X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=src%2Fnodepath.cpp;h=b712539ab767f78f872a3fb550c54095ae7f1f9f;hb=144c1b594591ba3d62513b126ca87a5f242b2f2b;hp=924d57595be1993cd3452c8e60cf5d6f5fe82d7e;hpb=b646aaae3a1f344f077bf9ac5d364663dad89ebe;p=inkscape.git

diff --git a/src/nodepath.cpp b/src/nodepath.cpp
index 924d57595..b712539ab 100644
--- a/src/nodepath.cpp
+++ b/src/nodepath.cpp
@@ -19,6 +19,7 @@
 #include "display/curve.h"
 #include "display/sp-ctrlline.h"
 #include "display/sodipodi-ctrl.h"
+#include "display/sp-canvas-util.h"
 #include <glibmm/i18n.h>
 #include "libnr/n-art-bpath.h"
 #include "libnr/nr-path.h"
@@ -50,9 +51,11 @@
 #include <cstring>
 #include <string>
 #include "live_effects/lpeobject.h"
+#include "live_effects/effect.h"
 #include "live_effects/parameter/parameter.h"
 #include "util/mathfns.h"
 #include "display/snap-indicator.h"
+#include "snapped-point.h"
 
 class NR::Matrix;
 
@@ -92,7 +95,7 @@ static GMemChunk *nodechunk = NULL;
 
 /* Creation from object */
 
-static NArtBpath *subpath_from_bpath(Inkscape::NodePath::Path *np, NArtBpath *b, gchar const *t);
+static NArtBpath const * subpath_from_bpath(Inkscape::NodePath::Path *np, NArtBpath const *b, gchar const *t);
 static gchar *parse_nodetypes(gchar const *types, gint length);
 
 /* Object updating */
@@ -149,6 +152,20 @@ static void sp_nodepath_set_curve (Inkscape::NodePath::Path *np, SPCurve *curve)
 // active_node indicates mouseover node
 Inkscape::NodePath::Node * Inkscape::NodePath::Path::active_node = NULL;
 
+static void sp_nodepath_draw_helper_curve(Inkscape::NodePath::Path *np, SPDesktop *desktop) {
+    // Draw helper curve
+    if (np->show_helperpath) {
+        SPCurve *helper_curve = np->curve->copy();
+        helper_curve->transform(np->i2d );
+        np->helper_path = sp_canvas_bpath_new(sp_desktop_controls(desktop), helper_curve);
+        sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(np->helper_path), np->helperpath_rgba, np->helperpath_width, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
+        sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(np->helper_path), 0, SP_WIND_RULE_NONZERO);
+        sp_canvas_item_move_to_z(np->helper_path, 0);
+        sp_canvas_item_show(np->helper_path);
+        helper_curve->unref();
+    }
+}
+
 /**
  * \brief Creates new nodepath from item
  */
@@ -178,17 +195,17 @@ Inkscape::NodePath::Path *sp_nodepath_new(SPDesktop *desktop, SPObject *object,
     if (curve == NULL)
         return NULL;
 
-    NArtBpath *bpath = sp_curve_first_bpath(curve);
-    gint length = curve->end;
+    NArtBpath const *bpath = curve->get_bpath();
+    gint length = curve->get_length();
     if (length == 0) {
-        sp_curve_unref(curve);
+        curve->unref();
         return NULL; // prevent crash for one-node paths
     }
 
     //Create new nodepath
     Inkscape::NodePath::Path *np = g_new(Inkscape::NodePath::Path, 1);
     if (!np) {
-        sp_curve_unref(curve);
+        curve->unref();
         return NULL;
     }
 
@@ -204,8 +221,14 @@ Inkscape::NodePath::Path *sp_nodepath_new(SPDesktop *desktop, SPObject *object,
     np->helper_path = NULL;
     np->helperpath_rgba = prefs_get_int_attribute("tools.nodes", "highlight_color", 0xff0000ff);
     np->helperpath_width = 1.0;
-    np->curve = sp_curve_copy(curve);
-    np->show_helperpath = prefs_get_int_attribute ("tools.nodes", "show_helperpath",  0) == 1;
+    np->curve = curve->copy();
+    np->show_helperpath = (prefs_get_int_attribute ("tools.nodes", "show_helperpath",  0) == 1);
+    if (SP_IS_LPE_ITEM(object)) {
+        Inkscape::LivePathEffect::Effect *lpe = sp_lpe_item_get_current_lpe(SP_LPE_ITEM(object));
+        if (lpe && lpe->isVisible() && lpe->showOrigPath()) {
+            np->show_helperpath = true;
+        }            
+    }
     np->straight_path = false;
     if (IS_LIVEPATHEFFECT(object) && item) {
         np->item = item;
@@ -218,7 +241,7 @@ Inkscape::NodePath::Path *sp_nodepath_new(SPDesktop *desktop, SPObject *object,
     // to a change in repr by regenerating nodepath     --bb
     sp_object_read_attr(SP_OBJECT(np->item), "transform");
 
-    np->i2d  = sp_item_i2d_affine(np->item);
+    np->i2d  = from_2geom(sp_item_i2d_affine(np->item));
     np->d2i  = np->i2d.inverse();
 
     np->repr = repr;
@@ -234,9 +257,9 @@ Inkscape::NodePath::Path *sp_nodepath_new(SPDesktop *desktop, SPObject *object,
         if ( sp_lpe_item_has_path_effect_recursive(SP_LPE_ITEM(np->object)) ) {
             np->repr_key = g_strdup("inkscape:original-d");
 
-            LivePathEffectObject *lpeobj = sp_lpe_item_get_livepatheffectobject(SP_LPE_ITEM(np->object));
-            if (lpeobj && lpeobj->lpe) {
-                lpeobj->lpe->setup_nodepath(np);
+            Inkscape::LivePathEffect::Effect* lpe = sp_lpe_item_get_current_lpe(SP_LPE_ITEM(np->object));
+            if (lpe) {
+                lpe->setup_nodepath(np);
             }
         } else {
             np->repr_key = g_strdup("d");
@@ -247,7 +270,7 @@ Inkscape::NodePath::Path *sp_nodepath_new(SPDesktop *desktop, SPObject *object,
     gchar *typestr = parse_nodetypes(nodetypes, length);
 
