X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=scm%2Ffret-diagrams.scm;h=6dda45292852bdc0937521eda8abb1286d343b91;hb=HEAD;hp=f2e7fb6db4d86275985a4617c806c770a41002c0;hpb=e18531db1f79fb685fbd16d6a2a67bf4b6c09915;p=lilypond.git

diff --git a/scm/fret-diagrams.scm b/scm/fret-diagrams.scm
index f2e7fb6db4..6dda452928 100644
--- a/scm/fret-diagrams.scm
+++ b/scm/fret-diagrams.scm
@@ -1,6 +1,6 @@
 ;;;; This file is part of LilyPond, the GNU music typesetter.
 ;;;;
-;;;; Copyright (C) 2004--2010 Carl D. Sorensen <c_sorensen@byu.edu>
+;;;; Copyright (C) 2004--2015 Carl D. Sorensen <c_sorensen@byu.edu>
 ;;;;
 ;;;; LilyPond is free software: you can redistribute it and/or modify
 ;;;; it under the terms of the GNU General Public License as published by
@@ -15,16 +15,13 @@
 ;;;; You should have received a copy of the GNU General Public License
 ;;;; along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
 
-;
-;  Utility functions
-;
-;
+;;  Utility functions
 
 (define (string-x-extent start-point end-point)
   "Return the x-extent of a string that goes from start-point
 to end-point."
   (let ((x1 (car start-point))
-         (x2 (car end-point)))
+        (x2 (car end-point)))
     (if (> x1 x2)
         (cons x2 x1)
         (cons x1 x2))))
@@ -33,7 +30,7 @@ to end-point."
   "Return the y-extent of a string that goes from start-point
 to end-point."
   (let ((y1 (cdr start-point))
-         (y2 (cdr end-point)))
+        (y2 (cdr end-point)))
     (if (> y1 y2)
         (cons y2 y1)
         (cons y1 y2))))
@@ -47,7 +44,15 @@ to end-point."
 
 (define (get-numeric-from-key keystring)
   "Get the numeric value from a key of the form k:val"
-  (string->number (substring keystring 2 (string-length keystring))))
+  (let* ((entry (substring keystring 2 (string-length keystring)))
+         (numeric-entry (string->number entry)))
+    ;; throw an error, if `entry' can't be transformed into a number
+    (if numeric-entry
+        numeric-entry
+        (ly:error
+          "Unhandled entry in fret-diagram \"~a\" in \"~a\""
+          entry
+          keystring))))
 
 (define (numerify mylist)
   "Convert string values to numeric or character"
@@ -64,18 +69,72 @@ to end-point."
   (* 6 (/ (log mag) (log 2))))
 
 (define (fret-count fret-range)
- "Calculate the fret count for the diagram given the range of frets in the diagram."
- (1+ (- (cdr fret-range) (car fret-range))))
+  "Calculate the fret count for the diagram given the range of frets in the diagram."
+  (1+ (- (cdr fret-range) (car fret-range))))
+
+(define (dot-has-color dot-settings)
+  "Return a color-name as symbol, if found in @var{dot-settings} otherwise @code{#f}"
+  (cond ((null? dot-settings)
+         #f)
+        ;; Don't bother the user with quote/unquote.
+        ;; We use the name-symbol for the color, looking up in 'x11-color-list'
+        ((member (car dot-settings) (map car x11-color-list))
+         (car dot-settings))
+        (else (dot-has-color (cdr dot-settings)))))
+
+(define (dot-is-inverted dot-settings)
+  "Return @code{'inverted}, if found in @var{dot-settings} otherwise @code{'()}"
+  (let ((inverted (member 'inverted dot-settings)))
+    (if inverted
+        (car inverted)
+        '())))
+
+(define (dot-is-parenthesized dot-settings)
+  "Return @code{'parenthesized}, if found in @var{dot-settings} otherwise @code{'()}"
+  (let ((parenthesized (member 'parenthesized dot-settings)))
+    (if parenthesized
+        (car parenthesized)
+        '())))
+
+;; If @code{'default-paren-color} is not set, the parenthesis will take their
+;; color from the dot.
+;; Setting @code{'default-paren-color} will result in taking the color from
+;; `what-color', see below.
+(define (default-paren-color dot-settings)
+  "Return @code{'default-paren-color}, if found in @var{dot-settings} otherwise @code{'()}"
+  (let ((default-color (member 'default-paren-color dot-settings)))
+    (if default-color
+        (car default-color)
+        '())))
 
 (define (subtract-base-fret base-fret dot-list)
   "Subtract @var{base-fret} from every fret in @var{dot-list}"
   (if (null? dot-list)
       '()
       (let ((this-list (car dot-list)))
-        (cons* (list (car this-list) (- (second this-list) base-fret)
-                     (if (null? (cddr this-list))
-                         '()
-                         (third this-list)))
+        (cons* (list
+                ;; string
+                  (car this-list)
+                ;; fret
+                  (- (second this-list) base-fret)
+                ;; finger-number or markup
+                  (if (and (not (null? (cddr this-list)))
+                           (or (markup? (caddr this-list))
+                               (number? (caddr this-list))))
+                      (third this-list)
+                      '())
+                ;; inverted
+                  (dot-is-inverted this-list)
+                ;; parenthesis
+                  (dot-is-parenthesized this-list)
+                ;; color modifiers
+                  ;; parenthesis
+                  (default-paren-color this-list)
+                  ;; dots
+                  (let ((colored (dot-has-color this-list)))
+                    (if colored
+                        colored
+                        '())))
                (subtract-base-fret base-fret (cdr dot-list))))))
 
 (define (drop-paren item-list)
@@ -100,7 +159,7 @@ to end-point."
 
 (define (merge-details key alist-list . default)
   "Return @code{alist-list} entries for @code{key}, in one combined alist.
-There can be two @code{alist-list} entries for a given key. The first
+There can be two @code{alist-list} entries for a given key.  The first
 comes from the override-markup function, the second comes
 from property settings during a regular override.
 This is necessary because some details can be set in one
@@ -120,57 +179,53 @@ found."
   (helper key alist-list
           (if (pair? default) (car default) #f)))
 
-;
-;  Conversions between fret/string coordinate system and x-y coordinate
-;  system.
-;
-;  Fret coordinates are measured down the fretboard from the nut,
-;   starting at 0.
-;
-; String coordinates are measured from the lowest string, starting at 0.
-;
-; The x-y origin is at the intersection of the nut and the lowest string.
-;
-; X coordinates are positive to the right.
-; Y coordinates are positive up.
-;
+;;  Conversions between fret/string coordinate system and x-y coordinate
+;;  system.
+;;
+;;  Fret coordinates are measured down the fretboard from the nut,
+;;   starting at 0.
+;;
+;; String coordinates are measured from the lowest string, starting at 0.
+;;
+;; The x-y origin is at the intersection of the nut and the lowest string.
+;;
+;; X coordinates are positive to the right.
+;; Y coordinates are positive up.
 
