From: Mike Solomon <mike@apollinemike.com>
Date: Tue, 19 Jul 2011 13:59:37 +0000 (+0200)
Subject: Adds stem-begin-position callback.
X-Git-Tag: release/2.15.6-1~3^2~4
X-Git-Url: https://git.donarmstrong.com/?a=commitdiff_plain;h=3e8b3eb5e3e2054fdaf5b8bc71b1222c7db5ebe5;p=lilypond.git

Adds stem-begin-position callback.
---

diff --git a/lily/include/stem.hh b/lily/include/stem.hh
index 27fe988b61..3388e34b59 100644
--- a/lily/include/stem.hh
+++ b/lily/include/stem.hh
@@ -61,6 +61,7 @@ public:
   DECLARE_SCHEME_CALLBACK (calc_direction, (SCM));
   DECLARE_SCHEME_CALLBACK (calc_beaming, (SCM));
   DECLARE_SCHEME_CALLBACK (calc_length, (SCM));
+  DECLARE_SCHEME_CALLBACK (calc_stem_begin_position, (SCM));
   DECLARE_SCHEME_CALLBACK (calc_stem_end_position, (SCM));
   DECLARE_SCHEME_CALLBACK (calc_stem_info, (SCM));
   DECLARE_SCHEME_CALLBACK (calc_positioning_done, (SCM));
diff --git a/lily/stem.cc b/lily/stem.cc
index 04bc410592..5b1a3d5041 100644
--- a/lily/stem.cc
+++ b/lily/stem.cc
@@ -733,6 +733,32 @@ Stem::thickness (Grob *me)
     * Staff_symbol_referencer::line_thickness (me);
 }
 
+MAKE_SCHEME_CALLBACK (Stem, calc_stem_begin_position, 1);
+SCM
+Stem::calc_stem_begin_position (SCM smob)
+{
+  Grob *me = unsmob_grob (smob);
+  Direction d = get_grob_direction (me);
+  Real half_space = Staff_symbol_referencer::staff_space (me) * 0.5;
+  Grob *lh
+    = to_boolean (me->get_property ("avoid-note-head"))
+    ? last_head (me)
+    : first_head (me);
+
+  Real pos = Staff_symbol_referencer::get_position (lh);
+
+  if (Grob *head = support_head (me))
+    {
+      Interval head_height = head->extent (head, Y_AXIS);
+      Real y_attach = Note_head::stem_attachment_coordinate (head, Y_AXIS);
+
+      y_attach = head_height.linear_combination (y_attach);
+      pos += d * y_attach / half_space;
+    }
+
+  return scm_from_double (pos);
+}
+
 MAKE_SCHEME_CALLBACK (Stem, print, 1);
 SCM
 Stem::print (SCM smob)
@@ -771,7 +797,7 @@ Stem::print (SCM smob)
   Real half_space = Staff_symbol_referencer::staff_space (me) * 0.5;
 
   if (lh)
-    y2 = Staff_symbol_referencer::get_position (lh);
+    y2 = robust_scm2double (me->get_property ("stem-begin-position"), 0.0);
   else if (stemlet)
     {
       Real beam_translation = Beam::get_beam_translation (beam);
@@ -786,18 +812,6 @@ Stem::print (SCM smob)
 
   Interval stem_y (min (y1, y2), max (y2, y1));
 
-  if (Grob *head = support_head (me))
-    {
-      /*
-	must not take ledgers into account.
-      */
-      Interval head_height = head->extent (head, Y_AXIS);
-      Real y_attach = Note_head::stem_attachment_coordinate (head, Y_AXIS);
-
-      y_attach = head_height.linear_combination (y_attach);
-      stem_y[Direction (-d)] += d * y_attach / half_space;
-    }
-
   // URG
   Real stem_width = thickness (me);
   Real blot
@@ -1110,6 +1124,7 @@ ADD_INTERFACE (Stem,
 	       "note-heads "
 	       "positioning-done "
 	       "rests "
+	       "stem-begin-position "
 	       "stem-end-position "
 	       "stem-info "
 	       "stemlet-length "
diff --git a/scm/define-grob-properties.scm b/scm/define-grob-properties.scm
index 5c2114338e..40732d0e9d 100644
--- a/scm/define-grob-properties.scm
+++ b/scm/define-grob-properties.scm
@@ -841,6 +841,8 @@ the @code{staff-staff-spacing} property of the staff's
 structure.")
      (stem-attachment ,number-pair? "An @code{(@var{x} . @var{y})}
 pair where the stem attaches to the notehead.")
+     (stem-begin-position ,number? "Where does the stem begin (the
+position of the support-head)?")
      (stem-end-position ,number? "Where does the stem end (the end is
 opposite to the support-head)?")
      ;;[TODO: doco]
diff --git a/scm/define-grobs.scm b/scm/define-grobs.scm
index 177ebafc84..393bc7c187 100644
--- a/scm/define-grobs.scm
+++ b/scm/define-grobs.scm
@@ -1916,6 +1916,7 @@
 	(length . ,ly:stem::calc-length)
 	(neutral-direction . ,DOWN)
 	(positioning-done . ,ly:stem::calc-positioning-done)
+	(stem-begin-position . ,ly:stem::calc-stem-begin-position)
 	(stem-end-position . ,ly:stem::calc-stem-end-position)
 	(stem-info . ,ly:stem::calc-stem-info)
 	(stencil . ,ly:stem::print)