Re: Implement extra-offset for system positioning (issue 324810043 by address@hidden)

[david . nalesnik]

On 2017/04/28 22:49:25, thomasmorley651 wrote:
> On 2017/04/28 22:27:12, david.nalesnik wrote:
> > On 2017/04/28 22:24:57, david.nalesnik wrote:
> > > On 2017/04/28 16:15:42, david.nalesnik wrote:
> > > > On 2017/04/28 15:50:52, dak wrote:
> > > > > Does an extra-offset in X direction even make sense when the
systems are
> > > > spaced
> > > > > according to their skylines _before_ the extra-offset is
applied?
> > > >
> > > > Well, X-offset of line-break-system-details is applied in
> make-page-stencil,
> > > > too.
> > >
> > > In any case, having an extra-offset in the Y direction is
obviously much
> more
> > > useful.  Extra-offset in the X direction seems a bit superfluous,
since it's
> > > easy enough to set 'X-offset based on the left edge of the
printing space.
> >
> > Or, rather, I would imagine that the extra-offset setting for X
would be the
> > same as X-offset....
> >
> > > My
> > > original code created an extra-Y-offset, and I'm happy to go back
to this.
> > >
> > > Opinions?

> If I understand correctly the default systems X/Y-offset is calculated
> elsewhere, I like the possibility to offset those values.

Yes, but 'X-offset already acts as an offset from default values.  Try
the following example.  Any setting of 'X-offset is obviously in
relation to what's on your screen.  Set indent, short indent,
left-margin to what you like.

\version "2.19.59"

\paper {
  left-margin = 40
  indent = 30
  short-indent = 30
}

\book {
  \score {
    <<
      \new Staff <<
        \new Voice {
          \overrideProperty
Score.NonMusicalPaperColumn.line-break-system-details
            #'((X-offset . 0))
          s1*5 \break
          \overrideProperty
Score.NonMusicalPaperColumn.line-break-system-details
            #'((X-offset . 1))
          s1*5 \break
        }
        \new Voice { \repeat unfold 15 { c'4 c' c' c' } }
      >>
      \new Staff {
        \repeat unfold 15 { d'4 d' d' d' }
      }
    >>
  }
}

In contrast 'Y-offset is always an offset from the top of the page.  If
you don't set it, LilyPond calculates it.  If you set it, Lilypond uses
that instead.  extra-Y-offset will then modify whatever's in Y-offset,
default or user-specified.

So what I'm saying is that 'X-offset already acts as an offset of the
default, so an extra-X-offset is not needed.

The only reasons I can see for keeping it are: you can offset your own
setting of X-offset (why?), and you can set X and Y together.

> So I'd vote for keeping extra-offset as in your last patch-set.
> Although I'm aware David K's point is important, I think a user doing
manual
> positioning, is responsible to deal with possible problems
(collisions), too.

X-offset and Y-offset don't check for collisions.  You can put systems
on top of each other, and move them right off the page.  (That's another
attraction of "extra-offset" for a name--there are plenty of warnings
about potential collisions.)



https://codereview.appspot.com/324810043/