 (define (negate-extent extent)
   "Return the extent in an axis opposite to the axis of @code{extent}."
-   (cons (- (cdr extent)) (- (car extent))))
+  (cons (- (cdr extent)) (- (car extent))))
 
 (define (stencil-fretboard-extent stencil fretboard-axis orientation)
   "Return the extent of @code{stencil} in the @code{fretboard-axis}
 direction."
   (if (eq? fretboard-axis 'fret)
-  (cond ((eq? orientation 'landscape)
-         (ly:stencil-extent stencil X))
-        ((eq? orientation 'opposing-landscape)
-         (negate-extent (ly:stencil-extent stencil X)))
-        (else
-         (negate-extent (ly:stencil-extent stencil Y))))
-        ; else -- eq? fretboard-axis 'string
-  (cond ((eq? orientation 'landscape)
-         (ly:stencil-extent stencil Y))
-        ((eq? orientation 'opposing-landscape)
-         (negate-extent (ly:stencil-extent stencil Y)))
-        (else
-         (ly:stencil-extent stencil Y)))))
+      (cond ((eq? orientation 'landscape)
+             (ly:stencil-extent stencil X))
+            ((eq? orientation 'opposing-landscape)
+             (negate-extent (ly:stencil-extent stencil X)))
+            (else
+             (negate-extent (ly:stencil-extent stencil Y))))
+      ;; else -- eq? fretboard-axis 'string
+      (cond ((eq? orientation 'landscape)
+             (ly:stencil-extent stencil Y))
+            ((eq? orientation 'opposing-landscape)
+             (negate-extent (ly:stencil-extent stencil Y)))
+            (else
+             (ly:stencil-extent stencil Y)))))
 
 
 (define (stencil-fretboard-offset stencil fretboard-axis orientation)
- "Return a the stencil coordinates of the center of @code{stencil}
+  "Return a the stencil coordinates of the center of @code{stencil}
 in the @code{fretboard-axis} direction."
   (* 0.5 (interval-length
-           (stencil-fretboard-extent stencil fretboard-axis orientation))))
+          (stencil-fretboard-extent stencil fretboard-axis orientation))))
 
 
 (define (string-thickness string thickness-factor)
   (expt (1+ thickness-factor) (1- string)))
 
-;
-;  Functions that create stencils used in the fret diagram
-;
+;;  Functions that create stencils used in the fret diagram
 
 (define (sans-serif-stencil layout props mag text)
   "Create a stencil in sans-serif font based on @var{layout} and @var{props}
@@ -181,16 +236,11 @@ with magnification @var{mag} of the string @var{text}."
            (prepend-alist-chain 'font-family 'sans props))))
     (interpret-markup layout my-props text)))
 
-;;
-;;
 ;;  markup commands and associated functions
-;;
-;;
-;;
 
 (define (fret-parse-marking-list marking-list my-fret-count)
- "Parse a fret-diagram-verbose marking list into component sublists"
- (let* ((fret-range (cons 1 my-fret-count))
+  "Parse a fret-diagram-verbose marking list into component sublists"
+  (let* ((fret-range (cons 1 my-fret-count))
          (capo-fret 0)
          (barre-list '())
          (dot-list '())
@@ -203,9 +253,13 @@ with magnification @var{mag} of the string @var{text}."
              ((or (eq? my-code 'open)(eq? my-code 'mute))
               (set! xo-list (cons* my-item xo-list)))
              ((eq? my-code 'barre)
-              (set! barre-list (cons* (cdr my-item) barre-list)))
+              (if (every number? (cdr my-item))
+                  (set! barre-list (cons* (cdr my-item) barre-list))
+                  (ly:error
+                    "barre-indications should contain only numbers: ~a"
+                    (cdr my-item))))
              ((eq? my-code 'capo)
-               (set! capo-fret (cadr my-item)))
+              (set! capo-fret (cadr my-item)))
              ((eq? my-code 'place-fret)
               (set! dot-list (cons* (cdr my-item) dot-list))))
             (parse-item (cdr mylist)))))
@@ -219,13 +273,17 @@ with magnification @var{mag} of the string @var{text}."
               (if (> fretval maxfret) (set! maxfret fretval))
               (if (< fretval minfret) (set! minfret fretval))
               (updatemax (cdr fret-list)))))
-      (if (> maxfret my-fret-count)
+      ;; take frets of 'barre-settings into account
+      (if (not (null? barre-list))
+          (set! minfret (apply min minfret (map last barre-list))))
+      (if (or (> maxfret my-fret-count) (> capo-fret 1))
           (set! fret-range
                 (cons minfret
                       (let ((upfret (- (+ minfret my-fret-count) 1)))
                         (if (> maxfret upfret) maxfret upfret)))))
-      (set! capo-fret (1+ (- capo-fret minfret)))
-      ; subtract fret from dots
+      (if (not (zero? (apply min capo-fret (map cadr dot-list))))
+          (set! capo-fret (1+ (- capo-fret minfret))))
+      ;; subtract fret from dots
       (set! dot-list (subtract-base-fret (- (car fret-range) 1) dot-list)))
     (acons 'fret-range fret-range
            (acons 'barre-list barre-list
@@ -236,47 +294,51 @@ with magnification @var{mag} of the string @var{text}."
 (define (make-fret-diagram layout props marking-list)
   "Make a fret diagram markup"
   (let* (
-         ; note: here we get items from props that are needed in this routine,
-         ; or that are needed in more than one of the procedures
-         ; called from this routine.  If they're only used in one of the
-         ; sub-procedure, they're obtained in that procedure
+         ;; note: here we get items from props that are needed in this routine,
+         ;; or that are needed in more than one of the procedures
+         ;; called from this routine.  If they're only used in one of the
+         ;; sub-procedure, they're obtained in that procedure
          (size (chain-assoc-get 'size props 1.0)) ; needed for everything
-         ;TODO -- get string-count directly from length of stringTunings;
-         ;         from FretBoard engraver, but not from markup call
+         ;;TODO -- get string-count directly from length of stringTunings;
+         ;;         from FretBoard engraver, but not from markup call
          (details (merge-details 'fret-diagram-details props '()))
+         (fret-distance
+          (assoc-get 'fret-distance details 1.0))
+         (string-distance
+          (assoc-get 'string-distance details 1.0))
          (string-count
-           (assoc-get 'string-count details 6)) ; needed for everything
+          (assoc-get 'string-count details 6)) ;; needed for everything
          (my-fret-count
-           (assoc-get 'fret-count details 4)) ; needed for everything
+          (assoc-get 'fret-count details 4)) ;; needed for everything
          (orientation
-           (assoc-get 'orientation details 'normal)) ; needed for everything
+          (assoc-get 'orientation details 'normal)) ;; needed for everything
          (finger-code
-           (assoc-get
-             'finger-code details 'none)) ; needed for draw-dots and draw-barre
+          (assoc-get
+           'finger-code details 'none)) ;; needed for draw-dots and draw-barre
          (default-dot-radius
-           (if (eq? finger-code 'in-dot) 0.425 0.25)) ; bigger dots if labeled
+           (if (eq? finger-code 'in-dot) 0.425 0.25)) ;; bigger dots if labeled
          (default-dot-position
            (if (eq? finger-code 'in-dot)
                (- 0.95 default-dot-radius)
                0.6)) ; move up to make room for bigger dot if labeled
          (dot-radius
-           (assoc-get
-             'dot-radius details default-dot-radius))  ; needed for draw-dots
-                                                       ; and draw-barre
+          (assoc-get
+           'dot-radius details default-dot-radius))
+         ;; needed for draw-dots and draw-barre
          (dot-position
-           (assoc-get
-             'dot-position details default-dot-position)) ; needed for
-                                                    ; draw-dots and draw-barre
+          (assoc-get
+           'dot-position details default-dot-position))
+         ;; needed for draw-dots and draw-barre
          (th
-           (* (ly:output-def-lookup layout 'line-thickness)
-              (chain-assoc-get 'thickness props 0.5))) ; needed for draw-frets
-                                                       ; and draw-strings
+          (* (ly:output-def-lookup layout 'line-thickness)
+             (chain-assoc-get 'thickness props 0.5)))
+         ;; needed for draw-frets and draw-strings
          (sth (* size th))
          (thickness-factor (assoc-get 'string-thickness-factor details 0))
+         (paren-padding (assoc-get 'paren-padding details 0.05))
          (alignment
-           (chain-assoc-get 'align-dir props -0.4)) ; needed only here
-         (xo-padding
-           (* size (assoc-get 'xo-padding details 0.2))) ; needed only here
+          (chain-assoc-get 'align-dir props -0.4)) ;; needed only here
+         (xo-padding (assoc-get 'xo-padding details 0.2)) ;; needed only here
          (parameters (fret-parse-marking-list marking-list my-fret-count))
          (capo-fret (assoc-get 'capo-fret parameters 0))
          (dot-list (assoc-get 'dot-list parameters))
@@ -285,9 +347,9 @@ with magnification @var{mag} of the string @var{text}."
          (my-fret-count (fret-count fret-range))
          (barre-list (assoc-get 'barre-list parameters))
          (barre-type
-           (assoc-get 'barre-type details 'curved))
+          (assoc-get 'barre-type details 'curved))
          (fret-diagram-stencil '()))
-    ;
+
     ;;  Here are the fret diagram helper functions that depend on the
     ;;  fret diagram parameters.  The functions are here because the
     ;;  diagram parameters are part of the lexical scope here.
@@ -296,24 +358,24 @@ with magnification @var{mag} of the string @var{text}."
       "Return a pair @code{(x-coordinate . y-coordinate)}
       in stencil coordinate system."
       (cond
-        ((eq? orientation 'landscape)
-         (cons fret-coordinate
-               (- string-coordinate (1- string-count))))
-        ((eq? orientation 'opposing-landscape)
-         (cons (- fret-coordinate) (- string-coordinate)))
-        (else
-          (cons string-coordinate (- fret-coordinate)))))
+       ((eq? orientation 'landscape)
+        (cons fret-coordinate
+              (- string-coordinate (1- string-count))))
+       ((eq? orientation 'opposing-landscape)
+        (cons (- fret-coordinate) (- string-coordinate)))
+       (else
+        (cons string-coordinate (- fret-coordinate)))))
 
