- (slash-stencil
- (ly:make-stencil
- `(draw-line
- ,thickness
- ,(car num-x) ,(- (interval-center num-y) dy)
- ,(cdr num-x) ,(+ (interval-center num-y) dy))
- num-x num-y
- )))
-
- (ly:stencil-add number-stencil
- (cond
- ((= num 5) (ly:stencil-translate slash-stencil
- ;;(cons (* mag -0.05) (* mag 0.42))
- (cons (* mag -0.00) (* mag -0.07))
-
- ))
- ((= num 7) (ly:stencil-translate slash-stencil
- ;;(cons (* mag -0.05) (* mag 0.42))
- (cons (* mag -0.00) (* mag -0.15))
-
- ))
-
- (else slash-stencil)))
- ))
+ (is-sane (and (interval-sane? num-x) (interval-sane? num-y)))
+
+ (slash-stencil
+ (if is-sane
+ (ly:make-stencil
+ `(draw-line
+ ,thickness
+ ,(car num-x) ,(- (interval-center num-y) dy)
+ ,(cdr num-x) ,(+ (interval-center num-y) dy))
+ num-x num-y)
+ #f)))
+
+ (set! slash-stencil
+ (cond
+ ((not (ly:stencil? slash-stencil)) #f)
+ ((= num 5) (ly:stencil-translate slash-stencil
+ ;;(cons (* mag -0.05) (* mag 0.42))
+ (cons (* mag -0.00) (* mag -0.07))
+
+ ))
+ ((= num 7) (ly:stencil-translate slash-stencil
+ ;;(cons (* mag -0.05) (* mag 0.42))
+ (cons (* mag -0.00) (* mag -0.15))
+
+ ))
+
+ (else slash-stencil)))
+
+ (if slash-stencil
+ (set! number-stencil
+ (ly:stencil-add number-stencil slash-stencil))
+
+ (ly:warning "invalid number for slashed digit ~a" num))
+
+
+ number-stencil))