Document bound-details (sub-)properties in line-spanner-cc for IR (issue 560670043 by address@hidden)

[thomasmorley65]

Reviewers: ,

Message:
Please review

Description:
Document bound-details (sub-)properties in line-spanner-cc for IR

Please review this at https://codereview.appspot.com/560670043/

Affected files (+44, -1 lines):
  M lily/line-spanner.cc


Index: lily/line-spanner.cc
diff --git a/lily/line-spanner.cc b/lily/line-spanner.cc
index  
a4b8343e739665efe752e56cc1f950d27739f6bc..04079d6416a1648a0b0c1170982e6188f0ffbab3  
100644
--- a/lily/line-spanner.cc
+++ b/lily/line-spanner.cc
@@ -382,7 +382,50 @@ Line_spanner::print (SCM smob)

 ADD_INTERFACE (Line_spanner,
                "Generic line drawn between two objects, e.g., for use with"
-               " glissandi.",
+               " glissandi.\n"
+               "\n"
+               "@code{bound-details} is a nested alist.  It's possible to"
+               " specify settings for the sub-properties: @code{left},"
+               " @code{left-broken}, @code{right} and  
@code{right-broken}.\n"
+               "\n"
+               "Values for the following keys may be set:\n"
+               "\n"
+               "@table @code\n"
+               "@item Y\n"
+               "Sets the Y-coordinate of the end point, in staff-spaces"
+               " offset from the staff center line.  By default, it is the"
+               " center of the bound object, so a glissando points to the"
+               " vertical center of the note head.\n"
+               "For horizontal spanners, such as text spanners and"
+               " trill spanners, it is hardcoded to 0.\n"
+               "@item attach-dir\n"
+               "Determines where the line starts and ends in the"
+               " X-direction, relative to the bound object.\n"
+               " So, a value of -1 (or LEFT) makes the line start/end at"
+               " the left side of the note head it is attached to.\n"
+               "@item X\n"
+               "This is the absolute X-coordinate of the end point."
+               " Usually computed on the fly.\n"
+               "@item stencil\n"
+               "Line spanners may have symbols at the beginning or end,  
which"
+               " is contained in this sub-property.  For internal use.\n"
+               "@item text\n"
+               "This is a markup that is evaluated to yield the stencil.\n"
+               "@item stencil-align-dir-y\n"
+               "\n"
+               "@item stencil-offset\n"
+               "Without setting one of these, the stencil is simply put at  
the"
+               " end-point, centered on the line, as defined by the X and"
+               " Y sub-properties.  Setting either stencil-align-dir-y or"
+               " stencil-offset will move the symbol at the edge  
vertically"
+                "relative to the end point of the line\n"
+               "@item arrow\n"
+               "Produces an arrowhead at the end-points of the line.\n"
+               "@item padding\n"
+               "Controls the space between the specified end point of the"
+               " line and the actual end.  Without padding, a glissando  
would"
+               " start and end in the center of each note head.\n"
+               "@end table\n",

                /* properties */
                "bound-details "