     (define (stencil-coordinate-offset fret-offset string-offset)
       "Return a pair @code{(x-offset . y-offset)}
       for translation in stencil coordinate system."
       (cond
-        ((eq? orientation 'landscape)
-         (cons fret-offset (- string-offset)))
-        ((eq? orientation 'opposing-landscape)
-         (cons (- fret-offset) string-offset))
-        (else
-          (cons string-offset (- fret-offset)))))
+       ((eq? orientation 'landscape)
+        (cons fret-offset (- string-offset)))
+       ((eq? orientation 'opposing-landscape)
+        (cons (- fret-offset) string-offset))
+       (else
+        (cons string-offset (- fret-offset)))))
 
 
 
@@ -323,56 +385,57 @@ with magnification @var{mag} of the string @var{text}."
 string coordinate @var{start} to string-coordinate @var{stop} with a
 baseline at fret coordinate @var{base}, a height of
 @var{height}, and a half thickness of @var{half-thickness}."
-     (let* ((width (+ (- stop start) 1))
-           (cp-left-width (+ (* width half-thickness) start))
-           (cp-right-width (- stop (* width half-thickness)))
-           (bottom-control-point-height
-             (- base (- height half-thickness)))
-           (top-control-point-height
-             (- base height))
-           (left-end-point
-             (stencil-coordinates base start))
-           (right-end-point
-             (stencil-coordinates base stop))
-           (left-upper-control-point
-             (stencil-coordinates
+      (let* ((width (+ (- stop start) 1))
+             (cp-left-width (+ (* width half-thickness) start))
+             (cp-right-width (- stop (* width half-thickness)))
+             (bottom-control-point-height
+              (- base (- height half-thickness)))
+             (top-control-point-height
+              (- base height))
+             (left-end-point
+              (stencil-coordinates base start))
+             (right-end-point
+              (stencil-coordinates base stop))
+             (left-upper-control-point
+              (stencil-coordinates
                top-control-point-height cp-left-width))
-           (left-lower-control-point
-             (stencil-coordinates
+             (left-lower-control-point
+              (stencil-coordinates
                bottom-control-point-height cp-left-width))
-           (right-upper-control-point
-             (stencil-coordinates
+             (right-upper-control-point
+              (stencil-coordinates
                top-control-point-height cp-right-width))
-           (right-lower-control-point
-             (stencil-coordinates
+             (right-lower-control-point
+              (stencil-coordinates
                bottom-control-point-height cp-right-width)))
-      ; order of bezier control points is:
-      ;    left cp low, right cp low, right end low, left end low
-      ;    right cp high, left cp high, left end high, right end high.
-      ;
-      (list left-lower-control-point
-            right-lower-control-point
-            right-end-point
-            left-end-point
-            right-upper-control-point
-            left-upper-control-point
-            left-end-point
-            right-end-point)))
+
+        ;; order of bezier control points is:
+        ;;   left cp low, left cp low, right cp low, right end low
+        ;;   right cp high, left cp high
+
+        (list
+              left-end-point
+              left-lower-control-point
+              right-lower-control-point
+              right-end-point
+
+              right-upper-control-point
+              left-upper-control-point)))
 
     (define (draw-strings)
       "Draw the string lines for a fret diagram with
 @var{string-count} strings and frets as indicated in @var{fret-range}.
 Line thickness is given by @var{th}, fret & string spacing by
-@var{size}.  Orientation is determined by @var{orientation}. "
+@var{size}.  Orientation is determined by @var{orientation}."
 
       (define (helper x)
         (if (null? (cdr x))
-          (string-stencil (car x))
-          (ly:stencil-add
             (string-stencil (car x))
-            (helper (cdr x)))))
+            (ly:stencil-add
+             (string-stencil (car x))
+             (helper (cdr x)))))
 
-      (let* ( (string-list (map 1+ (iota string-count))))
+      (let* ((string-list (map 1+ (iota string-count))))
         (helper string-list)))
 
     (define (string-stencil string)
@@ -380,17 +443,19 @@ Line thickness is given by @var{th}, fret & string spacing by
       overall parameters."
       (let* ((string-coordinate (- string-count string))
              (current-string-thickness
-               (* th size (string-thickness string thickness-factor)))
+              (* th size (string-thickness string thickness-factor)))
              (fret-half-thickness (* size th 0.5))
              (half-string (* current-string-thickness 0.5))
              (start-coordinates
-               (stencil-coordinates
-                 (- fret-half-thickness)
-                 (- (* size string-coordinate) half-string)))
+              (stencil-coordinates
+               (- fret-half-thickness)
+               (- (* size string-distance string-coordinate) half-string)))
              (end-coordinates
-               (stencil-coordinates
-                 (+ fret-half-thickness (* size (1+ (fret-count fret-range))))
-                 (+ half-string (* size string-coordinate)))))
+              (stencil-coordinates
+               (+ fret-half-thickness
+                  (* size fret-distance (1+ (fret-count fret-range))))
+               (+ half-string
+                  (* size string-distance string-coordinate)))))
         (ly:round-filled-box
          (string-x-extent start-coordinates end-coordinates)
          (string-y-extent start-coordinates end-coordinates)
@@ -400,457 +465,551 @@ Line thickness is given by @var{th}, fret & string spacing by
       "Draw the fret lines for a fret diagram with
 @var{string-count} strings and frets as indicated in @var{fret-range}.
 Line thickness is given by @var{th}, fret & string spacing by
-@var{size}. Orientation is given by @var{orientation}."
+@var{size}.  Orientation is given by @var{orientation}."
       (define (helper x)
         (if (null? (cdr x))
-          (fret-stencil (car x))
-          (ly:stencil-add
             (fret-stencil (car x))
-            (helper (cdr x)))))
+            (ly:stencil-add
+             (fret-stencil (car x))
+             (helper (cdr x)))))
 
       (let ((fret-list (iota (1+ my-fret-count))))
         (helper fret-list)))
 
