1) Add checkboxes for perpendicular and tangential snapping to the document properties dialog (on the snap tab)

2) Newly created guides (dragged off the ruler) will take on the angle of the curve that's being snapped to (either perpendicularly or tangentialy, depending of the settings in the document properties dialog)

(bzr r10975)

1 files changed, 48 insertions, 19 deletions

diff --git a/src/desktop-events.cpp b/src/desktop-events.cpp
index 923b15a88..ec9dbcea3 100644
--- a/src/desktop-events.cpp
+++ b/src/desktop-events.cpp
@@ -50,6 +50,7 @@ using Inkscape::DocumentUndo;
 
 static void snoop_extended(GdkEvent* event, SPDesktop *desktop);
 static void init_extended();
+void sp_dt_ruler_snap_new_guide(SPDesktop *desktop, SPCanvasItem *guide, Geom::Point &event_dt, Geom::Point &normal);
 
 /* Root item handler */
 
@@ -149,16 +150,11 @@ static gint sp_dt_ruler_event(GtkWidget *widget, GdkEvent *event, SPDesktopWidge
                 Geom::Point event_dt(desktop->w2d(event_w));
 
                 if (!(event->motion.state & GDK_SHIFT_MASK)) {
-                    SnapManager &m = desktop->namedview->snap_manager;
-                    m.setup(desktop);
-                    // We only have a temporary guide which is not stored in our document yet.
-                    // Because the guide snapper only looks in the document for guides to snap to,
-                    // we don't have to worry about a guide snapping to itself here
-                    m.guideFreeSnap(event_dt, SP_DRAG_MOVE_ORIGIN, Geom::rot90(normal));
-                    m.unSetup();
+                    sp_dt_ruler_snap_new_guide(desktop, guide, event_dt, normal);
                 }
-
+                sp_guideline_set_normal(SP_GUIDELINE(guide), normal);
                 sp_guideline_set_position(SP_GUIDELINE(guide), event_dt);
+
                 desktop->set_coordinate_status(event_dt);
                 desktop->setPosition(event_dt);
             }
@@ -172,13 +168,7 @@ static gint sp_dt_ruler_event(GtkWidget *widget, GdkEvent *event, SPDesktopWidge
                 Geom::Point event_dt(desktop->w2d(event_w));
 
                 if (!(event->button.state & GDK_SHIFT_MASK)) {
-                    SnapManager &m = desktop->namedview->snap_manager;
-                    m.setup(desktop);
-                    // We only have a temporary guide which is not stored in our document yet.
-                    // Because the guide snapper only looks in the document for guides to snap to,
-                    // we don't have to worry about a guide snapping to itself here
-                    m.guideFreeSnap(event_dt, SP_DRAG_MOVE_ORIGIN, Geom::rot90(normal));
-                    m.unSetup();
+                    sp_dt_ruler_snap_new_guide(desktop, guide, event_dt, normal);
                 }
 
                 dragging = false;
@@ -305,8 +295,11 @@ gint sp_dt_guide_event(SPCanvasItem *item, GdkEvent *event, gpointer data)
                     }
                 } else if (!((drag_type == SP_DRAG_ROTATE) && (event->motion.state & GDK_CONTROL_MASK))) {
                     // cannot use shift here to disable snapping, because we already use it for rotating the guide
-                    Geom::Point origin = (drag_type == SP_DRAG_ROTATE) ? guide->point_on_line : Geom::rot90(guide->normal_to_line);
-                    m.guideFreeSnap(motion_dt, drag_type, origin);
+                    if (drag_type == SP_DRAG_ROTATE) {
+                        m.guideFreeSnap(motion_dt, guide->point_on_line, true, false);
+                    } else {
+                        m.guideFreeSnap(motion_dt, guide->normal_to_line, false, true);
+                    }
                 }
                 m.unSetup();
 
@@ -379,8 +372,11 @@ gint sp_dt_guide_event(SPCanvasItem *item, GdkEvent *event, gpointer data)
                         }
                     } else if (!((drag_type == SP_DRAG_ROTATE) && (event->motion.state & GDK_CONTROL_MASK))) {
                         // cannot use shift here to disable snapping, because we already use it for rotating the guide
-                        Geom::Point origin = (drag_type == SP_DRAG_ROTATE) ? guide->point_on_line : Geom::rot90(guide->normal_to_line);
-                        m.guideFreeSnap(event_dt, drag_type, origin);
+                        if (drag_type == SP_DRAG_ROTATE) {
+                            m.guideFreeSnap(event_dt, guide->point_on_line, true, false);
+                        } else {
+                            m.guideFreeSnap(event_dt, guide->normal_to_line, false, true);
+                        }
                     }
                     m.unSetup();
 
@@ -661,6 +657,39 @@ void snoop_extended(GdkEvent* event, SPDesktop *desktop)
 }
 
 
+void sp_dt_ruler_snap_new_guide(SPDesktop *desktop, SPCanvasItem *guide, Geom::Point &event_dt, Geom::Point &normal)
+{
+    SnapManager &m = desktop->namedview->snap_manager;
+    m.setup(desktop);
+    // We're dragging a brand new guide, just pulled of the rulers seconds ago. When snapping to a
+    // path this guide will change it slope to become either tangential or perpendicular to that path. It's
+    // therefore not useful to try tangential or perpendicular snapping, so this will be disabled temporarily
+    bool pref_perp = m.snapprefs.getSnapPerp();
+    bool pref_tang = m.snapprefs.getSnapTang();
+    m.snapprefs.setSnapPerp(false);
+    m.snapprefs.setSnapTang(false);
+    // We only have a temporary guide which is not stored in our document yet.
+    // Because the guide snapper only looks in the document for guides to snap to,
+    // we don't have to worry about a guide snapping to itself here
+    Geom::Point normal_orig = normal;
+    m.guideFreeSnap(event_dt, normal, false, false);
+    // After snapping, both event_dt and normal have been modified accordingly; we'll take the normal (of the
+    // curve we snapped to) to set the normal the guide. And rotate it by 90 deg. if needed
+    if (pref_perp) { // Perpendicular snapping to paths is requested by the user, so let's do that
+        if (normal != normal_orig) {
+            normal = Geom::rot90(normal);
+        }
+    }
+    if (!(pref_tang || pref_perp)) { // if we don't want to snap either perpendicularly or tangentially, then
+        normal = normal_orig; // we must restore the normal to it's original state
+    }
+    // Restore the preferences
+    m.snapprefs.setSnapPerp(pref_perp);
+    m.snapprefs.setSnapTang(pref_tang);
+    m.unSetup();
+}
+
+
 
 /*
   Local Variables: