Changeset 389 in josm for trunk/src

Timestamp:

2007-10-15T01:34:39+02:00 (18 years ago)

Author:

framm

Message:

• when new node inserted in exactly two segments at the same time, adjust node position to intersection if within 10px of click.

File:

• trunk/src/org/openstreetmap/josm/actions/mapmode/DrawAction.java (modified) (3 diffs)

trunk/src/org/openstreetmap/josm/actions/mapmode/DrawAction.java

@@ -13 +13 @@
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Iterator;
 import java.util.Map;
 import java.util.Set;
@@ -224 +225 @@
         }
 
+        /*
+         * Adjusts the position of a node to lie on a segment (or a segment
+         * intersection).
+         * 
+         * If one or more than two segments are passed, the node is adjusted
+         * to lie on the first segment that is passed.
+         * 
+         * If two segments are passed, the node is adjusted to be at their
+         * intersection.
+         * 
+         * No action is taken if no segments are passed.
+         * 
+         * @param segs the segments to use as a reference when adjusting
+         * @param n the node to adjust
+         */
         private static void adjustNode(Collection<NodePair> segs, Node n) {
-                // FIXME: find intersection if more than one seg.
-                if (segs.size() >= 1) {
-                        EastNorth P = n.eastNorth;
-                        NodePair seg = segs.iterator().next();
+                
+                switch (segs.size()) {
+                case 0:
+                        return;
+                case 2:
+                        // algorithm used here is a bit clumsy, anyone's welcome to replace
+                        // it by something else. All it does it compute the intersection between
+                        // the two segments and adjust the node position. The code doesnt 
+                        Iterator<NodePair> i = segs.iterator();
+                        NodePair seg = i.next();
                         EastNorth A = seg.a.eastNorth;
                         EastNorth B = seg.b.eastNorth;
+                        seg = i.next();
+                        EastNorth C = seg.a.eastNorth;
+                        EastNorth D = seg.b.eastNorth;
+
+                        EastNorth intersection = new EastNorth(
+                                det(det(A.east(), A.north(), B.east(), B.north()), A.east() - B.east(),
+                                        det(C.east(), C.north(), D.east(), D.north()), C.east() - D.east())/
+                                        det(A.east() - B.east(), A.north() - B.north(), C.east() - D.east(), C.north() - D.north()),
+                                det(det(A.east(), A.north(), B.east(), B.north()), A.north() - B.north(),
+                                        det(C.east(), C.north(), D.east(), D.north()), C.north() - D.north())/
+                                        det(A.east() - B.east(), A.north() - B.north(), C.east() - D.east(), C.north() - D.north())
+                        );
+                        
+                        // only adjust to intersection if within 10 pixel of mouse click; otherwise
+                        // fall through to default action.
+                        // (for semi-parallel lines, intersection might be miles away!)
+                        if (Main.map.mapView.getPoint(n.eastNorth).distance(Main.map.mapView.getPoint(intersection)) < 10) {
+                                n.eastNorth = intersection;
+                                return;
+                        }
+                
+                default:
+                        EastNorth P = n.eastNorth;
+                        seg = segs.iterator().next();
+                        A = seg.a.eastNorth;
+                        B = seg.b.eastNorth;
                         double a = P.distance(B);
                         double b = P.distance(A);
@@ -241 +289 @@
         }
         
+        // helper for adjustNode
+        static double det(double a, double b, double c, double d)
+        {
+                return a * d - b * c;
+        }
+
+        
         @Override public String getModeHelpText() {
                 return "Click to add a new node. Ctrl: no node re-use/auto-insert. Shift: no auto-connect. Alt: new way";