-     (define (fret-stencil fret)
-        "Make a stencil for @code{fret}, given the
+    (define (fret-stencil fret)
+      "Make a stencil for @code{fret}, given the
 fret-diagram overall parameters."
-       (let* ((low-string-half-thickness
-                (* 0.5
-                   size
-                   th
-                   (string-thickness string-count thickness-factor)))
-              (fret-half-thickness (* 0.5 size th))
-              (start-coordinates
-                (stencil-coordinates
-                  (* size fret)
-                  (- fret-half-thickness low-string-half-thickness)))
-              (end-coordinates
-                (stencil-coordinates
-                  (* size fret)
-                  (* size (1- string-count)))))
-         (make-line-stencil
-           (* size th)
-           (car start-coordinates) (cdr start-coordinates)
-           (car end-coordinates) (cdr end-coordinates))))
-
-     (define (draw-barre barre-list)
-       "Create barre indications for a fret diagram"
-       (if (not (null? barre-list))
-         (let* ((string1 (caar barre-list))
-                (string2 (cadar barre-list))
-                (barre-fret (caddar barre-list))
-                (top-fret (cdr fret-range))
-                (low-fret (car fret-range))
-                (fret (1+ (- barre-fret low-fret)))
-                (barre-vertical-offset 0.5)
-                (dot-center-fret-coordinate (+ (1- fret) dot-position))
-                (barre-fret-coordinate
+      (let* ((low-string-half-thickness
+              (* 0.5
+                 size
+                 th
+                 (string-thickness string-count thickness-factor)))
+             (fret-half-thickness (* 0.5 size th))
+             (start-coordinates
+              (stencil-coordinates
+               (* fret-distance size fret)
+               (- fret-half-thickness low-string-half-thickness)))
+             (end-coordinates
+              (stencil-coordinates
+               (* fret-distance size fret)
+               (* size string-distance (1- string-count)))))
+        (make-line-stencil
+         (* size th)
+         (car start-coordinates) (cdr start-coordinates)
+         (car end-coordinates) (cdr end-coordinates))))
+
+    (define (draw-barre barre-list)
+      "Create barre indications for a fret diagram"
+      (if (not (null? barre-list))
+          (let* ((string1 (caar barre-list))
+                 (string2 (cadar barre-list))
+                 (barre-fret (caddar barre-list))
+                 (top-fret (cdr fret-range))
+                 (low-fret (car fret-range))
+                 (fret (1+ (- barre-fret low-fret)))
+                 (barre-vertical-offset 0.5)
+                 (dot-center-fret-coordinate (+ (1- fret) dot-position))
+                 (barre-fret-coordinate
                   (+ dot-center-fret-coordinate
                      (* (- barre-vertical-offset 0.5) dot-radius)))
-                (barre-start-string-coordinate (- string-count string1))
-                (barre-end-string-coordinate (- string-count string2))
-                (scale-dot-radius (* size dot-radius))
-                (barre-type (assoc-get 'barre-type details 'curved))
-                (barre-stencil
+                 (barre-start-string-coordinate (- string-count string1))
+                 (barre-end-string-coordinate (- string-count string2))
+                 (scale-dot-radius (* size dot-radius))
+                 (barre-type (assoc-get 'barre-type details 'curved))
+                 (barre-stencil
                   (cond
-                    ((eq? barre-type 'straight)
-                     (make-straight-barre-stencil
-                       barre-fret-coordinate
-                       barre-start-string-coordinate
-                       barre-end-string-coordinate
-                       scale-dot-radius))
-                    ((eq? barre-type 'curved)
-                     (make-curved-barre-stencil
-                       barre-fret-coordinate
-                       barre-start-string-coordinate
-                       barre-end-string-coordinate
-                       scale-dot-radius)))))
-           (if (not (null? (cdr barre-list)))
-             (ly:stencil-add
-               barre-stencil
-               (draw-barre (cdr barre-list)))
-             barre-stencil ))))
-
-     (define (make-straight-barre-stencil
-               fret-coordinate
-               start-string-coordinate
-               end-string-coordinate
-               half-thickness)
-       "Create a straight barre stencil."
-       (let ((start-point
-               (stencil-coordinates
-                 (* size fret-coordinate)
-                 (* size start-string-coordinate)))
-             (end-point
-               (stencil-coordinates
-                 (* size fret-coordinate)
-                 (* size end-string-coordinate))))
-         (make-line-stencil
-           half-thickness
-           (car start-point)
-           (cdr start-point)
-           (car end-point)
-           (cdr end-point))))
-
-     (define (make-curved-barre-stencil
-               fret-coordinate
-               start-string-coordinate
-               end-string-coordinate
-               half-thickness)
-       "Create a curved barre stencil."
-       (let* ((bezier-thick 0.1)
-              (bezier-height 0.5)
-              (bezier-list
-                (make-bezier-sandwich-list
-                  (* size start-string-coordinate)
-                  (* size end-string-coordinate)
-                  (* size fret-coordinate)
-                  (* size bezier-height)
-                  (* size bezier-thick)))
-              (box-lower-left
-                (stencil-coordinates
-                  (+ (* size fret-coordinate) half-thickness)
-                  (- (* size start-string-coordinate) half-thickness)))
-              (box-upper-right
-                (stencil-coordinates
-                  (- (* size fret-coordinate)
-                     (* size bezier-height)
-                     half-thickness)
-                  (+ (* size end-string-coordinate) half-thickness)))
-              (x-extent (cons (car box-lower-left) (car box-upper-right)))
-              (y-extent (cons (cdr box-lower-left) (cdr box-upper-right))))
-         (ly:make-stencil
-           (list 'bezier-sandwich
-                 `(quote ,bezier-list)
-                 (* size bezier-thick))
-           x-extent
-           y-extent)))
-
-     (define (draw-dots dot-list)
-       "Make dots for fret diagram."
-
-       (let* ( (scale-dot-radius (* size dot-radius))
+                   ((eq? barre-type 'straight)
+                    (make-straight-barre-stencil
+                     barre-fret-coordinate
+                     barre-start-string-coordinate
+                     barre-end-string-coordinate
+                     scale-dot-radius))
+                   ((eq? barre-type 'curved)
+                    (make-curved-barre-stencil
+                     barre-fret-coordinate
+                     barre-start-string-coordinate
+                     barre-end-string-coordinate
+                     scale-dot-radius)))))
+            (if (not (null? (cdr barre-list)))
+                (ly:stencil-add
+                 barre-stencil
+                 (draw-barre (cdr barre-list)))
+                barre-stencil ))))
+
+    (define (make-straight-barre-stencil
+             fret-coordinate
+             start-string-coordinate
+             end-string-coordinate
+             half-thickness)
+      "Create a straight barre stencil."
+      (let ((start-point
+             (stencil-coordinates
+              (* size fret-distance fret-coordinate)
+              (* size string-distance start-string-coordinate)))
+            (end-point
+             (stencil-coordinates
+              (* size fret-distance fret-coordinate)
+              (* size string-distance end-string-coordinate))))
+        (make-line-stencil
+         half-thickness
+         (car start-point)
+         (cdr start-point)
+         (car end-point)
+         (cdr end-point))))
+
+    (define (make-curved-barre-stencil
+             fret-coordinate
+             start-string-coordinate
+             end-string-coordinate
+             half-thickness)
+      "Create a curved barre stencil."
+      (let* ((bezier-thick 0.1)
+             (bezier-height 0.5)
+             (bezier-list
+              (make-bezier-sandwich-list
+               (* size string-distance start-string-coordinate)
+               (* size string-distance end-string-coordinate)
+               (* size fret-distance fret-coordinate)
+               (* size bezier-height)
+               (* size bezier-thick))))
+        (make-bezier-sandwich-stencil
+         bezier-list
+         (* size bezier-thick))))
+
+    (define (draw-dots dot-list)
+      "Make dots for fret diagram."
+
+      (let* ( (scale-dot-radius (* size dot-radius))
               (scale-dot-thick (* size th))
-              (dot-color (assoc-get 'dot-color details 'black))
+              (default-dot-color (assoc-get 'dot-color details))
               (finger-label-padding 0.3)
               (dot-label-font-mag
-                (* scale-dot-radius
-                   (assoc-get 'dot-label-font-mag details 1.0)))
+               (* scale-dot-radius
+                  (assoc-get 'dot-label-font-mag details 1.0)))
               (string-label-font-mag
-                (* size
-                   (assoc-get
-                     'string-label-font-mag details
-                     (cond ((or (eq? orientation 'landscape)
-                                (eq? orientation 'opposing-landscape))
-                            0.5)
-                           (else  0.6)))))
+               (* size
+                  (assoc-get
+                   'string-label-font-mag details
+                   (cond ((or (eq? orientation 'landscape)
+                              (eq? orientation 'opposing-landscape))
+                          0.5)
+                         (else  0.6)))))
               (mypair (car dot-list))
               (restlist (cdr dot-list))
               (string (car mypair))
               (fret (cadr mypair))
-              (fret-coordinate (* size (+ (1- fret) dot-position)))
-              (string-coordinate (* size (- string-count string)))
+              (fret-coordinate
+               (* size fret-distance (+ (1- fret) dot-position)))
+              (string-coordinate
+               (* size string-distance (- string-count string)))
               (dot-coordinates
-                (stencil-coordinates fret-coordinate string-coordinate))
+               (stencil-coordinates fret-coordinate string-coordinate))
               (extent (cons (- scale-dot-radius) scale-dot-radius))
               (finger (caddr mypair))
               (finger (if (number? finger) (number->string finger) finger))
-              (dot-stencil (if (eq? dot-color 'white)
-                             (ly:stencil-add
-                               (make-circle-stencil
-                                 scale-dot-radius scale-dot-thick #t)
-                               (ly:stencil-in-color
-                                 (make-circle-stencil
-                                   (- scale-dot-radius (* 0.5 scale-dot-thick))
-                                   0  #t)
-                                 1 1 1))
-                             (make-circle-stencil
-                               scale-dot-radius scale-dot-thick #t)))
+              (parenthesized
+                (if (not (null? (dot-is-parenthesized mypair)))
+                    (dot-is-parenthesized mypair)
+                    #f))
+              (parenthesis-color
+                (if (not (null? (default-paren-color mypair)))
+                    (default-paren-color mypair)
+                    #f))
+              (inverted
+                (if (not (null? (dot-is-inverted mypair)))
+                    (dot-is-inverted mypair)
+                    #f))
+              (dot-color-is-white?
+                (or inverted
+                    (and (eq? default-dot-color 'white) (not inverted))))
+              (what-color
+                (x11-color
+                  (cond ((and inverted
+                              (not (dot-has-color mypair))
+                              (not (eq? default-dot-color 'white)))
+                          (or default-dot-color 'black))
+                        (dot-color-is-white?
+                          (or (dot-has-color mypair) 'black))
+                        (else
+                          (or (dot-has-color mypair)
+                              default-dot-color
+                              'black)))))
+              (inverted-stil
+                (lambda (color)
+                  (ly:stencil-add
+                    (stencil-with-color
+                      (make-circle-stencil
+                        scale-dot-radius scale-dot-thick #t)
+                      color)
+                    (stencil-with-color
+                      (make-circle-stencil
+                        (- scale-dot-radius (* 0.5 scale-dot-thick))
+                        0  #t)
+                      (x11-color 'white)))))
+              (dot-stencil
+                (if dot-color-is-white?
+                    (inverted-stil what-color)
+                    (stencil-with-color
+                      (make-circle-stencil
+                         scale-dot-radius scale-dot-thick #t)
+                      what-color)))
+              (par-dot-stencil
+                (let ((paren-color
+                        (if (and parenthesis-color
+                                 (not (eq? default-dot-color 'white)))
+                            (x11-color (or default-dot-color 'black))
+                            what-color)))
+                 (stencil-with-color
+                   (parenthesize-stencil
+                     dot-stencil      ;; stencil
+                     (* size th 0.75) ;; half-thickness
+                     (* 0.15 size)    ;;width
+                     0                ;; angularity
+                     paren-padding    ;; padding
+                     )
+                   paren-color)))
+              (final-dot-stencil
+                  (if parenthesized
+                      par-dot-stencil
+                      dot-stencil))
               (positioned-dot
-                (ly:stencil-translate dot-stencil dot-coordinates))
+               (ly:stencil-translate final-dot-stencil dot-coordinates))
               (labeled-dot-stencil
-                (cond
-                  ((or (eq? finger '())(eq? finger-code 'none))
-                   positioned-dot)
-                  ((eq? finger-code 'in-dot)
-                   (let ((finger-label
-                           (centered-stencil
-                             (sans-serif-stencil
-                               layout props dot-label-font-mag finger))))
-                     (ly:stencil-translate
-                       (ly:stencil-add
-                         dot-stencil
-                         (if (eq? dot-color 'white)
-                           finger-label
-                           (ly:stencil-in-color finger-label 1 1 1)))
-                       dot-coordinates)))
-                  ((eq? finger-code 'below-string)
-                   (let* ((label-stencil
-                            (centered-stencil
+               (cond
+                ((or (eq? finger '())(eq? finger-code 'none))
+                 positioned-dot)
+                ((eq? finger-code 'in-dot)
+                 (let* ((finger-stil
+                          (if (not (null? finger))
                               (sans-serif-stencil
-                                layout props string-label-font-mag
-                                finger)))
-                          (label-fret-offset
-                            (stencil-fretboard-offset
-                              label-stencil 'fret orientation))
-                          (label-fret-coordinate
-                            (+ (* size
-                                  (+ 1 my-fret-count finger-label-padding))
-                               label-fret-offset))
-                          (label-string-coordinate string-coordinate)
-                          (label-translation
-                            (stencil-coordinates
-                              label-fret-coordinate
-                              label-string-coordinate)))
-                     (ly:stencil-add
-                       positioned-dot
-                       (ly:stencil-translate
-                         label-stencil
-                         label-translation))))
-                  (else ;unknown finger-code
-                    positioned-dot))))
-         (if (null? restlist)
-           labeled-dot-stencil
-           (ly:stencil-add
+                                 layout props dot-label-font-mag finger)
+                              empty-stencil))
+                        (finger-stil-length
+                          (interval-length (ly:stencil-extent finger-stil X)))
+                        (finger-stil-height
+                          (interval-length (ly:stencil-extent finger-stil Y)))
+                        (dot-stencil-radius
+                          (/ (interval-length (ly:stencil-extent dot-stencil Y))
+                             2))
+                        (scale-factor
+                          (/ dot-stencil-radius
+                             ;; Calculate the radius of the circle through the
+                             ;; corners of the box containing the finger-stil.
+                             ;; Give it a little padding. The value, (* 2 th),
+                             ;; is my choice
+                             (+
+                               (sqrt
+                                  (+ (expt (/ finger-stil-length 2) 2)
+                                     (expt (/ finger-stil-height 2) 2)))
+                                (* 2 th))))
+                        (finger-label
+                         (centered-stencil
+                          (ly:stencil-scale
+                           (sans-serif-stencil
+                            layout props
+                            dot-label-font-mag
+                            finger)
+                           scale-factor scale-factor))))
+                   (ly:stencil-translate
+                    (ly:stencil-add
+                     final-dot-stencil
+                     (if dot-color-is-white?
+                         (stencil-with-color
+                            finger-label
+                            what-color)
+                         (stencil-with-color finger-label white)))
+                    dot-coordinates)))
+                ((eq? finger-code 'below-string)
+                 (let* ((label-stencil
+                         (centered-stencil
+                          (sans-serif-stencil
+                           layout props string-label-font-mag
+                           finger)))
+                        (label-fret-offset
+                         (stencil-fretboard-offset
+                          label-stencil 'fret orientation))
+                        (label-fret-coordinate
+                         ;; (1) Move the below-string-finger-codes to the bottom
+                         ;;     edge of the string, i.e.
+                         ;;       (* (1+  my-fret-count) fret-distance)
+                         ;; (2) add `finger-label-padding' (a hardcoded
+                         ;;     correction-value to get a bit default padding).
+                         ;;     TODO: make it a property?
+                         ;; (3) scale this with `size'
+                         ;; (4) add `label-fret-offset', to get the final
+                         ;;     padding
+                         (+
+                            (* size
+                               (+ (* (1+  my-fret-count) fret-distance)
+                                  finger-label-padding))
+                            label-fret-offset))
+                        (label-string-coordinate string-coordinate)
+                        (label-translation
+                         (stencil-coordinates
+                          label-fret-coordinate
+                          label-string-coordinate)))
+                   (ly:stencil-add
+                    positioned-dot
+                    (ly:stencil-translate
+                     label-stencil
+                     label-translation))))
+                (else ;unknown finger-code
+                 positioned-dot))))
+        (if (null? restlist)
+            labeled-dot-stencil
+            (ly:stencil-add
              (draw-dots restlist)
              labeled-dot-stencil))))
 
-     (define (draw-thick-zero-fret)
-       "Draw a thick zeroth fret for a fret diagram whose base fret is 1."
-       (let* ((half-lowest-string-thickness
-                (* 0.5 th (string-thickness string-count thickness-factor)))
-              (half-thick (* 0.5 sth))
-              (top-fret-thick
-                (* sth (assoc-get 'top-fret-thickness details 3.0)))
-              (start-string-coordinate (- half-lowest-string-thickness))
-              (end-string-coordinate (+ (* size (1- string-count)) half-thick))
-              (start-fret-coordinate half-thick)
-              (end-fret-coordinate (- half-thick top-fret-thick))
-              (lower-left
-                (stencil-coordinates
-                  start-fret-coordinate start-string-coordinate))
-              (upper-right
-                (stencil-coordinates
-                  end-fret-coordinate end-string-coordinate)))
-         (ly:round-filled-box
-           (cons (car lower-left) (car upper-right))
-           (cons (cdr lower-left) (cdr upper-right))
-           sth)))
-
-     (define (draw-xo xo-list)
-       "Put open and mute string indications on diagram, as contained in
+    (define (draw-thick-zero-fret)
+      "Draw a thick zeroth fret for a fret diagram whose base fret is 1."
+      (let* ((half-lowest-string-thickness
+              (* 0.5 th (string-thickness string-count thickness-factor)))
+             (half-thick (* 0.5 sth))
+             (top-fret-thick
+              (* sth (assoc-get 'top-fret-thickness details 3.0)))
+             (start-string-coordinate (- half-lowest-string-thickness))
+             (end-string-coordinate
+                 (+ (* size string-distance (1- string-count)) half-thick))
+             (start-fret-coordinate half-thick)
+             (end-fret-coordinate (- half-thick top-fret-thick))
+             (lower-left
+              (stencil-coordinates
+               start-fret-coordinate start-string-coordinate))
+             (upper-right
+              (stencil-coordinates
+               end-fret-coordinate end-string-coordinate)))
+        (ly:round-filled-box
+         ;; Put limits in order, or else the intervals are considered empty
+         (ordered-cons (car lower-left) (car upper-right))
+         (ordered-cons (cdr lower-left) (cdr upper-right))
+         sth)))
+
+    (define (draw-xo xo-list)
+      "Put open and mute string indications on diagram, as contained in
 @var{xo-list}."
-       (let* ((xo-font-mag
-                (* size (assoc-get
-                          'xo-font-magnification details
-                          (cond ((or (eq? orientation 'landscape)
-                                     (eq? orientation 'opposing-landscape))
-                                 0.4)
-                                (else 0.4)))))
-              (mypair (car xo-list))
-              (restlist (cdr xo-list))
-              (glyph-string (if (eq? (car mypair) 'mute)
-                              (assoc-get 'mute-string details "X")
-                              (assoc-get 'open-string details "O")))
-              (glyph-string-coordinate (* (- string-count (cadr mypair)) size))
-              (glyph-stencil
-                (centered-stencil
-                  (sans-serif-stencil
-                    layout props (* size xo-font-mag) glyph-string)))
-              (glyph-stencil-coordinates
-                (stencil-coordinates 0 glyph-string-coordinate))
-              (positioned-glyph
-                (ly:stencil-translate
-                  glyph-stencil
-                  glyph-stencil-coordinates)))
-         (if (null? restlist)
-           positioned-glyph
-           (ly:stencil-add
+      (let* ((xo-font-mag
+              (assoc-get 'xo-font-magnification details
+                         (cond ((or (eq? orientation 'landscape)
+                                    (eq? orientation 'opposing-landscape))
+                                0.4)
+                               (else 0.4))))
+             (mypair (car xo-list))
+             (restlist (cdr xo-list))
+             (glyph-string (if (eq? (car mypair) 'mute)
+                               (assoc-get 'mute-string details "X")
+                               (assoc-get 'open-string details "O")))
+             (glyph-string-coordinate
+              (* (- string-count (cadr mypair)) string-distance size))
+             (glyph-stencil
+              (centered-stencil
+               (sans-serif-stencil
+                layout props (* size xo-font-mag) glyph-string)))
+             (glyph-stencil-coordinates
+              (stencil-coordinates 0 glyph-string-coordinate))
+             (positioned-glyph
+              (ly:stencil-translate
+               glyph-stencil
+               glyph-stencil-coordinates)))
+        (if (null? restlist)
+            positioned-glyph
+            (ly:stencil-add
              positioned-glyph
              (draw-xo restlist)))))
 
-       (define (draw-capo fret)
-         "Draw a capo indicator across the full width of the fret-board
+    (define (draw-capo fret)
+      "Draw a capo indicator across the full width of the fret-board
 at @var{fret}."
-         (let* ((capo-thick
-                  (* size (assoc-get 'capo-thickness details 0.5)))
-                (half-thick (* capo-thick 0.5))
-                (last-string-position 0)
-                (first-string-position (* size (- string-count 1)))
-                (fret-position ( * size (1- (+ dot-position fret))))
-                (start-point
-                  (stencil-coordinates
-                    fret-position
-                    first-string-position))
-                (end-point
-                  (stencil-coordinates
-                    fret-position
-                    last-string-position)))
-           (make-line-stencil
-             capo-thick
-             (car start-point) (cdr start-point)
-             (car end-point) (cdr end-point))))
-
-        (define (label-fret fret-range)
-          "Label the base fret on a fret diagram"
-          (let* ((base-fret (car fret-range))
-                 (label-font-mag (assoc-get 'fret-label-font-mag details 0.5))
-                 (label-space (* 0.5 size))
-                 (label-dir (assoc-get 'label-dir details RIGHT))
-                 (label-vertical-offset
-                   (assoc-get 'fret-label-vertical-offset details 0))
-                 (number-type
-                   (assoc-get 'number-type details 'roman-lower))
-                 (label-text
-                   (cond
-                     ((equal? number-type 'roman-lower)
-                      (fancy-format #f "~(~@r~)" base-fret))
-                     ((equal? number-type 'roman-upper)
-                      (fancy-format #f "~@r" base-fret))
-                     ((equal? 'arabic number-type)
-                      (fancy-format #f "~d" base-fret))
-                     (else (fancy-format #f "~(~@r~)" base-fret))))
-                 (label-stencil
-                   (centered-stencil
-                     (sans-serif-stencil
-                       layout props (* size label-font-mag) label-text)))
-                 (label-half-width
-                   (stencil-fretboard-offset
-                     label-stencil
-                     'string
-                     orientation))
-                 (label-outside-diagram (+ label-space label-half-width)))
-            (ly:stencil-translate
-              label-stencil
+      (let* ((capo-thick
+              (* size (assoc-get 'capo-thickness details 0.5)))
+             (half-thick (* capo-thick 0.5))
+             (last-string-position 0)
+             (first-string-position (* size (- string-count 1)))
+             (fret-position (* size (1- (+ dot-position fret))))
+             (start-point
               (stencil-coordinates
-                (1+ (* size label-vertical-offset))
-                (if (eq? label-dir LEFT)
-                  (- label-outside-diagram)
-                  (+ (* size (1- string-count)) label-outside-diagram))))))
-
-
-              ; Here is the body of make-fret-diagram
-              ;
+               (* fret-distance fret-position)
+               (* string-distance first-string-position)))
+             (end-point
+              (stencil-coordinates
+               (* fret-distance fret-position)
+               last-string-position)))
+        (make-line-stencil
+         capo-thick
+         (car start-point) (cdr start-point)
+         (car end-point) (cdr end-point))))
+
+    (define (label-fret fret-range)
+      "Label the base fret on a fret diagram"
+      (let* ((base-fret (car fret-range))
+             (label-font-mag (assoc-get 'fret-label-font-mag details 0.5))
+             (label-space (* 0.5 size))
+             (label-dir (assoc-get 'label-dir details RIGHT))
+             (label-vertical-offset
+              (assoc-get 'fret-label-vertical-offset details 0))
+             (label-horizontal-offset
+              (assoc-get 'fret-label-horizontal-offset details 0))
+             (number-type
+              (assoc-get 'number-type details 'roman-lower))
+             (label-text
+              (number-format number-type base-fret
+                             (assoc-get 'fret-label-custom-format
+                                         details "~a")))
+             (label-stencil
+              (centered-stencil
+               (sans-serif-stencil
+                layout props (* size label-font-mag) label-text)))
+             (label-half-width
+              (stencil-fretboard-offset
+               label-stencil
+               'string
+               orientation))
+             (label-outside-diagram
+               (+ label-space
+                  (* size label-horizontal-offset)
+                  label-half-width)))
+        (ly:stencil-translate
+         label-stencil
+         (stencil-coordinates
+          (* size fret-distance (1+ label-vertical-offset))
+          (if (eqv? label-dir LEFT)
+              (- label-outside-diagram)
+              (+ (* size string-distance (1- string-count))
+                 label-outside-diagram))))))
+
+    ;; Here is the body of make-fret-diagram
 