     // create the subpath(s) from the bpath
-    NArtBpath *b = bpath;
+    NArtBpath const *b = bpath;
     while (b->code != NR_END) {
         b = subpath_from_bpath(np, b, typestr + (b - bpath));
     }
@@ -256,21 +279,12 @@ Inkscape::NodePath::Path *sp_nodepath_new(SPDesktop *desktop, SPObject *object,
     np->subpaths = g_list_reverse(np->subpaths);
 
     g_free(typestr);
-    sp_curve_unref(curve);
+    curve->unref();
 
     // create the livarot representation from the same item
     sp_nodepath_ensure_livarot_path(np);
 
-    // Draw helper curve
-    if (np->show_helperpath) {
-        SPCurve *helper_curve = sp_curve_copy(np->curve);
-        sp_curve_transform(helper_curve, np->i2d );
-        np->helper_path = sp_canvas_bpath_new(sp_desktop_controls(desktop), helper_curve);
-        sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(np->helper_path), np->helperpath_rgba, np->helperpath_width, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
-        sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(np->helper_path), 0, SP_WIND_RULE_NONZERO);
-        sp_canvas_item_show(np->helper_path);
-        sp_curve_unref(helper_curve);
-    }
+    sp_nodepath_draw_helper_curve(np, desktop);
 
     return np;
 }
@@ -304,7 +318,7 @@ void sp_nodepath_destroy(Inkscape::NodePath::Path *np) {
         gtk_object_destroy(temp);
     }
     if (np->curve) {
-        sp_curve_unref(np->curve);
+        np->curve->unref();
         np->curve = NULL;
     }
 
@@ -327,13 +341,13 @@ void sp_nodepath_ensure_livarot_path(Inkscape::NodePath::Path *np)
 {
     if (np && np->livarot_path == NULL) {
         SPCurve *curve = create_curve(np);
-        NArtBpath *bpath = SP_CURVE_BPATH(curve);
-        np->livarot_path = bpath_to_Path(bpath);
+        np->livarot_path = new Path;
+        np->livarot_path->LoadPathVector(curve->get_pathvector());
 
         if (np->livarot_path)
             np->livarot_path->ConvertWithBackData(0.01);
 
-        sp_curve_unref(curve);
+        curve->unref();
     }
 }
 
@@ -440,7 +454,7 @@ static void sp_nodepath_cleanup(Inkscape::NodePath::Path *nodepath)
  * \param t The node type.
  * \todo Fixme: t should be a proper type, rather than gchar
  */
-static NArtBpath *subpath_from_bpath(Inkscape::NodePath::Path *np, NArtBpath *b, gchar const *t)
+static NArtBpath const * subpath_from_bpath(Inkscape::NodePath::Path *np, NArtBpath const *b, gchar const *t)
 {
     NR::Point ppos, pos, npos;
 
@@ -530,16 +544,16 @@ static void update_object(Inkscape::NodePath::Path *np)
 {
     g_assert(np);
 
-    sp_curve_unref(np->curve);
+    np->curve->unref();
     np->curve = create_curve(np);
 
     sp_nodepath_set_curve(np, np->curve);
 
     if (np->show_helperpath) {
-        SPCurve * helper_curve = sp_curve_copy(np->curve);
-        sp_curve_transform(helper_curve, np->i2d );
+        SPCurve * helper_curve = np->curve->copy();
+        helper_curve->transform(np->i2d );
         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(np->helper_path), helper_curve);
-        sp_curve_unref(helper_curve);
+        helper_curve->unref();
     }
 }
 
@@ -552,11 +566,11 @@ static void update_repr_internal(Inkscape::NodePath::Path *np)
 
     Inkscape::XML::Node *repr = np->object->repr;
 
-    sp_curve_unref(np->curve);
+    np->curve->unref();
     np->curve = create_curve(np);
 
     gchar *typestr = create_typestr(np);
-    gchar *svgpath = sp_svg_write_path(SP_CURVE_BPATH(np->curve));
+    gchar *svgpath = sp_svg_write_path(np->curve->get_pathvector());
 
     // determine if path has an effect applied and write to correct "d" attribute.
     if (repr->attribute(np->repr_key) == NULL || strcmp(svgpath, repr->attribute(np->repr_key))) { // d changed
@@ -573,10 +587,10 @@ static void update_repr_internal(Inkscape::NodePath::Path *np)
     g_free(typestr);
 
     if (np->show_helperpath) {
-        SPCurve * helper_curve = sp_curve_copy(np->curve);
-        sp_curve_transform(helper_curve, np->i2d );
+        SPCurve * helper_curve = np->curve->copy();
+        helper_curve->transform(np->i2d );
         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(np->helper_path), helper_curve);
-        sp_curve_unref(helper_curve);
+        helper_curve->unref();
     }
  }
 
@@ -633,7 +647,7 @@ static void stamp_repr(Inkscape::NodePath::Path *np)
     SPCurve *curve = create_curve(np);
     gchar *typestr = create_typestr(np);
 
-    gchar *svgpath = sp_svg_write_path(SP_CURVE_BPATH(curve));
+    gchar *svgpath = sp_svg_write_path(curve->get_pathvector());
 
     new_repr->setAttribute(np->repr_key, svgpath);
     new_repr->setAttribute(np->repr_nodetypes_key, typestr);
@@ -649,7 +663,7 @@ static void stamp_repr(Inkscape::NodePath::Path *np)
     Inkscape::GC::release(new_repr);
     g_free(svgpath);
     g_free(typestr);
-    sp_curve_unref(curve);
+    curve->unref();
 }
 
