X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;ds=sidebyside;f=scm%2Foutput-svg.scm;h=8a52ed6a3d25a016bd788b592286a1abdb05fb0c;hb=26a9e9b251e5a9529e4f4e6920830f098a41e7ea;hp=96dbfd1aa26192e801ae1949716f5bf4bee9e26e;hpb=413427dd5218dac5ca4627360d45516345632005;p=lilypond.git

diff --git a/scm/output-svg.scm b/scm/output-svg.scm
index 96dbfd1aa2..8a52ed6a3d 100644
--- a/scm/output-svg.scm
+++ b/scm/output-svg.scm
@@ -1,242 +1,481 @@
-;;;; output-svg.scm -- implement Scheme output routines for SVG1
+;;;; output-svg.scm -- implement Scheme output routines for SVG
 ;;;;
 ;;;;  source file of the GNU LilyPond music typesetter
-;;;; 
-;;;; (c)  2002--2004 Jan Nieuwenhuizen <janneke@gnu.org>
-
-;;;; http://www.w3.org/TR/SVG11
-
-;;;; TODO:
-;;;;  * check: blot+scaling
-;;;;  * inkscape page/pageSet support
-;;;;  * inkscape SVG-font support
-;;;;    - use fontconfig/fc-cache for now, see output-gnome.scm
+;;;;
+;;;; (c) 2002--2009 Jan Nieuwenhuizen <janneke@gnu.org>
+;;;;                Patrick McCarty <pnorcks@gmail.com>
 
-(debug-enable 'backtrace)
 (define-module (scm output-svg))
 (define this-module (current-module))
 
 (use-modules
- (guile)
- (ice-9 regex)
- (lily)
- (srfi srfi-13))
+  (guile)
+  (ice-9 regex)
+  (ice-9 format)
+  (lily)
+  (srfi srfi-1)
+  (srfi srfi-13))
 
-;; GLobals
-;; FIXME: 2?
-(define output-scale (* 2 scale-to-unit))
+(define fancy-format format)
+(define format ergonomic-simple-format)
 
-(define (debugf string . rest)
-  (if #f
-      (apply stderr (cons string rest))))
+(define lily-unit-length 1.7573)
 
 (define (dispatch expr)
   (let ((keyword (car expr)))
     (cond
      ((eq? keyword 'some-func) "")
-     ;;((eq? keyword 'placebox) (dispatch (cadddr expr)))
      (else
       (if (module-defined? this-module keyword)
 	  (apply (eval keyword this-module) (cdr expr))
 	  (begin
-	    (display
-	     (string-append "undefined: " (symbol->string keyword) "\n"))
+	    (ly:warning (_ "undefined: ~S") keyword)
 	    ""))))))
-  
+
 ;; Helper functions
 (define-public (attributes attributes-alist)
   (apply string-append
-	 (map (lambda (x) (format #f " ~s=\"~a\"" (car x) (cdr x)))
+	 (map (lambda (x)
+		(let ((attr (car x))
+		      (value (cdr x)))
+		  (if (number? value)
+		      (set! value (ly:format "~4f" value)))
+		  (format " ~s=\"~a\"" attr value)))
 	      attributes-alist)))
 
 (define-public (eo entity . attributes-alist)
-  (format #f "<~S~a>\n" entity (attributes attributes-alist)))
+  "o = open"
+  (format "<~S~a>\n" entity (attributes attributes-alist)))
 
 (define-public (eoc entity . attributes-alist)
-  (format #f "<~S~a/>\n" entity (attributes attributes-alist)))
+  " oc = open/close"
+  (format "<~S~a/>\n" entity (attributes attributes-alist)))
 
 (define-public (ec entity)
-  (format #f "</~S>\n" entity))
+  "c = close"
+  (format "</~S>\n" entity))
+
+(define-public (comment s)
+  (string-append "<!-- " s " -->\n"))
 
 (define-public (entity entity string . attributes-alist)
   (if (equal? string "")
       (apply eoc entity attributes-alist)
       (string-append
-       (apply eo (cons entity attributes-alist)) string (ec entity))))
+	(apply eo (cons entity attributes-alist)) string (ec entity))))
 
 (define (offset->point o)
-  (format #f " ~S,~S" (car o) (cdr o)))
+  (ly:format "~4f ~4f" (car o) (- (cdr o))))
+
+(define (number-list->point lst)
+  (define (helper lst)
+    (if (null? lst)
+	'()
+	(cons (format "~S ~S" (car lst) (- (cadr lst)))
+	      (helper (cddr lst)))))
+
+  (string-join (helper lst) " "))
+
 