     (set! fret-diagram-stencil
-      (ly:stencil-add (draw-strings) (draw-frets)))
+          (ly:stencil-add (draw-strings) (draw-frets)))
     (if (and (not (null? barre-list))
              (not (eq? 'none barre-type)))
-      (set! fret-diagram-stencil
-        (ly:stencil-add
-          (draw-barre barre-list)
-          fret-diagram-stencil)))
+        (set! fret-diagram-stencil
+              (ly:stencil-add
+               (draw-barre barre-list)
+               fret-diagram-stencil)))
     (if (not (null? dot-list))
-      (set! fret-diagram-stencil
-        (ly:stencil-add
-          fret-diagram-stencil
-          (draw-dots dot-list))))
+        (set! fret-diagram-stencil
+              (ly:stencil-add
+               fret-diagram-stencil
+               (draw-dots dot-list))))
     (if (= (car fret-range) 1)
-      (set! fret-diagram-stencil
-        (ly:stencil-add
-          fret-diagram-stencil
-          (draw-thick-zero-fret))))
+        (set! fret-diagram-stencil
+              (ly:stencil-add
+               fret-diagram-stencil
+               (draw-thick-zero-fret))))
     (if (not (null? xo-list))
-      (let* ((diagram-fret-top
-               (car (stencil-fretboard-extent
+        (let* ((diagram-fret-top
+                (car (stencil-fretboard-extent
                       fret-diagram-stencil
                       'fret
                       orientation)))
-             (xo-stencil (draw-xo xo-list))
-             (xo-fret-offset
-               (stencil-fretboard-offset
+               (xo-stencil (draw-xo xo-list))
+               (xo-fret-offset
+                (stencil-fretboard-offset
                  xo-stencil 'fret orientation))
-             (xo-stencil-offset
-              (stencil-coordinate-offset
-               (- diagram-fret-top
-                  xo-fret-offset
-                  (* size xo-padding))
-               0)))
-        (set! fret-diagram-stencil
-          (ly:stencil-add
-            fret-diagram-stencil
-            (ly:stencil-translate
-              xo-stencil
-              xo-stencil-offset)))))
+               (xo-stencil-offset
+                (stencil-coordinate-offset
+                 (- diagram-fret-top
+                    xo-fret-offset
+                    (* size xo-padding))
+                 0)))
+          (set! fret-diagram-stencil
+                (ly:stencil-add
+                 fret-diagram-stencil
+                 (ly:stencil-translate
+                  xo-stencil
+                  xo-stencil-offset)))))
     (if (> capo-fret 0)
-      (set! fret-diagram-stencil
-        (ly:stencil-add
-          fret-diagram-stencil
-          (draw-capo capo-fret))))
+        (set! fret-diagram-stencil
+              (ly:stencil-add
+               fret-diagram-stencil
+               (draw-capo capo-fret))))
     (if (> (car fret-range) 1)
-      (set! fret-diagram-stencil
-        (ly:stencil-add
-          fret-diagram-stencil
-          (label-fret fret-range))))
+        (set! fret-diagram-stencil
+              (ly:stencil-add
+               fret-diagram-stencil
+               (label-fret fret-range))))
     (ly:stencil-aligned-to fret-diagram-stencil X alignment)))
 