 /**
@@ -657,22 +671,20 @@ static void stamp_repr(Inkscape::NodePath::Path *np)
  */
 static SPCurve *create_curve(Inkscape::NodePath::Path *np)
 {
-    SPCurve *curve = sp_curve_new();
+    SPCurve *curve = new SPCurve();
 
     for (GList *spl = np->subpaths; spl != NULL; spl = spl->next) {
        Inkscape::NodePath::SubPath *sp = (Inkscape::NodePath::SubPath *) spl->data;
-        sp_curve_moveto(curve,
-                        sp->first->pos * np->d2i);
+        curve->moveto(sp->first->pos * np->d2i);
        Inkscape::NodePath::Node *n = sp->first->n.other;
         while (n) {
             NR::Point const end_pt = n->pos * np->d2i;
             switch (n->code) {
                 case NR_LINETO:
-                    sp_curve_lineto(curve, end_pt);
+                    curve->lineto(end_pt);
                     break;
                 case NR_CURVETO:
-                    sp_curve_curveto(curve,
-                                     n->p.other->n.pos * np->d2i,
+                    curve->curveto(n->p.other->n.pos * np->d2i,
                                      n->p.pos * np->d2i,
                                      end_pt);
                     break;
@@ -687,7 +699,7 @@ static SPCurve *create_curve(Inkscape::NodePath::Path *np)
             }
         }
         if (sp->closed) {
-            sp_curve_closepath(curve);
+            curve->closepath();
         }
     }
 
@@ -967,9 +979,6 @@ static Inkscape::NodePath::Node *sp_nodepath_set_node_type(Inkscape::NodePath::N
     g_assert(node);
     g_assert(node->subpath);
 
-    if (type == static_cast<Inkscape::NodePath::NodeType>(static_cast< guint >(node->type) ) )
-        return node;
-
     if ((node->p.other != NULL) && (node->n.other != NULL)) {
         if ((node->code == NR_LINETO) && (node->n.other->code == NR_LINETO)) {
             type =Inkscape::NodePath::NODE_CUSP;
@@ -1004,48 +1013,157 @@ static Inkscape::NodePath::Node *sp_nodepath_set_node_type(Inkscape::NodePath::N
     return node;
 }
 
+bool
+sp_node_side_is_line (Inkscape::NodePath::Node *node, Inkscape::NodePath::NodeSide *side)
+{
+        Inkscape::NodePath::Node *othernode = side->other;
+        if (!othernode)
+            return false;
+        NRPathcode const code = sp_node_path_code_from_side(node, side);
+        if (code == NR_LINETO)
+            return true;
+        Inkscape::NodePath::NodeSide *other_to_me = NULL;
+        if (&node->p == side) {
+            other_to_me = &othernode->n;
+        } else if (&node->n == side) {
+            other_to_me = &othernode->p;
+        } 
+        if (!other_to_me)
+            return false;
+        bool is_line = 
+             (NR::L2(othernode->pos - other_to_me->pos) < 1e-6 &&
+              NR::L2(node->pos - side->pos) < 1e-6);
+        return is_line;
+}
+
 /**
- * Same as sp_nodepath_set_node_type(), but also converts, if necessary,
- * adjacent segments from lines to curves.
+ * Same as sp_nodepath_set_node_type(), but also converts, if necessary, adjacent segments from
+ * lines to curves.  If adjacent to one line segment, pulls out or rotates opposite handle to align
+ * with that segment, procucing half-smooth node. If already half-smooth, pull out the second handle too. 
+ * If already cusp and set to cusp, retracts handles.
 */
 void sp_nodepath_convert_node_type(Inkscape::NodePath::Node *node, Inkscape::NodePath::NodeType type)
 {
-    bool p_line = (node->p.other != NULL) && (node->code == NR_LINETO || node->pos == node->p.pos);
-    bool n_line = (node->n.other != NULL) && (node->n.other->code == NR_LINETO || node->pos == node->n.pos);
-
     if (type == Inkscape::NodePath::NODE_SYMM || type == Inkscape::NodePath::NODE_SMOOTH) {
-        if (p_line && n_line) {
-            // only if both adjacent segments are lines,
-            // convert both to curves:
 
-            node->code = NR_CURVETO;
-            node->n.other->code = NR_CURVETO;
+/* 
+  Here's the algorithm of converting node to smooth (Shift+S or toolbar button), in pseudocode:
+ 
+        if (two_handles) {
+            // do nothing, adjust_handles called via set_node_type will line them up
+        } else if (one_handle) {
+            if (opposite_to_handle_is_line) {
+                if (lined_up) {
+                    // already half-smooth; pull opposite handle too making it fully smooth
+                } else {
+                    // do nothing, adjust_handles will line the handle  up, producing a half-smooth node
+                }
+            } else {
+                // pull opposite handle in line with the existing one
+            }
+        } else if (no_handles) {
+            if (both_segments_are_lines OR both_segments_are_curves) {
+                //pull both handles
+            } else {
+                // pull the handle opposite to line segment, making node half-smooth
+            }
+        }
+*/
+        bool p_has_handle = (NR::L2(node->pos  - node->p.pos) > 1e-6);
+        bool n_has_handle = (NR::L2(node->pos  - node->n.pos) > 1e-6);
+        bool p_is_line = sp_node_side_is_line(node, &node->p);
+        bool n_is_line = sp_node_side_is_line(node, &node->n);
+
+        if (p_has_handle && n_has_handle) {
+            // do nothing, adjust_handles will line them up
+        } else if (p_has_handle || n_has_handle) {
+            if (p_has_handle && n_is_line) {
+                Radial line (node->n.other->pos - node->pos);
+                Radial handle (node->pos - node->p.pos);
+                if (fabs(line.a - handle.a) < 1e-3) { // lined up
+                    // already half-smooth; pull opposite handle too making it fully smooth
+                    node->n.pos = node->pos + (node->n.other->pos - node->pos) / 3;
+                } else {
+                    // do nothing, adjust_handles will line the handle  up, producing a half-smooth node
+                }
+            } else if (n_has_handle && p_is_line) {
+                Radial line (node->p.other->pos - node->pos);
+                Radial handle (node->pos - node->n.pos);
+                if (fabs(line.a - handle.a) < 1e-3) { // lined up
+                    // already half-smooth; pull opposite handle too making it fully smooth
+                    node->p.pos = node->pos + (node->p.other->pos - node->pos) / 3;
+                } else {
+                    // do nothing, adjust_handles will line the handle  up, producing a half-smooth node
+                }
+            } else if (p_has_handle && node->n.other) {
+                // pull n handle
+                node->n.other->code = NR_CURVETO;
+                double len =  (type == Inkscape::NodePath::NODE_SYMM)?
+                    NR::L2(node->p.pos - node->pos) :
+                    NR::L2(node->n.other->pos - node->pos) / 3;
+                node->n.pos = node->pos - (len / NR::L2(node->p.pos - node->pos)) * (node->p.pos - node->pos);
+            } else if (n_has_handle && node->p.other) {
+                // pull p handle
+                node->code = NR_CURVETO;
+                double len =  (type == Inkscape::NodePath::NODE_SYMM)?
+                    NR::L2(node->n.pos - node->pos) :
+                    NR::L2(node->p.other->pos - node->pos) / 3;
+                node->p.pos = node->pos - (len / NR::L2(node->n.pos - node->pos)) * (node->n.pos - node->pos);
+            }
+        } else if (!p_has_handle && !n_has_handle) {
+            if ((p_is_line && n_is_line) || (!p_is_line && node->p.other && !n_is_line && node->n.other)) {
+                // no handles, but both segments are either lnes or curves:
+                //pull both handles
+
+                // convert both to curves:
+                node->code = NR_CURVETO;
+                node->n.other->code = NR_CURVETO;
 
-            NR::Point leg_prev = node->pos - node->p.other->pos;
-            NR::Point leg_next = node->pos - node->n.other->pos;
+                NR::Point leg_prev = node->pos - node->p.other->pos;
+                NR::Point leg_next = node->pos - node->n.other->pos;
 
-            double norm_leg_prev = L2(leg_prev);
-            double norm_leg_next = L2(leg_next);
+                double norm_leg_prev = L2(leg_prev);
+                double norm_leg_next = L2(leg_next);
 
-            // delta has length 1 and is orthogonal to bisecting line
-            NR::Point delta;
-            if (norm_leg_next > 0.0) {
-                delta = (norm_leg_prev / norm_leg_next) * leg_next - leg_prev;
-                (&delta)->normalize();
-            }
+                NR::Point delta;
+                if (norm_leg_next > 0.0) {
+                    delta = (norm_leg_prev / norm_leg_next) * leg_next - leg_prev;
+                    (&delta)->normalize();
+                }
+
+                if (type == Inkscape::NodePath::NODE_SYMM) {
+                    double norm_leg_avg = (norm_leg_prev + norm_leg_next) / 2;
+                    node->p.pos = node->pos + 0.3 * norm_leg_avg * delta;
+                    node->n.pos = node->pos - 0.3 * norm_leg_avg * delta;
+                } else {
+                    // length of handle is proportional to distance to adjacent node
+                    node->p.pos = node->pos + 0.3 * norm_leg_prev * delta;
+                    node->n.pos = node->pos - 0.3 * norm_leg_next * delta;
+                }
 
-            if (type == Inkscape::NodePath::NODE_SYMM) {
-                double norm_leg_avg = (norm_leg_prev + norm_leg_next) / 2;
-                node->p.pos = node->pos + 0.3 * norm_leg_avg * delta;
-                node->n.pos = node->pos - 0.3 * norm_leg_avg * delta;
             } else {
-                // length of handle is proportional to distance to adjacent node
-                node->p.pos = node->pos + 0.3 * norm_leg_prev * delta;
-                node->n.pos = node->pos - 0.3 * norm_leg_next * delta;
+                // pull the handle opposite to line segment, making it half-smooth
+                if (p_is_line && node->n.other) {
+                    if (type != Inkscape::NodePath::NODE_SYMM) {
+                        // pull n handle
+                        node->n.other->code = NR_CURVETO;
+                        double len =  NR::L2(node->n.other->pos - node->pos) / 3;
+                        node->n.pos = node->pos + (len / NR::L2(node->p.other->pos - node->pos)) * (node->p.other->pos - node->pos);
+                    }
+                } else if (n_is_line && node->p.other) {
+                    if (type != Inkscape::NodePath::NODE_SYMM) {
+                        // pull p handle
+                        node->code = NR_CURVETO;
+                        double len =  NR::L2(node->p.other->pos - node->pos) / 3;
+                        node->p.pos = node->pos + (len / NR::L2(node->n.other->pos - node->pos)) * (node->n.other->pos - node->pos);
+                    }
+                }
             }
-
-            sp_node_update_handles(node);
         }
+    } else if (type == Inkscape::NodePath::NODE_CUSP && node->type == Inkscape::NodePath::NODE_CUSP) {
+        // cusping a cusp: retract nodes
+        node->p.pos = node->pos;
+        node->n.pos = node->pos;
     }
 
     sp_nodepath_set_node_type (node, type);
@@ -1095,13 +1213,13 @@ void sp_node_moveto(Inkscape::NodePath::Node *node, NR::Point p)
  * Call sp_node_moveto() for node selection and handle possible snapping.
  */
 static void sp_nodepath_selected_nodes_move(Inkscape::NodePath::Path *nodepath, NR::Coord dx, NR::Coord dy,
-                                            bool const snap = true)
+                                            bool const snap, bool constrained = false, 
+                                            Inkscape::Snapper::ConstraintLine const &constraint = NR::Point())
 {
     NR::Coord best = NR_HUGE;
     NR::Point delta(dx, dy);
     NR::Point best_pt = delta;
-    NR::Point best_abs(NR_HUGE, NR_HUGE);
-
+    Inkscape::SnappedPoint best_abs;
     
     if (snap) {    
         /* When dragging a (selected) node, it should only snap to other nodes (i.e. unselected nodes), and
@@ -1124,16 +1242,26 @@ static void sp_nodepath_selected_nodes_move(Inkscape::NodePath::Path *nodepath,
         
         for (GList *l = nodepath->selected; l != NULL; l = l->next) {
             Inkscape::NodePath::Node *n = (Inkscape::NodePath::Node *) l->data;
-            Inkscape::SnappedPoint s = m.freeSnap(Inkscape::Snapper::SNAPPOINT_NODE, n->pos + delta, SP_PATH(n->subpath->nodepath->item), &unselected_nodes);            
-            if (s.getDistance() < best) {
+            m.setup(NULL, SP_PATH(n->subpath->nodepath->item), &unselected_nodes);
+            Inkscape::SnappedPoint s;
+            if (constrained) {
+                Inkscape::Snapper::ConstraintLine dedicated_constraint = constraint;
+                dedicated_constraint.setPoint(n->pos);
+                s = m.constrainedSnap(Inkscape::Snapper::SNAPPOINT_NODE, n->pos + delta, dedicated_constraint);
+            } else {
+                s = m.freeSnap(Inkscape::Snapper::SNAPPOINT_NODE, n->pos + delta);
+            }            
+            if (s.getSnapped() && (s.getDistance() < best)) {
                 best = s.getDistance();
-                best_abs = s.getPoint();
-                best_pt = best_abs - n->pos;
+                best_abs = s;
+                best_pt = s.getPoint() - n->pos;
             }
         }
                         
-        if (best_abs[NR::X] < NR_HUGE) {
-            nodepath->desktop->snapindicator->set_new_snappoint(best_abs.to_2geom());
+        if (best_abs.getSnapped()) {
+            nodepath->desktop->snapindicator->set_new_snappoint(best_abs);
+        } else {
+            nodepath->desktop->snapindicator->remove_snappoint();    
         }
     }
 
@@ -1913,12 +2041,14 @@ static void do_node_selected_join(Inkscape::NodePath::Path *nodepath, Inkscape::
 {
     /* a and b are endpoints */
 
+    // if one of the two nodes is mouseovered, fix its position
     NR::Point c;
     if (a->knot && SP_KNOT_IS_MOUSEOVER(a->knot)) {
         c = a->pos;
     } else if (b->knot && SP_KNOT_IS_MOUSEOVER(b->knot)) {
         c = b->pos;
     } else {
+        // otherwise, move joined node to the midpoint
         c = (a->pos + b->pos) / 2;
     }
 
@@ -1939,20 +2069,27 @@ static void do_node_selected_join(Inkscape::NodePath::Path *nodepath, Inkscape::
     Inkscape::NodePath::Node *n;
     NRPathcode code;
     if (a == sa->first) {
+        // we will now reverse sa, so that a is its last node, not first, and drop that node
         p = sa->first->n.pos;
         code = (NRPathcode)sa->first->n.other->code;
+        // create new subpath
        Inkscape::NodePath::SubPath *t = sp_nodepath_subpath_new(sa->nodepath);
+       // create a first moveto node on it
         n = sa->last;
         sp_nodepath_node_new(t, NULL,Inkscape::NodePath::NODE_CUSP, NR_MOVETO, &n->n.pos, &n->pos, &n->p.pos);
         n = n->p.other;
+        if (n == sa->first) n = NULL;
         while (n) {
+            // copy the rest of the nodes from sa to t, going backwards
             sp_nodepath_node_new(t, NULL, (Inkscape::NodePath::NodeType)n->type, (NRPathcode)n->n.other->code, &n->n.pos, &n->pos, &n->p.pos);
             n = n->p.other;
             if (n == sa->first) n = NULL;
         }
+        // replace sa with t
         sp_nodepath_subpath_destroy(sa);
         sa = t;
     } else if (a == sa->last) {
+        // a is already last, just drop it
         p = sa->last->p.pos;
         code = (NRPathcode)sa->last->code;
         sp_nodepath_node_destroy(sa->last);
@@ -1962,11 +2099,13 @@ static void do_node_selected_join(Inkscape::NodePath::Path *nodepath, Inkscape::
     }
 
     if (b == sb->first) {
+        // copy all nodes from b to a, forward 
         sp_nodepath_node_new(sa, NULL,Inkscape::NodePath::NODE_CUSP, code, &p, &c, &sb->first->n.pos);
         for (n = sb->first->n.other; n != NULL; n = n->n.other) {
             sp_nodepath_node_new(sa, NULL, (Inkscape::NodePath::NodeType)n->type, (NRPathcode)n->code, &n->p.pos, &n->pos, &n->n.pos);
         }
     } else if (b == sb->last) {
+        // copy all nodes from b to a, backward 
         sp_nodepath_node_new(sa, NULL,Inkscape::NodePath::NODE_CUSP, code, &p, &c, &sb->last->p.pos);
         for (n = sb->last->p.other; n != NULL; n = n->p.other) {
             sp_nodepath_node_new(sa, NULL, (Inkscape::NodePath::NodeType)n->type, (NRPathcode)n->n.other->code, &n->n.pos, &n->pos, &n->p.pos);
@@ -2201,8 +2340,10 @@ void sp_node_delete_preserve(GList *nodes_to_delete)
             //if these nodes are smooth or symmetrical, the endpoints will be thrown out of sync.
             //make sure these nodes are changed to cusp nodes so that, once the endpoints are moved,
             //the resulting nodes behave as expected.
-            sp_nodepath_convert_node_type(sample_cursor, Inkscape::NodePath::NODE_CUSP);
-            sp_nodepath_convert_node_type(sample_end, Inkscape::NodePath::NODE_CUSP);
+            if (sample_cursor->type != Inkscape::NodePath::NODE_CUSP)
+                sp_nodepath_convert_node_type(sample_cursor, Inkscape::NodePath::NODE_CUSP);
+            if (sample_end->type != Inkscape::NodePath::NODE_CUSP)
+                sp_nodepath_convert_node_type(sample_end, Inkscape::NodePath::NODE_CUSP);
 
             //adjust endpoints
             sample_cursor->n.pos = bez[1];
@@ -2951,53 +3092,41 @@ void restore_nodepath_selection(Inkscape::NodePath::Path *nodepath, GList *r)
             }
         }
     }
-
 }
 
+
 /**
 \brief Adjusts handle according to node type and line code.
 */
 static void sp_node_adjust_handle(Inkscape::NodePath::Node *node, gint which_adjust)
 {
-    double len, otherlen, linelen;
-
     g_assert(node);
 
    Inkscape::NodePath::NodeSide *me = sp_node_get_side(node, which_adjust);
    Inkscape::NodePath::NodeSide *other = sp_node_opposite_side(node, me);
 
-    /** \todo fixme: */
+   // nothing to do if we are an end node
     if (me->other == NULL) return;
     if (other->other == NULL) return;
 
-    /* I have line */
+    // nothing to do if we are a cusp node
+    if (node->type == Inkscape::NodePath::NODE_CUSP) return;
 
-    NRPathcode mecode, ocode;
+    // nothing to do if it's a line from the specified side of the node (i.e. no handle to adjust)
+    NRPathcode mecode;
     if (which_adjust == 1) {
         mecode = (NRPathcode)me->other->code;
-        ocode = (NRPathcode)node->code;
     } else {
         mecode = (NRPathcode)node->code;
-        ocode = (NRPathcode)other->other->code;
     }
-
     if (mecode == NR_LINETO) return;
 
-    /* I am curve */
-
-    if (other->other == NULL) return;
-
-    /* Other has line */
-
-    if (node->type == Inkscape::NodePath::NODE_CUSP) return;
-
-    NR::Point delta;
-    if (ocode == NR_LINETO) {
-        /* other is lineto, we are either smooth or symm */
+    if (sp_node_side_is_line(node, other)) {
+        // other is a line, and we are either smooth or symm
        Inkscape::NodePath::Node *othernode = other->other;
-        len = NR::L2(me->pos - node->pos);
-        delta = node->pos - othernode->pos;
-        linelen = NR::L2(delta);
+        double len = NR::L2(me->pos - node->pos);
+        NR::Point delta = node->pos - othernode->pos;
+        double linelen = NR::L2(delta);
         if (linelen < 1e-18)
             return;
         me->pos = node->pos + (len / linelen)*delta;
@@ -3005,19 +3134,17 @@ static void sp_node_adjust_handle(Inkscape::NodePath::Node *node, gint which_adj
     }
 
     if (node->type == Inkscape::NodePath::NODE_SYMM) {
-
+        // symmetrize 
         me->pos = 2 * node->pos - other->pos;
         return;
+    } else {
+        // smoothify
+        double len = NR::L2(me->pos - node->pos);
+        NR::Point delta = other->pos - node->pos;
+        double otherlen = NR::L2(delta);
+        if (otherlen < 1e-18) return;
+        me->pos = node->pos - (len / otherlen) * delta;
     }
-
-    /* We are smooth */
-
-    len = NR::L2(me->pos - node->pos);
-    delta = other->pos - node->pos;
-    otherlen = NR::L2(delta);
-    if (otherlen < 1e-18) return;
-
-    me->pos = node->pos - (len / otherlen) * delta;
 }
 
 /**
@@ -3032,17 +3159,14 @@ static void sp_node_adjust_handles(Inkscape::NodePath::Node *node)
     /* we are either smooth or symm */
 
     if (node->p.other == NULL) return;
-
     if (node->n.other == NULL) return;
 
-    if (node->code == NR_LINETO) {
-        if (node->n.other->code == NR_LINETO) return;
+    if (sp_node_side_is_line(node, &node->p)) {
         sp_node_adjust_handle(node, 1);
         return;
     }
 
-    if (node->n.other->code == NR_LINETO) {
-        if (node->code == NR_LINETO) return;
+    if (sp_node_side_is_line(node, &node->n)) {
         sp_node_adjust_handle(node, -1);
         return;
     }
@@ -3288,11 +3412,11 @@ node_request(SPKnot */*knot*/, NR::Point *p, guint state, gpointer data)
     NR::Point c;
     NR::Point pr;
 
-   Inkscape::NodePath::Node *n = (Inkscape::NodePath::Node *) data;
+    Inkscape::NodePath::Node *n = (Inkscape::NodePath::Node *) data;
 
     n->subpath->nodepath->desktop->snapindicator->remove_snappoint();
 
-   // If either (Shift and some handle retracted), or (we're already dragging out a handle)
+    // If either (Shift and some handle retracted), or (we're already dragging out a handle)
     if ( (!n->subpath->nodepath->straight_path) &&
          ( ((state & GDK_SHIFT_MASK) && ((n->n.other && n->n.pos == n->pos) || (n->p.other && n->p.pos == n->pos)))
            || n->dragging_out ) )
@@ -3436,14 +3560,23 @@ node_request(SPKnot */*knot*/, NR::Point *p, guint state, gpointer data)
             // move the node to the closest point
             sp_nodepath_selected_nodes_move(n->subpath->nodepath,
                                             n->origin[NR::X] + c[NR::X] - n->pos[NR::X],
-                                            n->origin[NR::Y] + c[NR::Y] - n->pos[NR::Y]);
+                                            n->origin[NR::Y] + c[NR::Y] - n->pos[NR::Y], 
+                                            true);
 
         } else {  // constraining to hor/vert
 
             if (fabs((*p)[NR::X] - n->origin[NR::X]) > fabs((*p)[NR::Y] - n->origin[NR::Y])) { // snap to hor
-                sp_nodepath_selected_nodes_move(n->subpath->nodepath, (*p)[NR::X] - n->pos[NR::X], n->origin[NR::Y] - n->pos[NR::Y]);
+                sp_nodepath_selected_nodes_move(n->subpath->nodepath,
+                                                (*p)[NR::X] - n->pos[NR::X], 
+                                                n->origin[NR::Y] - n->pos[NR::Y],
+                                                true, 
+                                                true, Inkscape::Snapper::ConstraintLine(component_vectors[NR::X]));
             } else { // snap to vert
-                sp_nodepath_selected_nodes_move(n->subpath->nodepath, n->origin[NR::X] - n->pos[NR::X], (*p)[NR::Y] - n->pos[NR::Y]);
+                sp_nodepath_selected_nodes_move(n->subpath->nodepath,
+                                                n->origin[NR::X] - n->pos[NR::X],
+                                                (*p)[NR::Y] - n->pos[NR::Y],
+                                                true,
+                                                true, Inkscape::Snapper::ConstraintLine(component_vectors[NR::Y]));
             }
         }
     } else { // move freely
@@ -3554,30 +3687,34 @@ static gboolean node_handle_request(SPKnot *knot, NR::Point *p, guint /*state*/,
         g_assert_not_reached();
     }
 
