Re: self-alignment-X has negligible effects on dynamics

[David Nalesnik]

On Mon, Jul 28, 2014 at 3:17 PM, Janek Warchoł <address@hidden>
wrote:

> Hi,
>
> 2014-07-28 16:13 GMT+02:00 David Nalesnik <address@hidden>:
> > In the following example, the ordinary overrides of self-alignment-X
> appear
> > to have no effect on the position pf the dynamics (or an effect I can't
> > see).  Large numbers are needed for an obvious shift.
> >
> > Is this a bug, or something I'm doing wrong?
>
> You're misusing self-alignment-X.  This feature is *not* for shifting
> stuff - it is meant for aligning particular point of an object on a
> particular point of its parent.  For example, self-alignment-X = #LEFT
> means "place this object so that its left edge (i.e. left end of
> X-extent) is horizontally aligned with its parent's left edge".  It
> doesn't mean "move stuff around". Look:
>
> {
>   % draw boxes around grobs, representing their extents
>   \override DynamicText.stencil =
>     #(make-stencil-boxer 0.03 0 ly:text-interface::print)
>   \override NoteHead.stencil =
>     #(make-stencil-boxer 0.03 0 ly:note-head::print)
>
>   \override DynamicText.self-alignment-X = #RIGHT
>   % forte's right edge is aligned with notehead's right edge
>   c'4\f
>   \override DynamicText.self-alignment-X = #LEFT
>   % forte's left edge is aligned with notehead's left edge
>   c'4\f
>   % forte's center is aligned with notehead's center
>   \override DynamicText.self-alignment-X = #CENTER
>   c'4\f
> }
>
> % see what happens when we use wider dynamics:
> {
>   % draw boxes around grobs, representing their extents
>   \override DynamicText.stencil =
>     #(make-stencil-boxer 0.03 0 ly:text-interface::print)
>   \override NoteHead.stencil =
>     #(make-stencil-boxer 0.03 0 ly:note-head::print)
>
>   \override DynamicText.self-alignment-X = #RIGHT
>   % forte's right edge is aligned with notehead's right edge
>   c'2\fff
>   \override DynamicText.self-alignment-X = #LEFT
>   % forte's left edge is aligned with notehead's left edge
>   c'\fff
> }
>
> % Using numbers outside [-1, 1] interval for alignment doesn't make
> % much sense.  What does it mean if self-alignment-X = #5 ?  What is
> % aligned to what?  It's hard to say what this means in English at all.
>
> % Of course, we could use some more alignment options.
> % That's exactly what I'm doing in issue 4022.
> % With https://code.google.com/p/lilypond/issues/detail?id=4022 ,
> % this code will produce output as in the attachment:
> {
>   % draw boxes around grobs, representing their extents
>   \override DynamicText.stencil =
>     #(make-stencil-boxer 0.03 0 ly:text-interface::print)
>   \override NoteHead.stencil =
>     #(make-stencil-boxer 0.03 0 ly:note-head::print)
>
>   \override DynamicText.self-alignment-X = #`(,RIGHT . ,LEFT)
>   % forte's right edge is aligned with notehead's left edge
>   c'2\f
>   \override DynamicText.self-alignment-X = #`(,LEFT . ,RIGHT)
>   % forte's left edge is aligned with notehead's right edge
>   c'\f
> }
>
> % Now, if you want to "move stuff around", use X-offset, not
> % self-alignment-X:
> {
>   \override DynamicText.stencil =
>     #(make-stencil-boxer 0.03 0 ly:text-interface::print)
>   \override NoteHead.stencil =
>     #(make-stencil-boxer 0.03 0 ly:note-head::print)
>
>   \override DynamicText.X-offset = -2.5
>   c'2\f
>   \override DynamicText.X-offset = 1
>   c'\f
> }
>
> % Maybe some day we'll have a more unified interface for both
> % moving stuff around and aligning it - i'm working on this - but
> % for now these are separate tasks.
>
> % Is this clearer now?


This is clearer.  Thanks!

What is potentially confusing (and you see how badly I've been confused) is
that the default setting of X-offset has changed.

I'm used to the old behavior

\override DynamicText.X-offset =
#ly:self-alignment-interface::x-aligned-on-self

gets it back.

I think that this should be made clear in the documentation, if you haven't
already done this!

Sorry for any trouble,
David