 (define (fret-parse-definition-string props definition-string)
- "Parse a fret diagram string and return a pair containing:
+  "Parse a fret diagram string and return a pair containing:
 @var{props}, modified as necessary by the definition-string
 a fret-indication list with the appropriate values"
- (let* ((fret-count 4)
-        (string-count 6)
-        (fret-range (cons 1 fret-count))
-        (barre-list '())
-        (dot-list '())
-        (xo-list '())
-        (output-list '())
-        (new-props '())
-        (details (merge-details 'fret-diagram-details props '()))
-        (items (string-split definition-string #\;)))
-   (let parse-item ((myitems items))
-     (if (not (null? (cdr myitems)))
-         (let ((test-string (car myitems)))
-           (case (car (string->list (substring test-string 0 1)))
-             ((#\s) (let ((size (get-numeric-from-key test-string)))
-                      (set! props (prepend-alist-chain 'size size props))))
-             ((#\f) (let* ((finger-code (get-numeric-from-key test-string))
-                           (finger-id (case finger-code
-                                        ((0) 'none)
-                                        ((1) 'in-dot)
-                                        ((2) 'below-string))))
-                      (set! details
-                            (acons 'finger-code finger-id details))))
-             ((#\c) (set! output-list
-                          (cons-fret
-                           (cons
-                            'barre
-                            (numerify
-                             (string-split (substring test-string 2) #\-)))
-                           output-list)))
-             ((#\h) (let ((fret-count (get-numeric-from-key test-string)))
-                      (set! details
-                            (acons 'fret-count fret-count details))))
-             ((#\w) (let ((string-count (get-numeric-from-key test-string)))
-                      (set! details
-                            (acons 'string-count string-count details))))
-             ((#\d) (let ((dot-size (get-numeric-from-key test-string)))
-                      (set! details
-                            (acons 'dot-radius dot-size details))))
-             ((#\p) (let ((dot-position (get-numeric-from-key test-string)))
-                      (set! details
-                            (acons 'dot-position dot-position details))))
-             (else
-              (let ((this-list (string-split test-string #\-)))
-                (if (string->number (cadr this-list))
-                    (set! output-list
-                          (cons-fret
-                           (cons 'place-fret (numerify this-list))
-                           output-list))
-                    (if (equal? (cadr this-list) "x" )
-                        (set! output-list
-                              (cons-fret
-                               (list 'mute (string->number (car this-list)))
-                               output-list))
-                        (set! output-list
-                              (cons-fret
-                               (list 'open (string->number (car this-list)))
-                               output-list)))))))
-           (parse-item (cdr myitems)))))
-   ;  add the modified details
-   (set! props
-         (prepend-alist-chain 'fret-diagram-details details props))
-   `(,props . ,output-list))) ;ugh -- hard-coded spell -- procedure better
+  (let* ((fret-count 4)
+         (string-count 6)
+         (fret-range (cons 1 fret-count))
+         (barre-list '())
+         (dot-list '())
+         (xo-list '())
+         (output-list '())
+         (new-props '())
+         (details (merge-details 'fret-diagram-details props '()))
+         ;; remove whitespace-characters from definition-string
+         (cleared-string (remove-whitespace definition-string))
+         (items (string-split cleared-string #\;)))
+    (let parse-item ((myitems items))
+      (if (not (null? (cdr myitems)))
+          (let ((test-string (car myitems)))
+            (case (car (string->list (substring test-string 0 1)))
+              ((#\s) (let ((size (get-numeric-from-key test-string)))
+                       (set! props (prepend-alist-chain 'size size props))))
+              ((#\t) (let ((th (get-numeric-from-key test-string)))
+                       (set! props (prepend-alist-chain 'thickness th props))))
+              ((#\f) (let* ((finger-code (get-numeric-from-key test-string))
+                            (finger-id (case finger-code
+                                         ((0) 'none)
+                                         ((1) 'in-dot)
+                                         ((2) 'below-string))))
+                       (set! details
+                             (acons 'finger-code finger-id details))))
+              ((#\c) (set! output-list
+                           (cons-fret
+                            (cons
+                             'barre
+                             (numerify
+                              (string-split (substring test-string 2) #\-)))
+                            output-list)))
+              ((#\h) (let ((fret-count (get-numeric-from-key test-string)))
+                       (set! details
+                             (acons 'fret-count fret-count details))))
+              ((#\w) (let ((string-count (get-numeric-from-key test-string)))
+                       (set! details
+                             (acons 'string-count string-count details))))
+              ((#\d) (let ((dot-size (get-numeric-from-key test-string)))
+                       (set! details
+                             (acons 'dot-radius dot-size details))))
+              ((#\p) (let ((dot-position (get-numeric-from-key test-string)))
+                       (set! details
+                             (acons 'dot-position dot-position details))))
+              (else
+               (let* ((this-list (string-split test-string #\-))
+                      (fret-number (string->number (car this-list))))
+                 ;; If none of the above applies, `fret-number' needs to be a
+                 ;; number. Throw an error, if not.
+                 (if (not fret-number)
+                   (ly:error
+                     "Unhandled entry in fret-diagrams \"~a\" in \"~a\""
+                     (car this-list)
+                     test-string))
+                 (if (string->number (cadr this-list))
+                     (set! output-list
+                           (cons-fret
+                            (cons 'place-fret (numerify this-list))
+                            output-list))
+                     (if (equal? (cadr this-list) "x" )
+                         (set! output-list
+                               (cons-fret
+                                (list 'mute fret-number)
+                                output-list))
+                         (set! output-list
+                               (cons-fret
+                                (list 'open fret-number)
+                                output-list)))))))
+            (parse-item (cdr myitems)))))
+    ;; add the modified details
+    (set! props
+          (prepend-alist-chain 'fret-diagram-details details props))
+    `(,props . ,output-list))) ;ugh -- hard-coded spell -- procedure better
 
 (define-public
   (fret-parse-terse-definition-string props definition-string)
@@ -859,7 +1018,7 @@ return a pair containing:
 @var{props}, modified to include the string-count determined by the
 definition-string, and
 a fret-indication list with the appropriate values"
-;TODO -- change syntax to fret\string-finger
+  ;; TODO -- change syntax to fret\string-finger
 
   (let* ((details (merge-details 'fret-diagram-details props '()))
          (barre-start-list '())
@@ -932,9 +1091,9 @@ a fret-indication list with the appropriate values"
   (pair?) ; argument type (list, but use pair? for speed)
   #:category instrument-specific-markup ; markup type
   #:properties ((align-dir -0.4) ; properties and defaults
-		(size 1.0)
-		(fret-diagram-details)
-		(thickness 0.5))
+                (size 1.0)
+                (fret-diagram-details)
+                (thickness 0.5))
   "Make a fret diagram containing the symbols indicated in @var{marking-list}.
 
   For example,
@@ -965,13 +1124,31 @@ to string @var{end-string} at fret @var{fret-number}.
 Place a capo indicator (a large solid bar) across the entire fretboard
 at fret location @var{fret-number}.  Also, set fret @var{fret-number}
 to be the lowest fret on the fret diagram.
-
-@item (place-fret @var{string-number} @var{fret-number} @var{finger-value})
+@item
+(place-fret @var{string-number}
+            @var{fret-number}
+            [@var{finger-value}]
+            [@var{color-modifier}]
+            [@var{color}]
+            [@code{'parenthesized} [@code{'default-paren-color}]])
 Place a fret playing indication on string @var{string-number} at fret
-@var{fret-number} with an optional fingering label @var{finger-value}.
+@var{fret-number} with an optional fingering label @var{finger-value},
+an optional color modifier @var{color-modifier}, an optional color
+@var{color}, an optional parenthesis @code{'parenthesized} and an
+optional paranthesis color @code{'default-paren-color}.
 By default, the fret playing indicator is a solid dot.  This can be
-changed by setting the value of the variable @var{dot-color}.  If the
-@var{finger} part of the @code{place-fret} element is present,
+globally changed by setting the value of the variable @var{dot-color}
+or for a single dot by setting the value of @var{color}.  The dot can
+be parenthesized by adding @code{'parenthesized}.  By default the
+color for the parenthesis is taken from the dot.  Adding
+@code{'default-paren-color} will take the parenthesis-color from the
+global @var{dot-color}, as a fall-back black will be used.
+Setting @var{color-modifier} to @code{inverted} inverts the dot color
+for a specific fingering.
+The values for @var{string-number}, @var{fret-number}, and the optional
+@var{finger} should be entered first in that order.
+The order of the other optional arguments does not matter.
+If the @var{finger} part of the @code{place-fret} element is present,
 @var{finger-value} will be displayed according to the setting of the
 variable @var{finger-code}.  There is no limit to the number of fret
 indications per string.
@@ -1009,8 +1186,9 @@ spaces).
 Default:@tie{}1.
 
 @item
-@code{t:}@var{number} -- Set the line thickness (in staff spaces).
-Default:@tie{}0.05.
+@code{t:}@var{number} -- Set the line thickness (relative to normal
+line thickness).
+Default:@tie{}0.5.
 
 @item
 @code{h:}@var{number} -- Set the height of the diagram in frets.
@@ -1095,13 +1273,13 @@ If there are multiple fret indicators desired on a string, they
 should be separated by spaces.
 
 @item
-Fingerings are given by following the fret number with a @code{-},
+Fingerings are given by following the fret number with a @w{@code{-},}
 followed by the finger indicator, e.g. @samp{3-2} for playing the third
 fret with the second finger.
 
 @item
 Where a barre indicator is desired, follow the fret (or fingering) symbol
-with @code{-(} to start a barre and @code{-)} to end the barre.
+with @w{@code{-(}} to start a barre and @w{@code{-)}} to end the barre.
 
 @end itemize"
   ;; TODO -- change syntax to fret\string-finger
@@ -1110,5 +1288,3 @@ with @code{-(} to start a barre and @code{-)} to end the barre.
     (fret-diagram-verbose-markup layout
                                  (car definition-list)
                                  (cdr definition-list))))
-
-