Snap to grid/guide lines perpendicularly

(bzr r10976)

11 files changed, 59 insertions, 1 deletions

diff --git a/src/display/canvas-axonomgrid.cpp b/src/display/canvas-axonomgrid.cpp
index 1c74e3d86..ab0592fc6 100644
--- a/src/display/canvas-axonomgrid.cpp
+++ b/src/display/canvas-axonomgrid.cpp
@@ -737,6 +737,12 @@ void CanvasAxonomGridSnapper::_addSnappedPoint(IntermSnapResults &isr, Geom::Poi
     isr.points.push_back(dummy);
 }
 
+void CanvasAxonomGridSnapper::_addSnappedLinePerpendicularly(IntermSnapResults &isr, Geom::Point const snapped_point, Geom::Coord const snapped_distance, SnapSourceType const &source, long source_num, bool constrained_snap) const
+{
+    SnappedPoint dummy = SnappedPoint(snapped_point, source, source_num, Inkscape::SNAPTARGET_GRID_PERPENDICULAR, snapped_distance, getSnapperTolerance(), getSnapperAlwaysSnap(), constrained_snap, true);
+    isr.points.push_back(dummy);
+}
+
 bool CanvasAxonomGridSnapper::ThisSnapperMightSnap() const
 {
     return _snap_enabled && _snapmanager->snapprefs.isTargetSnappable(Inkscape::SNAPTARGET_GRID);
diff --git a/src/display/canvas-axonomgrid.h b/src/display/canvas-axonomgrid.h
index 0a12d3743..ec42b5f83 100644
--- a/src/display/canvas-axonomgrid.h
+++ b/src/display/canvas-axonomgrid.h
@@ -74,6 +74,7 @@ private:
     LineList _getSnapLines(Geom::Point const &p) const;
     void _addSnappedLine(IntermSnapResults &isr, Geom::Point const snapped_point, Geom::Coord const snapped_distance, SnapSourceType const &source, long source_num, Geom::Point const normal_to_line, const Geom::Point point_on_line) const;
     void _addSnappedPoint(IntermSnapResults &isr, Geom::Point const snapped_point, Geom::Coord const snapped_distance, SnapSourceType const &source, long source_num, bool constrained_snap) const;
+    void _addSnappedLinePerpendicularly(IntermSnapResults &isr, Geom::Point const snapped_point, Geom::Coord const snapped_distance, SnapSourceType const &source, long source_num, bool constrained_snap) const;
 
     CanvasAxonomGrid *grid;
 };
diff --git a/src/display/canvas-grid.cpp b/src/display/canvas-grid.cpp
index 3517e5b47..ea406663c 100644
--- a/src/display/canvas-grid.cpp
+++ b/src/display/canvas-grid.cpp
@@ -1046,6 +1046,12 @@ void CanvasXYGridSnapper::_addSnappedPoint(IntermSnapResults &isr, Geom::Point c
     isr.points.push_back(dummy);
 }
 
+void CanvasXYGridSnapper::_addSnappedLinePerpendicularly(IntermSnapResults &isr, Geom::Point const snapped_point, Geom::Coord const snapped_distance, SnapSourceType const &source, long source_num, bool constrained_snap) const
+{
+    SnappedPoint dummy = SnappedPoint(snapped_point, source, source_num, Inkscape::SNAPTARGET_GRID_PERPENDICULAR, snapped_distance, getSnapperTolerance(), getSnapperAlwaysSnap(), constrained_snap, true);
+    isr.points.push_back(dummy);
+}
+
 /**
  *  \return true if this Snapper will snap at least one kind of point.
  */
diff --git a/src/display/canvas-grid.h b/src/display/canvas-grid.h
index f3b285be7..173c0c02b 100644
--- a/src/display/canvas-grid.h
+++ b/src/display/canvas-grid.h
@@ -167,6 +167,7 @@ private:
     LineList _getSnapLines(Geom::Point const &p) const;
     void _addSnappedLine(IntermSnapResults &isr, Geom::Point const snapped_point, Geom::Coord const snapped_distance,  SnapSourceType const &source, long source_num, Geom::Point const normal_to_line, const Geom::Point point_on_line) const;
     void _addSnappedPoint(IntermSnapResults &isr, Geom::Point const snapped_point, Geom::Coord const snapped_distance, SnapSourceType const &source, long source_num, bool constrained_snap) const;
+    void _addSnappedLinePerpendicularly(IntermSnapResults &isr, Geom::Point const snapped_point, Geom::Coord const snapped_distance, SnapSourceType const &source, long source_num, bool constrained_snap) const;
     CanvasXYGrid *grid;
 };
 
diff --git a/src/display/snap-indicator.cpp b/src/display/snap-indicator.cpp
index ee719847f..d5b8ce07f 100644
--- a/src/display/snap-indicator.cpp
+++ b/src/display/snap-indicator.cpp
@@ -79,6 +79,9 @@ SnapIndicator::set_new_snaptarget(Inkscape::SnappedPoint const &p, bool pre_snap
             case SNAPTARGET_GRID_INTERSECTION:
                 target_name = _("grid intersection");
                 break;
+            case SNAPTARGET_GRID_PERPENDICULAR:
+                target_name = _("grid line (perpendicular)");
+                break;
             case SNAPTARGET_GUIDE:
                 target_name = _("guide");
                 break;
@@ -88,6 +91,9 @@ SnapIndicator::set_new_snaptarget(Inkscape::SnappedPoint const &p, bool pre_snap
             case SNAPTARGET_GUIDE_ORIGIN:
                 target_name = _("guide origin");
                 break;
+            case SNAPTARGET_GUIDE_PERPENDICULAR:
+                target_name = _("guide (perpendicular)");
+                break;
             case SNAPTARGET_GRID_GUIDE_INTERSECTION:
                 target_name = _("grid-guide intersection");
                 break;
diff --git a/src/guide-snapper.cpp b/src/guide-snapper.cpp
index d6741b642..11636b0fc 100644
--- a/src/guide-snapper.cpp
+++ b/src/guide-snapper.cpp
@@ -79,6 +79,11 @@ void Inkscape::GuideSnapper::_addSnappedLinesOrigin(IntermSnapResults &isr, Geom
     isr.points.push_back(dummy);
 }
 
+void Inkscape::GuideSnapper::_addSnappedLinePerpendicularly(IntermSnapResults &isr, Geom::Point const snapped_point, Geom::Coord const snapped_distance, SnapSourceType const &source, long source_num, bool constrained_snap) const
+{
+    SnappedPoint dummy = SnappedPoint(snapped_point, source, source_num, Inkscape::SNAPTARGET_GUIDE_PERPENDICULAR, snapped_distance, getSnapperTolerance(), getSnapperAlwaysSnap(), constrained_snap, true);
+    isr.points.push_back(dummy);
+}
 
 void Inkscape::GuideSnapper::_addSnappedPoint(IntermSnapResults &isr, Geom::Point const snapped_point, Geom::Coord const snapped_distance, SnapSourceType const &source, long source_num, bool constrained_snap) const
 {
diff --git a/src/guide-snapper.h b/src/guide-snapper.h
index f51939c08..aa0c45320 100644
--- a/src/guide-snapper.h
+++ b/src/guide-snapper.h
@@ -34,6 +34,7 @@ private:
     LineList _getSnapLines(Geom::Point const &p) const;
     void _addSnappedLine(IntermSnapResults &isr, Geom::Point const snapped_point, Geom::Coord const snapped_distance,  SnapSourceType const &source, long source_num, Geom::Point const normal_to_line, Geom::Point const point_on_line) const;
     void _addSnappedLinesOrigin(IntermSnapResults &isr, Geom::Point const origin, Geom::Coord const snapped_distance, SnapSourceType const &source, long source_num, bool constrained_snap) const;
+    void _addSnappedLinePerpendicularly(IntermSnapResults &isr, Geom::Point const snapped_point, Geom::Coord const snapped_distance, SnapSourceType const &source, long source_num, bool constrained_snap) const;
     void _addSnappedPoint(IntermSnapResults &isr, Geom::Point const snapped_point, Geom::Coord const snapped_distance, SnapSourceType const &source, long source_num, bool constrained_snap) const;
 };
 