-    NRPathcode const othercode = sp_node_path_code_from_side(n, opposite);
-
-    SnapManager const &m = n->subpath->nodepath->desktop->namedview->snap_manager;
+    SPDesktop *desktop = n->subpath->nodepath->desktop;
+    SnapManager &m = desktop->namedview->snap_manager;
+    m.setup(desktop, n->subpath->nodepath->item);
     Inkscape::SnappedPoint s ;
-    if (opposite->other && (n->type != Inkscape::NodePath::NODE_CUSP) && (othercode == NR_LINETO)) {
-        /* We are smooth node adjacent with line */
-        NR::Point const delta = *p - n->pos;
-        NR::Coord const len = NR::L2(delta);
-        Inkscape::NodePath::Node *othernode = opposite->other;
-        NR::Point const ndelta = n->pos - othernode->pos;
-        NR::Coord const linelen = NR::L2(ndelta);
-        if (len > NR_EPSILON && linelen > NR_EPSILON) {
-            NR::Coord const scal = dot(delta, ndelta) / linelen;
-            (*p) = n->pos + (scal / linelen) * ndelta;
+
+    Inkscape::NodePath::Node *othernode = opposite->other;
+    if (othernode) {
+        if ((n->type != Inkscape::NodePath::NODE_CUSP) && sp_node_side_is_line(n, opposite)) {
+            /* We are smooth node adjacent with line */
+            NR::Point const delta = *p - n->pos;
+            NR::Coord const len = NR::L2(delta);
+            Inkscape::NodePath::Node *othernode = opposite->other;
+            NR::Point const ndelta = n->pos - othernode->pos;
+            NR::Coord const linelen = NR::L2(ndelta);
+            if (len > NR_EPSILON && linelen > NR_EPSILON) {
+                NR::Coord const scal = dot(delta, ndelta) / linelen;
+                (*p) = n->pos + (scal / linelen) * ndelta;
+            }
+            s = m.constrainedSnap(Inkscape::Snapper::SNAPPOINT_NODE, *p, Inkscape::Snapper::ConstraintLine(*p, ndelta));
+        } else {
+            s = m.freeSnap(Inkscape::Snapper::SNAPPOINT_NODE, *p);
         }
-        s = m.constrainedSnap(Inkscape::Snapper::SNAPPOINT_NODE, *p, Inkscape::Snapper::ConstraintLine(*p, ndelta), n->subpath->nodepath->item);
     } else {
-        s = m.freeSnap(Inkscape::Snapper::SNAPPOINT_NODE, *p, n->subpath->nodepath->item);
-    }
-    *p = s.getPoint();
-    if (s.getDistance() < NR_HUGE) {
-        n->subpath->nodepath->desktop->snapindicator->set_new_snappoint((*p).to_2geom());
+        s = m.freeSnap(Inkscape::Snapper::SNAPPOINT_NODE, *p);
     }
-
+    
+    s.getPoint(*p);
+    
     sp_node_adjust_handle(n, -which);
 
     return FALSE;
@@ -3613,21 +3750,42 @@ static void node_handle_moved(SPKnot *knot, NR::Point *p, guint state, gpointer
         int const snaps = prefs_get_int_attribute("options.rotationsnapsperpi", "value", 12);
         /* 0 interpreted as "no snapping". */
 
-        // The closest PI/snaps angle, starting from zero.
-        double const a_snapped = floor(rnew.a/(M_PI/snaps) + 0.5) * (M_PI/snaps);
-        if (me->origin_radial.a == HUGE_VAL) {
-            // ortho doesn't exist: original handle was zero length.
-            rnew.a = a_snapped;
-        } else {
-            /* The closest PI/2 angle, starting from original angle (i.e. snapping to original,
-             * its opposite and perpendiculars). */
+        // 1. Snap to the closest PI/snaps angle, starting from zero.
+        double a_snapped = floor(rnew.a/(M_PI/snaps) + 0.5) * (M_PI/snaps);
+
+        // 2. Snap to the original angle, its opposite and perpendiculars
+        if (me->origin_radial.a != HUGE_VAL) { // otherwise ortho doesn't exist: original handle was zero length
+            /* The closest PI/2 angle, starting from original angle */
             double const a_ortho = me->origin_radial.a + floor((rnew.a - me->origin_radial.a)/(M_PI/2) + 0.5) * (M_PI/2);
 
             // Snap to the closest.
-            rnew.a = ( fabs(a_snapped - rnew.a) < fabs(a_ortho - rnew.a)
+            a_snapped = ( fabs(a_snapped - rnew.a) < fabs(a_ortho - rnew.a)
                        ? a_snapped
                        : a_ortho );
         }
+
+        // 3. Snap to the angle of the opposite line, if any
+        Inkscape::NodePath::Node *othernode = other->other;
+        if (othernode) {
+            NR::Point other_to_snap(0,0);
+            if (sp_node_side_is_line(n, other)) {
+                other_to_snap = othernode->pos - n->pos;
+            } else {
+                other_to_snap = other->pos - n->pos;
+            }
+            if (NR::L2(other_to_snap) > 1e-3) {
+                Radial rother_to_snap(other_to_snap);
+                /* The closest PI/2 angle, starting from the angle of the opposite line segment */
+                double const a_oppo = rother_to_snap.a + floor((rnew.a - rother_to_snap.a)/(M_PI/2) + 0.5) * (M_PI/2);
+
+                // Snap to the closest.
+                a_snapped = ( fabs(a_snapped - rnew.a) < fabs(a_oppo - rnew.a)
+                       ? a_snapped
+                       : a_oppo );
+            }
+        }
+
+        rnew.a = a_snapped;
     }
 
     if (state & GDK_MOD1_MASK) {
@@ -3671,7 +3829,7 @@ static void node_handle_moved(SPKnot *knot, NR::Point *p, guint state, gpointer
 
