints.size() == 0) {
return no_snap;
}
// We haven't tried to snap yet; we will first determine which constraint is closest to where we are now,
// i.e. lets find out which of the constraints yields the closest projection of point p
// Project the mouse pointer on each of the constraints
std::vector<Geom::Point> projections;
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);
}
// Select the closest constraint
no_snap.setPoint(projections.front());
Inkscape::Snapper::SnapConstraint cc = constraints.front(); //closest constraint
std::vector<Inkscape::Snapper::SnapConstraint>::const_iterator c = constraints.begin();
std::vector<Geom::Point>::iterator pp = projections.begin();
for (; pp != projections.end(); ++pp) {
if (Geom::L2(*pp - p.getPoint()) < Geom::L2(no_snap.getPoint() - p.getPoint())) {
no_snap.setPoint(*pp); // Remember the projection onto the closest constraint
cc = *c; // Remember the closest constraint itself
}
++c;
}
if (!someSnapperMightSnap() || dont_snap) {
return no_snap;
}
IntermSnapResults isr;
SnapperList const snappers = getSnappers();
Inkscape::Preferences *prefs = Inkscape::Preferences::get();
bool snap_mouse = prefs->getBool("/options/snapmousepointer/value", false);
Inkscape::SnappedPoint result = no_snap;
if (snap_mouse && p.isSingleHandle()) {
// Snapping the mouse pointer instead of the constrained position of the knot allows
// to snap to things which don't intersect with the constraint line; this is basically
// then just a freesnap with the constraint applied afterwards
// We'll only to this if we're dragging a single handle, and for example not when transforming an object in the selector tool
result = freeSnap(p, bbox_to_snap);
// Now apply the constraint afterwards
result.setPoint(cc.projection(result.getPoint()));
} else {
// Try to snap along the closest constraint
for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); ++i) {
(*i)->constrainedSnap(isr, p, bbox_to_snap, cc, &_items_to_ignore,_unselected_nodes);
}
result = findBestSnap(p, isr, true);
}
return result.getSnapped() ? result : no_snap;
}