 (define (svg-bezier lst close)
   (let* ((c0 (car (list-tail lst 3)))
 	 (c123 (list-head lst 3)))
     (string-append
-     (if (not close) "M " "L ")
-     (offset->point c0)
-     "C " (apply string-append (map offset->point c123))
-     (if (not close) "" (string-append
-			 "L " (offset->point close))))))
+      (if (not close) "M" "L")
+      (offset->point c0)
+      "C" (string-join (map offset->point c123) " ")
+      (if (not close) "" "z"))))
 
 (define (sqr x)
   (* x x))
 
-(define (font-size font)
-  (let* ((designsize (ly:font-design-size font))
-	 (magnification (* (ly:font-magnification font)))
-	 (ops 2)
-	 (scaling (* ops magnification designsize)))
-    (debugf "scaling:~S\n" scaling)
-    (debugf "magnification:~S\n" magnification)
-    (debugf "design:~S\n" designsize)
-    scaling))
-
 (define (integer->entity integer)
-  (format #f "&#x~x;" integer))
-		   
+  (fancy-format "&#x~x;" integer))
+
 (define (char->entity char)
   (integer->entity (char->integer char)))
-		   
+
 (define (string->entities string)
   (apply string-append
 	 (map (lambda (x) (char->entity x)) (string->list string))))
 
