Re: tablature.ly

[Marc Hohl]

Carl D. Sorensen schrieb:
> On 4/27/09 3:38 AM, "Marc Hohl" <address@hidden> wrote:
>
>   
> > Neil Puttock schrieb:
> >     
> > > 2009/4/25 Marc Hohl <address@hidden>:
> > >  
> > >       
>
>   
> > > >           (font-size (- (* num-strings 1.5) 7))
> > > >           (base-skip (cond ((= 4 num-strings) 1.55)
> > > >                            ((= 5 num-strings) 1.84)
> > > >                            ((= 6 num-strings)  2.00)
> > > >                            ((= 7 num-strings) 2.08)))
> > > >    
> > > >         
> > > Can you rework these so they're not hard-coded?
> > >  
> > >       
> > That's a bigger problem: first, I used a definition as shown in the LSR
> > and played a bit with the
> > values for base-skip, font-size and raise. Here is my first attempt:
> >
> > tabClefIV = \markup {
> >   \raise #0.7 {
> >     \override #'(font-family . sans)
> >     \bold\fontsize #-1.0
> >     \override #'(baseline-skip . 1.44)
> >     \column { "T" "A" "B" }
> >   }
> > }
> >
> > I found out that the base-line for 4 ... 7 strings follows a quadratic
> > equation:
> > base-skip = ( 0.2 * num-strings + 0.4 )**2
> > but inserting this into the definition of customTabClef didn't work, and
> > neither
> > Carl nor I could nail down the problem, so finally, I hard-coded the values.
> >
> > If you can help me with that, it would be great.
> >     
>
>
> Marc, did you get the email from Robin Bannister?  He found the problem we
> were having with customTabClef.  I had you put the baseline-skip override as
> a cons to  the property list, instead of using it as an :override function,
> and the :fontsize reset the baseline-skip.  That's why things weren't
> working right.  I think the code below works with your original quadratic:
>
> #(define-markup-command (customTabClef layout props) ()
>    (define (square x) (* x x))
>    (let* ((num-strings (length (chain-assoc-get 'stringTunings props '())))
>           (raise-value (- (* num-strings 0.4) 0.9))
>           (base-skip (square (+ (* num-strings 0.2) 0.4)))
>           (font-size (- (* num-strings 1.5) 7)))
>     (interpret-markup layout props
>      (markup #:raise raise-value #:bold
>              #:override #'(font-family . sans)
>              #:fontsize font-size
>              #:override #(cons 'baseline-skip base-skip)
>              #:column ("T" "A" "B")))))
>
>   
No, I didn't get this mail. I played around with your suggestions and the
improvements given by Neil and have now:

#(define-markup-command (customTabClef layout props tuning) (pair?)
   (define (square x) (* x x))
   (let* ((num-strings (min (max (length tuning) 4) 7))
          (font-size (- (* num-strings 1.5) 7))
          (base-skip (square (+ (* num-strings 0.2) 0.4))))
      (interpret-markup layout props
        (markup #:vcenter #:bold
                ;;#:override #'(font-family . sans)
                #:fontsize font-size
                #:override #'(cons 'baseline-skip base-skip)
                #:center-column ("T" "A" "B")))))

The raise-value calculation has gone, because I use #:vcenter, but I had 
to comment
out the font-family line, because I got an error saying "unbound 
variable: font-family"
if it is in the source. What's going wrong here?

>   
> > > Imagine a user doesn't like the default staff-space setting for
> > > TabStaff (1.5).  If they change it, none of these empirical values
> > > will work properly.
> > >
> > >       
>
> Here Neil points out the thing he's most concerned about.  It's not a
> concern about the magic numbers per se, it's that they don't change with
> staff-spacing.  In my earlier email (let me know if you didn't get it), I
> asked for his help with that problem.
>
>   
With the definition above, I inserted #(set-global-staff-size <num>)
and tried values from 10 to 100, and it worked as expected.
So the quadratic equation seems to be the right way.

Marc
> > > On a general note, I'd prefer to keep the string tunings separate from
> > > setting the clef.  To set the traditional tab clef, we have the
> > > command \clef tab, so it would be nice to be able to set the modern
> > > style using e.g. \clef moderntab without having to use a new function.
> > >  
> > >       
>
>   
> > Yes, that would be better, but I didn't manage to get the information about
> > the number of strings internally, so I used the tuning as an argument.
> > Then, to avoid setting it twice, I wrote the wrappers.
> > On the other hand, I would have to set the tuning before setting \clef
> > moderntab,
> > but this could be easily mentioned in the docs.
> >
> > As said above, any help for the base-skip problem and finding a way to
> > get the number of strings
> > without explicitly using the tuning as an argument are appreciated.
> >
> > Thank you!
> >
> > Marc
> >     
>
>
> Thank you, too, Marc!
>
> Carl
>
>
>