Re: Make tablature half-note stem-spacing adjustable. (issue 110960043 by address@hidden)

[markpolesky]

Reviewers: dak,

Message:
On 2014/07/09 07:02:48, dak wrote:

https://codereview.appspot.com/110960043/diff/1/scm/define-grob-properties.scm
> File scm/define-grob-properties.scm (right):


https://codereview.appspot.com/110960043/diff/1/scm/define-grob-properties.scm#newcode243
> scm/define-grob-properties.scm:243: stems of a half note in tablature
when using
> @code{\tabFullNotation},
> @code{\\tabFullNotation}

I always get confused with that.  Are there some places where
@code{\foo} is allowed and other places where it is not?


https://codereview.appspot.com/110960043/diff/1/scm/define-grob-properties.scm#newcode245
> scm/define-grob-properties.scm:245: of the default @code{Staff}
staff-space
> height.")
> Why @code{Staff} here? Is this specific to Staff contexts only?  That
would mean
> that this is not in @code{TabStaff} ?

Hm.  How to word this?  If 'double-stem-separation were set to 1, the
horizontal distance between the stems would be the same as the vertical
distance between two staff-lines in a *regular* staff (i.e. the default
Staff.StaffSymbol.staff-space = 1).  But TabStaff is not a regular
staff, since its staff-lines are further apart (i.e. the default
TabStaff.Symbol.staff-space = 1.5).  If you have a better way to convey
this, let me know.

Mark

Description:
This adds a new property to the Stem grob called 'double-stem-separation
(default=0.5), that allows users to adjust the space between the
double-stemmed half-notes in tablature:

\new TabStaff {
  \tabFullNotation
  c4 c2 c4
  \override Stem.double-stem-separation = 0.3
  c4 c2 c4
}

It also centers the stems on the fret number and adjusts the X-extent
accordingly.

On the tracker:
http://code.google.com/p/lilypond/issues/detail?id=3999

Please review this at https://codereview.appspot.com/110960043/

Affected files (+16, -2 lines):
  M lily/stem.cc
  M scm/define-grob-properties.scm
  M scm/define-grobs.scm
  M scm/tablature.scm


Index: lily/stem.cc
diff --git a/lily/stem.cc b/lily/stem.cc
index  
39a77a3858fea8ab3d6a7da92df1f26182830439..cc488e312570ede4a4cc6270ab46b110c0431dee  
100644
--- a/lily/stem.cc
+++ b/lily/stem.cc
@@ -1152,6 +1152,7 @@ ADD_INTERFACE (Stem,
                "default-direction "
                "details "
                "direction "
+               "double-stem-separation "
                "duration-log "
                "flag "
                "french-beaming "
Index: scm/define-grob-properties.scm
diff --git a/scm/define-grob-properties.scm b/scm/define-grob-properties.scm
index  
fbb9d679ac50bd06f5eda056093fe3612bfc7772..f5a673a9027816fcabd086ccc5c7c1ae69e04a7c  
100644
--- a/scm/define-grob-properties.scm
+++ b/scm/define-grob-properties.scm
@@ -239,6 +239,10 @@ elements closer together.")
      (dot-placement-list ,list? "List consisting of
 @code{(@var{description} @var{string-number} @var{fret-number}
 @var{finger-number})} entries used to define fret diagrams.")
+     (double-stem-separation ,number? "The distance between the two
+stems of a half note in tablature when using @code{\tabFullNotation},
+not counting the width of the stems themselves, expressed as a multiple
+of the default @code{Staff} staff-space height.")
      (duration-log ,integer? "The 2-log of the note head duration,
 i.e., @code{0} = whole note, @code{1} = half note, etc.")

Index: scm/define-grobs.scm
diff --git a/scm/define-grobs.scm b/scm/define-grobs.scm
index  
572f80f660da0c5edf008246b24ed1c0aa66dedc..84e1283028b221a71840525e0c5824b02ea74abd  
100644
--- a/scm/define-grobs.scm
+++ b/scm/define-grobs.scm
@@ -2114,6 +2114,7 @@
         ;; and the extreme minima as abolute minimum length.

         (direction . ,ly:stem::calc-direction)
+        (double-stem-separation . 0.5)
         (duration-log . ,stem::calc-duration-log)
         (length . ,(ly:make-unpure-pure-container ly:stem::calc-length  
ly:stem::pure-calc-length))
         (neutral-direction . ,DOWN)
Index: scm/tablature.scm
diff --git a/scm/tablature.scm b/scm/tablature.scm
index  
36b81106c1bcb0046b9f2a73f5b7f1aab842bacf..bb30664083460e223c2d124b32245c4f972ff9ef  
100644
--- a/scm/tablature.scm
+++ b/scm/tablature.scm
@@ -85,7 +85,11 @@
     ;; is the note a (dotted) half note?
     (if (= 1 (ly:grob-property grob 'duration-log))
         ;; yes -> return double stem width
-        (cons (car X-extent) (+ 0.5 (* 2 (cdr X-extent))))
+        (let* ((single-stem-width (- (cdr X-extent) (car X-extent)))
+               (separation (ly:grob-property grob 'double-stem-separation))
+               (double-stem-width (+ single-stem-width separation))
+               (half-width (/ double-stem-width 2)))
+          (cons (- half-width) half-width))
         ;; no -> return simple stem width
         X-extent)))

@@ -95,7 +99,11 @@
     ;; is the note a (dotted) half note?
     (if (= 1 (ly:grob-property grob 'duration-log))
         ;; yes -> draw double stem
-        (ly:stencil-combine-at-edge stem X RIGHT stem 0.5)
+        (let* ((separation (ly:grob-property grob 'double-stem-separation))
+               (half-separation (/ separation 2)))
+          (ly:stencil-add
+            (ly:stencil-translate-axis stem (- half-separation) X)
+            (ly:stencil-translate-axis stem half-separation X)))
         ;; no -> draw simple stem
         stem)))