[dia] Bug 618359 - Autrouting adjustment for arrowheads

[Hans Breuer <hans src gnome org>]

commit 94dd79e3001e859e0e73824870720d4bde9cdddf
Author: Hans Breuer <hans breuer org>
Date:   Thu Jun 2 20:52:15 2011 +0200

    Bug 618359 - Autrouting adjustment for arrowheads
    
    Easy fix by reusing extra_spacing.(start|end)_trans, i.e. information
    already available to the autoroute functions by OrthConn*.

 lib/autoroute.c |   35 +++++++++++++++++++++++++++++++++++
 1 files changed, 35 insertions(+), 0 deletions(-)
---
diff --git a/lib/autoroute.c b/lib/autoroute.c
index 1715252..3048655 100644
--- a/lib/autoroute.c
+++ b/lib/autoroute.c
@@ -44,6 +44,7 @@ static real autoroute_layout_orthogonal(Point *to,
 static real autoroute_layout_opposite(Point *to, 
 					guint *num_points, Point **points);
 static Point autolayout_adjust_for_gap(Point *pos, int dir, ConnectionPoint *cp);
+static void autolayout_adjust_for_arrow(Point *pos, int dir, real adjust);
 static guint autolayout_normalize_points(guint startdir, guint enddir,
 					 Point start, Point end,
 					 Point *newend);
@@ -100,7 +101,9 @@ autoroute_layout_orthconn(OrthConn *conn,
 	Point startpoint, endpoint;
 	Point otherpoint;
 	startpoint = autolayout_adjust_for_gap(&frompos, startdir, startconn);
+	autolayout_adjust_for_arrow(&startpoint, startdir, conn->extra_spacing.start_trans);
 	endpoint = autolayout_adjust_for_gap(&topos, enddir, endconn);
+	autolayout_adjust_for_arrow(&endpoint, enddir, conn->extra_spacing.end_trans);
 	/*
 	printf("Startdir %d enddir %d orgstart %.2f, %.2f orgend %.2f, %.2f start %.2f, %.2f end %.2f, %.2f\n",
 	       startdir, enddir,
@@ -138,6 +141,11 @@ autoroute_layout_orthconn(OrthConn *conn,
 							this_layout, 
 							this_num_points);
 	    best_num_points = this_num_points;
+            /* revert adjusting start and end point */
+	    autolayout_adjust_for_arrow(&best_layout[0], startdir, 
+	                                -conn->extra_spacing.start_trans);
+	    autolayout_adjust_for_arrow(&best_layout[best_num_points-1], enddir, 
+	                                -conn->extra_spacing.end_trans);
 	  } else {
 	      g_free(this_layout);
 	  }
@@ -235,6 +243,33 @@ autolayout_adjust_for_gap(Point *pos, int dir, ConnectionPoint *cp)
   return calculate_object_edge(pos, &dir_other, object);
 }
 
+/**
+ * Adjust the original position to move away from a potential arrow
+ *
+ * We could do some similar by making MIN_DIST depend on the arrow size,
+ * but this one is much more easy, not touchun the autolayout algorithm at 
+ * all. Needs to be called twice - second time with negative adjust - to
+ * move the point back to where it was.
+ */
+static void 
+autolayout_adjust_for_arrow(Point *pos, int dir, real adjust)
+{
+  switch (dir) {
+  case DIR_NORTH:
+    pos->y -= adjust;
+    break;
+  case DIR_EAST:
+    pos->x += adjust;
+    break;
+  case DIR_SOUTH:
+    pos->y += adjust;
+    break;
+  case DIR_WEST:
+    pos->x -= adjust;
+    break;
+  }
+}
+
 /** Lay out autorouting where start and end lines are parallel pointing the
  * same direction.  This can either a simple up-right-down layout, or if the
  * to point is too close to origo, it will go up-right-down-left-down.