From 9551796a06445e9570d5481a73aff11f1d259568 Mon Sep 17 00:00:00 2001
From: Reinhold Kainhofer <reinhold@kainhofer.com>
Date: Tue, 28 Dec 2010 21:46:15 +0100
Subject: [PATCH] Use callback to retrieve OctavateEight break-visibility from
 clef

Do not explicitly assign break-visibility to the OctavateEight,
use a callback to retrieve from clef. For one, this allows the user
to override the clef's break-visibility and affect the OctavateEight
without an explicit setting for it. On the other hand, by overriding
the break-visibility from the callback to a custom value (e.g.
all-invisible), this makes it finally possible to hide 8 from
a treble_8 clef for a tenor piece altogether, while keeping
the correct pitch (for MIDI etc.).
---
 .../notation/changing-defaults.itely          |  9 +++---
 input/regression/clef-oct-visibility.ly       | 28 +++++++++++++++++++
 lily/clef-engraver.cc                         |  6 +---
 scm/define-grobs.scm                          |  2 +-
 scm/output-lib.scm                            |  4 +++
 5 files changed, 38 insertions(+), 11 deletions(-)
 create mode 100644 input/regression/clef-oct-visibility.ly

diff --git a/Documentation/notation/changing-defaults.itely b/Documentation/notation/changing-defaults.itely
index 7a294693fe..aaf17246d0 100644
--- a/Documentation/notation/changing-defaults.itely
+++ b/Documentation/notation/changing-defaults.itely
@@ -3047,11 +3047,10 @@ occur only at explicit @code{\bar} commands.
 @cindex clefs, visibility of octavation
 
 The small octavation symbol on octavated clefs is produced by the
-@code{OctavateEight} layout object.  Its visibility is controlled
-independently from that of the @code{Clef} object, so it is
-necessary to apply any required @code{break-visibility} overrides
-to both the @code{Clef} and the @code{OctavateEight} layout objects
-to fully suppress such clef symbols at the start of each line.
+@code{OctavateEight} layout object.  Its visibility is automatically
+inherited from the @code{Clef} object, so it is not necessary to apply
+any required @code{break-visibility} overrides to the @code{OctavateEight} 
+layout objects to suppress octavation symbols for invisible clefs.
 
 For explicit clef changes, the @code{explicitClefVisibility}
 property controls both the clef symbol and any octavation symbol
diff --git a/input/regression/clef-oct-visibility.ly b/input/regression/clef-oct-visibility.ly
new file mode 100644
index 0000000000..0f8d480b24
--- /dev/null
+++ b/input/regression/clef-oct-visibility.ly
@@ -0,0 +1,28 @@
+\version "2.13.45"
+
+\header {
+
+    texidoc = "Octavation signs may be added to clefs.  By default,
+their break-visibility is derived from the associated clef, but it may
+be overridden explicitly. The initial treble_8 clef should not have an
+8, while the treble_8 clef after the tenor clef should.
+These settings also need to apply to clefs on new lines."
+
+}
+\layout { ragged-right = ##t  }
+
+
+\relative c' {
+  \override Staff.OctavateEight #'break-visibility = #all-invisible
+
+  \clef "treble_8"
+  c2 c |
+  c c | \break
+  c \clef "tenor" c |
+  \revert Staff.OctavateEight #'break-visibility
+  \clef "treble_8"
+  c2 c |
+  c c | \break
+  c c
+}
+
diff --git a/lily/clef-engraver.cc b/lily/clef-engraver.cc
index 37151c2fbe..d17ee6a19b 100644
--- a/lily/clef-engraver.cc
+++ b/lily/clef-engraver.cc
@@ -186,11 +186,7 @@ Clef_engraver::stop_translation_timestep ()
 	vis = get_property ("explicitClefVisibility");
 
       if (vis)
-	{
-	  clef_->set_property ("break-visibility", vis);
-	  if (octavate_)
-	    octavate_->set_property ("break-visibility", vis);
-	}
+	clef_->set_property ("break-visibility", vis);
 
       clef_ = 0;
 
diff --git a/scm/define-grobs.scm b/scm/define-grobs.scm
index 0f66726b47..d47633d48d 100644
--- a/scm/define-grobs.scm
+++ b/scm/define-grobs.scm
@@ -1324,7 +1324,7 @@
 
     (OctavateEight
      . (
-	(break-visibility . ,begin-of-line-visible)
+	(break-visibility . ,inherit-x-parent-visibility)
 	(font-shape . italic)
 	(font-size . -4)
 	(self-alignment-X . ,CENTER)
diff --git a/scm/output-lib.scm b/scm/output-lib.scm
index 6c10913d38..292755e27e 100644
--- a/scm/output-lib.scm
+++ b/scm/output-lib.scm
@@ -234,6 +234,10 @@ and duration-log @var{log}."
 (define-public center-visible          #(#f #t #f))
 (define-public end-of-line-visible     #(#t #f #f))
 (define-public all-invisible           #(#f #f #f))
+(define-public (inherit-x-parent-visibility grob)
+  (let ((parent (ly:grob-parent grob X)))
+    (ly:grob-property parent 'break-visibility all-invisible)))
+
 
 (define-public spanbar-begin-of-line-invisible #(#t #f #f))
 
-- 
2.39.5