diff --git a/src/line-snapper.cpp b/src/line-snapper.cpp
index 3fb503354..c8f10fb29 100644
--- a/src/line-snapper.cpp
+++ b/src/line-snapper.cpp
@@ -5,7 +5,7 @@
  *   Diederik van Lierop <mail@diedenrezi.nl>
  *   And others...
  *
- * Copyright (C) 1999-2008 Authors
+ * Copyright (C) 1999-2012 Authors
  *
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
@@ -53,6 +53,33 @@ void Inkscape::LineSnapper::freeSnap(IntermSnapResults &isr,
                 // 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;
diff --git a/src/line-snapper.h b/src/line-snapper.h
index 578a426ce..e7995cdb6 100644
--- a/src/line-snapper.h
+++ b/src/line-snapper.h
@@ -55,6 +55,7 @@ private:
   // Will only be implemented for guide lines, because grid lines don't have an origin
   virtual void _addSnappedLinesOrigin(IntermSnapResults &isr, Geom::Point const origin, Geom::Coord const snapped_distance, SnapSourceType const &source, long source_num, bool constrained_snap) const;
 
+  virtual void _addSnappedLinePerpendicularly(IntermSnapResults &isr, Geom::Point const snapped_point, Geom::Coord const snapped_distance, SnapSourceType const &source, long source_num, bool constrained_snap) const = 0;
   virtual void _addSnappedPoint(IntermSnapResults &isr, Geom::Point const snapped_point, Geom::Coord const snapped_distance, SnapSourceType const &source, long source_num, bool constrained_snap) const = 0;
 };
 
diff --git a/src/snap-enums.h b/src/snap-enums.h
index 22f1b9cdc..c6ca97402 100644
--- a/src/snap-enums.h
+++ b/src/snap-enums.h
@@ -79,9 +79,11 @@ enum SnapTargetType {
     SNAPTARGET_DATUMS_CATEGORY = 64, // will be used as a flag and must therefore be a power of two
     SNAPTARGET_GRID,
     SNAPTARGET_GRID_INTERSECTION,
+    SNAPTARGET_GRID_PERPENDICULAR,
     SNAPTARGET_GUIDE,
     SNAPTARGET_GUIDE_INTERSECTION,
     SNAPTARGET_GUIDE_ORIGIN,
+    SNAPTARGET_GUIDE_PERPENDICULAR,
     SNAPTARGET_GRID_GUIDE_INTERSECTION,
     SNAPTARGET_PAGE_BORDER,
     SNAPTARGET_PAGE_CORNER,
diff --git a/src/snap-preferences.cpp b/src/snap-preferences.cpp
index 09924e3bc..79e47ca83 100644
--- a/src/snap-preferences.cpp
+++ b/src/snap-preferences.cpp
@@ -88,10 +88,12 @@ void Inkscape::SnapPreferences::_mapTargetToArrayIndex(Inkscape::SnapTargetType
             // Some snap targets don't have their own toggle. These targets are called "secondary targets". We will re-map
             // them to their cousin which does have a toggle, and which is called a "primary target"
             case SNAPTARGET_GRID_INTERSECTION:
+            case SNAPTARGET_GRID_PERPENDICULAR:
                 target = SNAPTARGET_GRID;
                 break;
             case SNAPTARGET_GUIDE_INTERSECTION:
             case SNAPTARGET_GUIDE_ORIGIN:
+            case SNAPTARGET_GUIDE_PERPENDICULAR:
                 target = SNAPTARGET_GUIDE;
                 break;
             case SNAPTARGET_PAGE_CORNER: