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[inkscape.git] / src / line-snapper.cpp
index 5d5a772809d10163018394d3c8a7ea0b0028466f..22a964d43487e2b1e7c20851b0e43b458c532917 100644 (file)
@@ -22,22 +22,17 @@ Inkscape::LineSnapper::LineSnapper(SnapManager *sm, Geom::Coord const d) : Snapp
 }
 
 void Inkscape::LineSnapper::freeSnap(SnappedConstraints &sc,
-                                                    Inkscape::SnapPreferences::PointType const &t,
-                                                    Geom::Point const &p,
-                                                    SnapSourceType const &source_type,
-                                                    bool const &/*f*/,
+                                                    Inkscape::SnapCandidatePoint const &p,
                                                     Geom::OptRect const &/*bbox_to_snap*/,
                                                     std::vector<SPItem const *> const */*it*/,
-                                                    std::vector<std::pair<Geom::Point, int> > */*unselected_nodes*/) const
+                                                    std::vector<Inkscape::SnapCandidatePoint> */*unselected_nodes*/) const
 {
-    if (!(_snap_enabled && _snapmanager->snapprefs.getSnapFrom(t)) ) {
+    if (!(_snap_enabled && _snapmanager->snapprefs.getSnapFrom(p.getSourceType())) ) {
         return;
     }
 
     /* Get the lines that we will try to snap to */
-    const LineList lines = _getSnapLines(p);
-
-    // std::cout << "snap point " << p << " to: " << std::endl;
+    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
@@ -45,17 +40,17 @@ void Inkscape::LineSnapper::freeSnap(SnappedConstraints &sc,
         // 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, Geom::Line(p1, p2));
-        Geom::Coord const dist = Geom::L2(p_proj - p);
+        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, source_type, i->first, i->second);
+            _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);
+            Geom::Coord const dist_p1 = Geom::L2(p1 - p.getPoint());
             if (dist_p1 < getSnapperTolerance()) {
-                _addSnappedLinesOrigin(sc, p1, dist_p1, source_type);
+                _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
             }
@@ -66,37 +61,55 @@ void Inkscape::LineSnapper::freeSnap(SnappedConstraints &sc,
 }
 
 void Inkscape::LineSnapper::constrainedSnap(SnappedConstraints &sc,
-                                               Inkscape::SnapPreferences::PointType const &t,
-                                               Geom::Point const &p,
-                                               SnapSourceType const &source_type,
-                                               bool const &/*f*/,
+                                               Inkscape::SnapCandidatePoint const &p,
                                                Geom::OptRect const &/*bbox_to_snap*/,
-                                               ConstraintLine const &c,
-                                               std::vector<SPItem const *> const */*it*/) const
+                                               SnapConstraint const &c,
+                                               std::vector<SPItem const *> const */*it*/,
+                                               std::vector<SnapCandidatePoint> */*unselected_nodes*/) const
 
 {
-    if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(t) == false) {
+    if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(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(p);
+    const LineList lines = _getSnapLines(pp);
 
     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;
-            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::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(sc, 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(sc, p_proj + v, Geom::L2(p.getPoint() - (p_proj + v)), p.getSourceType(), p.getSourceNum(), true);
+                    _addSnappedPoint(sc, 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(line1, line2);
+                inters = Geom::intersection(constraint_line, gridguide_line);
             }
             catch (Geom::InfiniteSolutions e)
             {
@@ -105,23 +118,14 @@ void Inkscape::LineSnapper::constrainedSnap(SnappedConstraints &sc,
             }
 
             if (inters) {
-                Geom::Point t = line1.pointAt((*inters).ta);
-                const Geom::Coord dist = Geom::L2(t - p);
+                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(sc, t, dist, source_type);
-                    // 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);
-                    if (dist_p1 < getSnapperTolerance()) {
-                        _addSnappedLinesOrigin(sc, p1, dist_p1, source_type);
-                        // Only relevant for guides; grids don't have an origin per line
-                        // Therefore _addSnappedLinesOrigin() will only be implemented for guides
-                    }
+                    _addSnappedPoint(sc, t, dist, p.getSourceType(), p.getSourceNum(), true);
                 }
             }
         }
@@ -130,7 +134,7 @@ void Inkscape::LineSnapper::constrainedSnap(SnappedConstraints &sc,
 
 // Will only be overridden in the guide-snapper class, because grid lines don't have an origin; the
 // grid-snapper classes will use this default empty method
-void Inkscape::LineSnapper::_addSnappedLinesOrigin(SnappedConstraints &/*sc*/, Geom::Point const /*origin*/, Geom::Coord const /*snapped_distance*/, SnapSourceType const &/*source_type*/) const
+void Inkscape::LineSnapper::_addSnappedLinesOrigin(SnappedConstraints &/*sc*/, Geom::Point const /*origin*/, Geom::Coord const /*snapped_distance*/, SnapSourceType const &/*source_type*/, long /*source_num*/, bool /*constrained_snap*/) const
 {
 }