[PATCH] Ties

[Mark Hindley]

Hi all,

One of the bits of lily's output I have been least happy with is the
ties. When they are small they don't actually point at the notes they
tie.

I have revised tie.cc with a simpler control mechanism based on a
scheme property. IMHO the ties look much better. What do people think?

Best wishes

Mark


--- ./lily/tie.cc       Fri Apr  6 08:15:15 2001
+++ ./lily/tie.cc       Tue Jun 12 09:52:52 2001
@@ -185,28 +185,16 @@
 
   Bezier b  = slur_shape (width, h_inf, r_0);
   
-  Offset leave_dir = b.control_[1] - b.control_[0];
-
-  Grob *hed =head (me, headdir);
-  Real dx = (hed->extent (hed, X_AXIS).length () + x_gap_f)/2.0;
-  Real max_gap = leave_dir[Y_AXIS] * dx / leave_dir[X_AXIS];
-
   /*
-    for small ties (t small) we want to start in the Y-center (so dy = 0), for
-    large ties, the tie should appear to come from the center of the
-    head, so dy = max_gap
-
-    maybe use a different formula?
+    I think this better, particularly for small ties. It always allows the 
user to move ties if
+    they seem in the wrong place
 
     TODO: what if 2 heads have different size.
 
-    TODO: for small ties, it is better to start over the heads
-    iso. next to the heads. 
   */
-  Real t = (width / staff_space - 5.0);        // ugh.
-  Real dy = t > 0 ? max_gap * sqr (t / (1 + t)) : 0.0;
 
-  Real ypos = Tie::position_f (me) * staff_space/2 + dir * dy;
+  Real ypos = Tie::position_f (me) * staff_space/2
+    + dir * gh_scm2double (me->get_grob_property ("y-offset"));;
 
   /*
     Make sure we don't start on a dots

--- ./scm/grob-property-description.scm Thu May 10 07:44:42 2001
+++ ./scm/grob-property-description.scm Tue Jun 12 09:39:05 2001
@@ -362,4 +362,5 @@
 (grob-property-description 'word-space number? "elongate left by this much 
(FIXME: cumbersome semantics).")
 (grob-property-description 'x-gap number? "horizontal gap between notehead and 
tie.")
 (grob-property-description 'y-free number? "minimal vertical gap between slur 
and noteheads or stems.")
+(grob-property-description 'y-offset number? "extra vertical offset for ties 
away from the center line.")
 (grob-property-description 'y number? "set by beam: position of left edge.")

--- ./scm/grob-description.scm  Tue May 29 08:06:16 2001
+++ ./scm/grob-description.scm  Tue Jun 12 09:27:08 2001
@@ -673,6 +673,7 @@
                (details . ((ratio . 0.333) (height-limit . 1.0)))
                (thickness . 1.2)
                (x-gap . 0.2)
+               (y-offset . 0.6)
                (minimum-length  . 2.5)
                (meta . ,(grob-description "Tie" tie-interface ))
        ))