     GString *length = SP_PX_TO_METRIC_STRING(rnew.r, desktop->namedview->getDefaultMetric());
 
-    mc->setF(Inkscape::NORMAL_MESSAGE,
+    mc->setF(Inkscape::IMMEDIATE_MESSAGE,
          _("<b>Node handle</b>: angle %0.2f&#176;, length %s; with <b>Ctrl</b> to snap angle; with <b>Alt</b> to lock length; with <b>Shift</b> to rotate both handles"), degrees, length->str);
 
     g_string_free(length, TRUE);
@@ -4544,16 +4702,14 @@ SPCurve* sp_nodepath_object_get_curve(SPObject *object, const gchar *key) {
     SPCurve *curve = NULL;
     if (SP_IS_PATH(object)) {
         SPCurve *curve_new = sp_path_get_curve_for_edit(SP_PATH(object));
-        curve = sp_curve_copy(curve_new);
+        curve = curve_new->copy();
     } else if ( IS_LIVEPATHEFFECT(object) && key) {
         const gchar *svgd = object->repr->attribute(key);
         if (svgd) {
-            NArtBpath *bpath = sp_svg_read_path(svgd);
-            SPCurve *curve_new = sp_curve_new_from_bpath(bpath);
+            Geom::PathVector pv = sp_svg_read_pathv(svgd);
+            SPCurve *curve_new = new SPCurve(pv);
             if (curve_new) {
                 curve = curve_new; // don't do curve_copy because curve_new is already only created for us!
-            } else {
-                g_free(bpath);
             }
         }
     }
@@ -4574,7 +4730,7 @@ void sp_nodepath_set_curve (Inkscape::NodePath::Path *np, SPCurve *curve) {
     } else if ( IS_LIVEPATHEFFECT(np->object) ) {
         // FIXME: this writing to string and then reading from string is bound to be slow.
         // create a method to convert from curve directly to 2geom...
-        gchar *svgpath = sp_svg_write_path(SP_CURVE_BPATH(np->curve));
+        gchar *svgpath = sp_svg_write_path( np->curve->get_pathvector() );
         LIVEPATHEFFECT(np->object)->lpe->setParameter(np->repr_key, svgpath);
         g_free(svgpath);
 
@@ -4582,21 +4738,43 @@ void sp_nodepath_set_curve (Inkscape::NodePath::Path *np, SPCurve *curve) {
     }
 }
 
+SPCanvasItem *
+sp_nodepath_generate_helperpath(SPDesktop *desktop, SPCurve *curve, const SPItem *item, guint32 color = 0xff0000ff) {
+    SPCurve *flash_curve = curve->copy();
+    Geom::Matrix i2d = item ? sp_item_i2d_affine(item) : Geom::identity();
+    flash_curve->transform(i2d);
+    SPCanvasItem * canvasitem = sp_canvas_bpath_new(sp_desktop_tempgroup(desktop), flash_curve);
+    // would be nice if its color could be XORed or something, now it is invisible for red stroked objects...
+    // unless we also flash the nodes...
+    sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(canvasitem), color, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
+    sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(canvasitem), 0, SP_WIND_RULE_NONZERO);
+    sp_canvas_item_show(canvasitem);
+    flash_curve->unref();
+    return canvasitem;
+}
+
+SPCanvasItem *
+sp_nodepath_generate_helperpath(SPDesktop *desktop, SPPath *path) {
+    return sp_nodepath_generate_helperpath(desktop, sp_path_get_curve_for_edit(path), SP_ITEM(path),
+                                           prefs_get_int_attribute("tools.nodes", "highlight_color", 0xff0000ff));
+}
+
 void sp_nodepath_show_helperpath(Inkscape::NodePath::Path *np, bool show) {
     np->show_helperpath = show;
 
     if (show) {
-        SPCurve *helper_curve = sp_curve_copy(np->curve);
-        sp_curve_transform(helper_curve, np->i2d );
+        SPCurve *helper_curve = np->curve->copy();
+        helper_curve->transform(np->i2d );
         if (!np->helper_path) {
             np->helper_path = sp_canvas_bpath_new(sp_desktop_controls(np->desktop), helper_curve);
             sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(np->helper_path), np->helperpath_rgba, np->helperpath_width, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
             sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(np->helper_path), 0, SP_WIND_RULE_NONZERO);
+            sp_canvas_item_move_to_z(np->helper_path, 0);
             sp_canvas_item_show(np->helper_path);
         } else {
             sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(np->helper_path), helper_curve);
         }
-        sp_curve_unref(helper_curve);
+        helper_curve->unref();
     } else {
         if (np->helper_path) {
             GtkObject *temp = np->helper_path;
@@ -4606,13 +4784,17 @@ void sp_nodepath_show_helperpath(Inkscape::NodePath::Path *np, bool show) {
     }
 }
 
-/* this function does not work yet */
+/* sp_nodepath_make_straight_path:
+ *   Prevents user from curving the path by dragging a segment or activating handles etc.
+ *   The resulting path is a linear interpolation between nodal points, with only straight segments.
+ * !!! this function does not work completely yet: it does not actively straighten the path, only prevents the path from being curved
+ */
 void sp_nodepath_make_straight_path(Inkscape::NodePath::Path *np) {
     np->straight_path = true;
     np->show_handles = false;
     g_message("add code to make the path straight.");
     // do sp_nodepath_convert_node_type on all nodes?
-    // search for this text !!!   "Make selected segments lines"
+    // coding tip: search for this text : "Make selected segments lines"
 }