-(define (svg-font font)
-  (let* ((encoding (ly:font-encoding font))
-	 (anchor (if (memq encoding '(fetaMusic fetaBraces)) 'start 'start))
-	 (family (font-family font)))
-   (format #f "font-family:~a;font-style:~a;font-size:~a;text-anchor:~S;"
-	   (otf-name-mangling font family)
-	   (otf-style-mangling font family)
-	   (font-size font) anchor)))
+(define svg-element-regexp
+  (make-regexp "^(<[a-z]+) ?(.*>)"))
+
+(define scaled-element-regexp
+  (make-regexp "^(<[a-z]+ transform=\")(scale.[-0-9. ]+,[-0-9. ]+.\" .*>)"))
+
+(define pango-description-regexp-comma
+  (make-regexp ",( Bold)?( Italic)?( Small-Caps)? ([0-9.]+)$"))
+
+(define pango-description-regexp-nocomma
+  (make-regexp "( Bold)?( Italic)?( Small-Caps)? ([0-9.]+)$"))
+
+(define (pango-description-to-text str expr)
+  (define alist '())
+  (define (set-attribute attr val)
+    (set! alist (assoc-set! alist attr val)))
+  (let*
+    ((match-1 (regexp-exec pango-description-regexp-comma str))
+     (match-2 (regexp-exec pango-description-regexp-nocomma str))
+     (match (if match-1
+		match-1
+		match-2)))
+
+    (if (regexp-match? match)
+	(begin
+	  (set-attribute 'font-family (match:prefix match))
+	  (if (string? (match:substring match 1))
+	      (set-attribute 'font-weight "bold"))
+	  (if (string? (match:substring match 2))
+	      (set-attribute 'font-style "italic"))
+	  (if (string? (match:substring match 3))
+	      (set-attribute 'font-variant "small-caps"))
+	  (set-attribute 'font-size
+			 (/ (string->number (match:substring match 4))
+			    lily-unit-length))
+	  (set-attribute 'text-anchor "start")
+	  (set-attribute 'fill "currentColor"))
+	(ly:warning (_ "cannot decypher Pango description: ~a") str))
+
+    (apply entity 'text expr (reverse! alist))))
+
+(define (dump-path path scale . rest)
+  (define alist '())
+  (define (set-attribute attr val)
+    (set! alist (assoc-set! alist attr val)))
+  (if (not (null? rest))
+      (let* ((dx (car rest))
+	     (dy (cadr rest))
+	     (total-x (+ dx next-horiz-adv)))
+	(if (or (not (zero? total-x))
+		(not (zero? dy)))
+	    (let ((x (ly:format "~4f" total-x))
+		  (y (ly:format "~4f" dy)))
+	      (set-attribute 'transform
+			     (string-append
+			       "translate(" x ", " y ") "
+			       "scale(" scale ", -" scale ")")))
+	    (set-attribute 'transform
+			   (string-append
+			     "scale(" scale ", -" scale ")"))))
+      (set-attribute 'transform (string-append
+				  "scale(" scale ", -" scale ")")))
+
+  (set-attribute 'd path)
+  (set-attribute 'fill "currentColor")
+  (apply entity 'path "" (reverse alist)))
+
+
+;; A global variable for keeping track of the *cumulative*
+;; horizontal advance for glyph strings, but only if there
+;; is more than one glyph.
+(define next-horiz-adv 0.0)
+
+;; Matches the required "unicode" attribute from <glyph>
+(define glyph-unicode-value-regexp
+  (make-regexp "unicode=\"([^\"]+)\""))
+
+;; Matches the optional path data from <glyph>
+(define glyph-path-regexp
+  (make-regexp "d=\"([-MmZzLlHhVvCcSsQqTt0-9.\n ]*)\""))
+
+;; Matches a complete <glyph> element with the glyph-name
+;; attribute value of NAME.  For example:
+;;
+;; <glyph glyph-name="period" unicode="." horiz-adv-x="110"
+;; d="M0 55c0 30 25 55 55 55s55 -25 55
+;; -55s-25 -55 -55 -55s-55 25 -55 55z" />
+;;
+;; TODO: it would be better to use an XML library to extract
+;; the glyphs instead, and store them in a hash table.  --pmccarty
+;;
+(define (glyph-element-regexp name)
+  (make-regexp (string-append "<glyph"
+			      "(([\r\n\t ]+[-a-z]+=\"[^\"]*\")+)?"
+			      "[\r\n\t ]+glyph-name=\"("
+			      name
+			      ")\""
+			      "(([\r\n\t ]+[-a-z]+=\"[^\"]*\")+)?"
+			      "([\r\n\t ]+)?"
+			      "/>")))
+
+(define (extract-glyph all-glyphs name size . rest)
+  (let* ((new-name (regexp-quote name))
+	 (regexp (regexp-exec (glyph-element-regexp new-name) all-glyphs))
+	 (glyph (match:substring regexp))
+	 (unicode-attr (regexp-exec glyph-unicode-value-regexp glyph))
+	 (unicode-attr-value (match:substring unicode-attr 1))
+	 (unicode-attr? (regexp-match? unicode-attr))
+	 (d-attr (regexp-exec glyph-path-regexp glyph))
+	 (d-attr-value "")
+	 (d-attr? (regexp-match? d-attr))
+	 ;; TODO: not urgent, but do not hardcode this value
+	 (units-per-em 1000)
+	 (font-scale (ly:format "~4f" (/ size units-per-em)))
+	 (path ""))
+
+    (if (and unicode-attr? (not unicode-attr-value))
+	(ly:warning (_ "Glyph must have a unicode value")))
+
+    (if d-attr? (set! d-attr-value (match:substring d-attr 1)))
+
+    (cond (
+	   ;; Glyph-strings with path data
+	   (and d-attr? (not (null? rest)))
+	   (begin
+	     (set! path (apply dump-path d-attr-value
+					 font-scale
+					 (list (cadr rest) (caddr rest))))
+	     (set! next-horiz-adv (+ next-horiz-adv
+				     (car rest)))
+	     path))
+	  ;; Glyph-strings without path data ("space")
+	  ((and (not d-attr?) (not (null? rest)))
+	   (begin
+	     (set! next-horiz-adv (+ next-horiz-adv
+				     (car rest)))
+	     ""))
+	  ;; Font smobs with path data
+	  ((and d-attr? (null? rest))
+	    (set! path (dump-path d-attr-value font-scale))
+	    path)
+	  ;; Font smobs without path data ("space")
+	  (else
+	    ""))))
+
+(define (extract-glyph-info all-glyphs glyph size)
+  (let* ((offsets (list-head glyph 3))
+	 (glyph-name (car (reverse glyph))))
+    (apply extract-glyph all-glyphs glyph-name size offsets)))
+
+(define (svg-defs svg-font)
+  (let ((start (string-contains svg-font "<defs>"))
+	(end (string-contains svg-font "</defs>")))
+    (substring svg-font (+ start 7) (- end 1))))
+
+(define (cache-font svg-font size glyph)
+  (let ((all-glyphs (svg-defs (cached-file-contents svg-font))))
+    (if (list? glyph)
+	(extract-glyph-info all-glyphs glyph size)
+	(extract-glyph all-glyphs glyph size))))
+
+
+(define (feta-alphabet-to-path font size glyph)
+  (let* ((name-style (font-name-style font))
+	 (scaled-size (/ size lily-unit-length))
+	 (font-file (ly:find-file (string-append name-style ".svg"))))
+
+    (if font-file
+	(cache-font font-file scaled-size glyph)
+	(ly:warning (_ "cannot find SVG font ~S") font-file))))
+
+
+(define (font-smob-to-path font glyph)
+  (let* ((name-style (font-name-style font))
+	 (scaled-size (modified-font-metric-font-scaling font))
+	 (font-file (ly:find-file (string-append name-style ".svg"))))
+
+    (if font-file
+	(cache-font font-file scaled-size glyph)
+	(ly:warning (_ "cannot find SVG font ~S") font-file))))
+
 
 (define (fontify font expr)
-   (entity 'text expr (cons 'style (svg-font font))))
-
-;; FIXME
-(define-public (otf-name-mangling font family)
-  ;; Hmm, family is bigcheese20/26?
-  (if (string=? (substring family 0 (min (string-length family) 9))
-		"bigcheese")
-      "LilyPond"
-      (if (string=? family "aybabtu")
-	  "LilyPondBraces"
-	  family)))
-
-(define-public (otf-style-mangling font family)
-  ;; Hmm, family is bigcheese20/26?
-  (if (string=? (substring family 0 (min (string-length family) 9))
-		"bigcheese")
-      (substring family 9)
-      "Regular"))
+  (if (string? font)
+      (pango-description-to-text font expr)
+      (font-smob-to-path font expr)))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;; stencil outputters
 ;;;
 
-;;; catch-all for missing stuff
-;;; comment this out to see find out what functions you miss :-)
-(define (dummy . foo) "")
-(map (lambda (x) (module-define! this-module x dummy))
-     (append
-      (ly:all-stencil-expressions)
-      (ly:all-output-backend-commands)))
-
-(define (beam width slope thick blot-diameter)
-  (let* ((x width)
-	 (y (* slope width))
-	 (z (sqrt (+ (sqr x) (sqr y)))))
-    (entity 'rect ""
-	    ;; The stroke will stick out.  To use stroke,
-	    ;; the stroke-width must be subtracted from all other dimensions.
-	    ;;'(stroke-linejoin . "round")
-	    ;;'(stroke-linecap . "round")
-	    ;;`(stroke-width . ,blot-diameter)
-	    ;;'(stroke . "red")
-	    ;;'(fill . "orange")
-
-	    `(x . 0)
-	    `(y . ,(- (/ thick 2)))
-	    `(width . ,(+ width (* slope blot-diameter)))
-	    `(height . ,thick)
-	    `(rx . ,(/ blot-diameter 2))
-	    `(transform . ,(string-append
-			    (format #f "matrix (~f, ~f, 0, 1, 0, 0)"
-				    (/ x z) (* -1 (/ y z)))
-			    (format #f " scale (~f, ~f)"
-				    output-scale output-scale))))))
-
 (define (bezier-sandwich lst thick)
   (let* ((first (list-tail lst 4))
-	 (first-c0 (car (list-tail first 3)))
 	 (second (list-head lst 4)))
     (entity 'path ""
 	    '(stroke-linejoin . "round")
 	    '(stroke-linecap . "round")
+	    '(stroke . "currentColor")
+	    '(fill . "currentColor")
 	    `(stroke-width . ,thick)
-	    '(stroke . "black")
-	    '(fill . "black")
 	    `(d . ,(string-append (svg-bezier first #f)
-				  (svg-bezier second first-c0)))
-	  `(transform
-	    . ,(format #f "scale (~f, -~f)" output-scale output-scale)))))
+				  (svg-bezier second #t))))))
 
 (define (char font i)
   (dispatch
    `(fontify ,font ,(entity 'tspan (char->entity (integer->char i))))))
 
