Issue 3926: Add \magnifyMusic; clarify fontSize in docs.

Add \magnifyMusic; clarify fontSize in docs.

[Mark Polesky, 2014-05-24 01:35:07]

I'd like to add this \magnifyMusic command, which gives users an easy way to
enter notes at different sizes, and scales stems and beams automatically.  This
is not an obscure need; this type of notation is fairly common (at least in the
mid- to late-Romantic piano repertoire), and setting the fontSize context
property alone is insufficient, since stems and beams don't get scaled.

In the process of doing this, I ended clarifying the docs on fontSize.

https://code.google.com/p/lilypond/issues/detail?id=3926

Thanks.
- Mark

[marc, 2014-05-24 05:56:41]

https://codereview.appspot.com/96570043/diff/1/ly/music-functions-init.ly
File ly/music-functions-init.ly (right):

https://codereview.appspot.com/96570043/diff/1/ly/music-functions-init.ly#new...
ly/music-functions-init.ly:646: \override Beam.beam-thickness = #(+ 119/925 (*
mag 13/37))
Just a nitpick: I appreciate the comments about the default size and CueVoice
settings very much, but is there any reference or explanation about (+ 119/925
(* mag 13/37))?

[dak, 2014-05-24 06:33:59]

https://codereview.appspot.com/96570043/diff/1/ly/music-functions-init.ly
File ly/music-functions-init.ly (right):

https://codereview.appspot.com/96570043/diff/1/ly/music-functions-init.ly#new...
ly/music-functions-init.ly:646: \override Beam.beam-thickness = #(+ 119/925 (*
mag 13/37))
On 2014/05/24 05:56:40, marc wrote:
> Just a nitpick: I appreciate the comments about the default size and CueVoice
> settings very much, but is there any reference or explanation about (+ 119/925
> (* mag 13/37))?

Linear interpolation, two variables, two equations.  I doubt that linear
interpolation is the best choice here and one would particularly want to check
the look of big notes.  But short of other reference points...

13/37 = (0.48-0.35)/(1-0.63)

and 119/925 = (0.48 - 13/37)

[janek, 2014-05-24 13:59:54]

LGTM.
Nice addition :)

[pkx166h, 2014-05-24 15:32:41]

If this does make it in, can we have an entry in changes.tely too? Else this
gets lost in 'When it was added' to those that don't follow git.

[Mark Polesky, 2014-05-25 06:45:59]

I've uploaded a new patch set, with the following changes:

1) horizontal spacing now scales along with the resizing
2) \magnifyMusic now takes a music block, so that
   -- the temporary overrides can revert automatically
   -- the user doesn't need to manually reset it to 1
3) updated font-size description in define-grob-properties.scm
4) added regtest
5) mention \magnifyMusic in changes.tely
6) updated documentation accordingly

By the way, about the linear interpolation on the beam-thickness value, the
results look good to me across the board; here is the regtest png:
http://bit.ly/1pnVozg

Sorry I didn't think of these changes before my first upload.  Please review the
new patch.

Thanks!
- Mark

[Trevor Daniels, 2014-05-25 08:45:40]

Untested, but LGTM

Trevor

[Mark Polesky, 2014-05-26 01:27:49]

Hi all,

James has reported that this patch has somehow triggered an error in the
mozart-hrn-3.ly regtest, which makes no sense to me:
https://code.google.com/p/lilypond/issues/detail?id=3926#c3

If this in fact the case, can someone help identify the error, and how I can fix
it?  Because I have *no* idea.

Thanks.
- Mark

[Mark Polesky, 2014-06-02 22:40:03]

On 2014/05/26 01:27:49, Mark Polesky wrote:
> Hi all,
> 
> James has reported that this patch has somehow triggered an error in the
> mozart-hrn-3.ly regtest, which makes no sense to me:
> https://code.google.com/p/lilypond/issues/detail?id=3926#c3

To anyone jumping in here, the error has been cleared up:
http://code.google.com/p/lilypond/issues/detail?id=3926#c12

Patch Set 4 passes all tests.

- Mark