#include <2geom/line.h>

#include <cassert>

#include "line-snapper.h"

#include "snapped-line.h"

#include "snap.h"

Inkscape::LineSnapper::LineSnapper(SnapManager *sm, Geom::Coord const d) : Snapper(sm, d)

{

}

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;

}

}

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::_addSnappedLinesOrigin(IntermSnapResults &/*isr*/, Geom::Point const &/*origin*/, Geom::Coord const &/*snapped_distance*/, SnapSourceType const &/*source_type*/, long /*source_num*/, bool /*constrained_snap*/) const

{

}