-(define-public (comment s)
-  (string-append "<!-- " s " !-->\n"))
-
-(define (dashed-line thick on off dx dy)
-  (draw-line thick 0 0 dx dy))
+(define (circle radius thick is-filled)
+  (entity
+   'circle ""
+   '(stroke-linejoin . "round")
+   '(stroke-linecap . "round")
+   `(fill . ,(if is-filled "currentColor" "none"))
+   `(stroke . "currentColor")
+   `(stroke-width . ,thick)
+   `(r . ,radius)))
+
+(define (dashed-line thick on off dx dy phase)
+  (draw-line thick 0 0 dx dy
+	     `(stroke-dasharray . ,(format "~a,~a" on off))))
+
+(define (draw-line thick x1 y1 x2 y2 . alist)
+  (apply entity 'line ""
+	 (append
+	  `((stroke-linejoin . "round")
+	    (stroke-linecap . "round")
+	    (stroke-width . ,thick)
+	    (stroke . "currentColor")
+	    (x1 . ,x1)
+	    (y1 . ,(- y1))
+	    (x2 . ,x2)
+	    (y2 . ,(- y2)))
+	  alist)))
+
+(define (ellipse x-radius y-radius thick is-filled)
+  (entity
+   'ellipse ""
+   '(stroke-linejoin . "round")
+   '(stroke-linecap . "round")
+   `(fill . ,(if is-filled "currentColor" "none"))
+   `(stroke . "currentColor")
+   `(stroke-width . ,thick)
+   `(rx . ,x-radius)
+   `(ry . ,y-radius)))
+
+(define (embedded-svg string)
+  string)
+
+(define (glyph-string font size cid glyphs)
+  (define path "")
+  (if (= 1 (length glyphs))
+      (set! path (feta-alphabet-to-path font size (car glyphs)))
+      (begin
+	(set! path
+	      (string-append (eo 'g)
+			     (string-join
+			       (map (lambda (x)
+				      (feta-alphabet-to-path font size x))
+				    glyphs)
+			       "\n")
+			     (ec 'g)))))
+  (set! next-horiz-adv 0.0)
+  path)
+
+(define (grob-cause offset grob)
+  "")
 
-(define (draw-line thick x1 y1 x2 y2)
-  (entity 'line ""
+(define (named-glyph font name)
+  (dispatch `(fontify ,font ,name)))
+
+(define (no-origin)
+  "")
+
+(define (oval x-radius y-radius thick is-filled)
+  (let ((x-max x-radius)
+        (x-min (- x-radius))
+        (y-max y-radius)
+        (y-min (- y-radius)))
+    (entity
+     'path ""
+     '(stroke-linejoin . "round")
+     '(stroke-linecap . "round")
+     `(fill . ,(if is-filled "currentColor" "none"))
+     `(stroke . "currentColor")
+     `(stroke-width . ,thick)
+     `(d . ,(ly:format "M~4f ~4fC~4f ~4f ~4f ~4f ~4f ~4fS~4f ~4f ~4f ~4fz"
+               x-max 0
+               x-max y-max
+               x-min y-max
+               x-min 0
+               x-max y-min
+               x-max 0)))))
+
+(define (path thick commands)
+  (define (convert-path-exps exps)
+    (if (pair? exps)
+	(let*
+	  ((head (car exps))
+	   (rest (cdr exps))
+	   (arity
+	     (cond ((memq head '(rmoveto rlineto lineto moveto)) 2)
+		   ((memq head '(rcurveto curveto)) 6)
+		   ((eq? head 'closepath) 0)
+		   (else 1)))
+	   (args (take rest arity))
+	   (svg-head (assoc-get head
+				'((rmoveto . m)
+				  (rcurveto . c)
+				  (curveto . C)
+				  (moveto . M)
+				  (lineto . L)
+				  (rlineto . l)
+				  (closepath . z))
+				"")))
+
+	  (cons (format "~a~a"
+			svg-head (number-list->point args))
+		(convert-path-exps (drop rest arity))))
+	'()))
+
+  (entity 'path ""
+	  `(stroke-width . ,thick)
 	  '(stroke-linejoin . "round")
 	  '(stroke-linecap . "round")
-	  `(stroke-width . ,thick)
-	  '(stroke . "black")
-	  ;;'(fill . "black")
-	  `(x1 . ,x1)
-	  `(y1 . ,y1)
-	  `(x2 . ,x2)
-	  `(y2 . ,y2)
-	  `(transform
-	    . ,(format #f "scale (~f, -~f)" output-scale output-scale))))
-
-;; WTF is this in every backend?
-(define (horizontal-line x1 x2 th)
-  (filledbox (- x1) (- x2 x1) (* .5 th) (* .5 th)))
-
-(define (filledbox breapth width depth height)
-  (round-filled-box breapth width depth height 0))
-
-(define (named-glyph font name)
-  (dispatch
-   `(fontify ,font ,(entity 'tspan
-			    (integer->entity
-			     (ly:font-glyph-name-to-charcode font name))))))
+	  '(stroke . "currentColor")
+	  '(fill . "none")
+	  `(d . ,(apply string-append (convert-path-exps commands)))))
 
 (define (placebox x y expr)
-  (entity 'g
-	  ;; FIXME -- JCN
-	  ;;(dispatch expr)
-	  expr
-	  `(transform . ,(format #f "translate (~f, ~f)"
-				 (* output-scale x)
-				 (- (* output-scale y))))))
-
-(define (polygon coords blot-diameter)
-  (entity 'polygon "" 
-	  '(stroke-linejoin . "round")
-	  '(stroke-linecap . "round")
-	  `(stroke-width . ,blot-diameter)
-	  '(stroke . "black")
-	  ;;'(fill . "black")
-	  `(points . ,(string-join
-		       (map offset->point (ly:list->offsets '() coords))))
-	  `(transform
-	    . ,(format #f "scale (~f, -~f)" output-scale output-scale))))
+  (if (string-null? expr)
+      ""
+      (let*
+	((normal-element (regexp-exec svg-element-regexp expr))
+	 (scaled-element (regexp-exec scaled-element-regexp expr))
+	 (scaled? (if scaled-element #t #f))
+	 (match (if scaled? scaled-element normal-element))
+	 (string1 (match:substring match 1))
+	 (string2 (match:substring match 2)))
+
+	(if scaled?
+	    (string-append string1
+			   (ly:format "translate(~4f, ~4f) " x (- y))
+			   string2
+			   "\n")
+	    (string-append string1
+			   (ly:format " transform=\"translate(~4f, ~4f)\" "
+				      x (- y))
+			   string2
+			   "\n")))))
+
+(define (polygon coords blot-diameter is-filled)
+  (entity
+   'polygon ""
+   '(stroke-linejoin . "round")
+   '(stroke-linecap . "round")
+   `(stroke-width . ,blot-diameter)
+   `(fill . ,(if is-filled "currentColor" "none"))
+   '(stroke . "currentColor")
+   `(points . ,(string-join
+		(map offset->point (ly:list->offsets '() coords))))))
+
+(define (repeat-slash width slope thickness)
+  (define (euclidean-length x y)
+    (sqrt (+ (* x x) (* y y))))
+  (let* ((x-width (euclidean-length thickness (/ thickness slope)))
+	 (height (* width slope)))
+    (entity
+      'path ""
+      '(fill . "currentColor")
+      `(d . ,(ly:format "M0 0l~4f 0 ~4f ~4f ~4f 0z"
+			x-width width (- height) (- x-width))))))
+
+(define (resetcolor)
+  "</g>\n")
+
+(define (resetrotation ang x y)
+  "</g>\n")
 
 (define (round-filled-box breapth width depth height blot-diameter)
   (entity 'rect ""
@@ -253,9 +492,32 @@
 	  `(width . ,(+ breapth width))
 	  `(height . ,(+ depth height))
 	  `(ry . ,(/ blot-diameter 2))
-	  ;;`(transform . ,(scale))))
-	  `(transform
-	    . ,(format #f "scale (~f, ~f)" output-scale output-scale))))
+	  '(fill . "currentColor")))
+
+(define (setcolor r g b)
+  (format "<g color=\"rgb(~a%, ~a%, ~a%)\">\n"
+	  (* 100 r) (* 100 g) (* 100 b)))
+
+;; rotate around given point
+(define (setrotation ang x y)
+  (ly:format "<g transform=\"rotate(~4f, ~4f, ~4f)\">\n"
+	     (- ang) x (- y)))
 
 (define (text font string)
   (dispatch `(fontify ,font ,(entity 'tspan (string->entities string)))))
+
+(define (url-link url x y)
+  (string-append
+   (eo 'a `(xlink:href . ,url))
+   (eoc 'rect
+	`(x . ,(car x))
+	`(y . ,(car y))
+	`(width . ,(- (cdr x) (car x)))
+	`(height . ,(- (cdr y) (car y)))
+	'(fill . "none")
+	'(stroke . "none")
+	'(stroke-width . "0.0"))
+   (ec 'a)))
+
+(define (utf-8-string pango-font-description string)
+  (dispatch `(fontify ,pango-font-description ,(entity 'tspan string))))