Re: rewrite Self_alignment_interface (issue 7768043)

[address@hidden]

On 1 avr. 2013, at 14:13, Janek Warchoł <address@hidden> wrote:

> Hi all,
> 
> On Mon, Apr 1, 2013 at 7:52 AM,  <address@hidden> wrote:
>> I'd recommend adding a sort of padding property to the
>> self-alignment-interface to get it completely there.
>> That is, imagine that we right align to a grob and we want
>> to be padded by 0.1  We should be able to do that.
>> That'd allow self-alignment-interface to be used
>> for grobs like InstrumentName.
> 
> I think that this should be done by manipulating extents:
> if i want an InstrumentName to be "horizontally-aligned-
> with-padding", i add desired padding value to its X-extent,
> and voilà!  LilyPond thinks that InstrumentName is slightly bigger,
> aligns it as if it was slightly bigger, and thus it ends up padded.
> What do you think?

X-extent is used in many things other than self alignment positioning, so u 
don't want to change extents. Every positioning in LilyPond has some notion of 
padding save this interface. It would be a good addition, but could easily be 
in a follow-up patch.

> 
> As for chain_offset_callback, i've tried it (see attached patch), but
> i get a strange error:
> 
> Processing `input/regression/add-stem-support.ly'
> Parsing...
> Interpreting music...
> Preprocessing graphical objects...ERROR:
> In procedure ly:self-alignment-interface::x-align-grob:
> ERROR: Wrong number of arguments to
> #<primitive-procedure ly:self-alignment-interface::x-align-grob>
> 
> quite frankly, i don't know what's wrong.
> I've looked at other uses of chain_offset_callback
> and it seems that i've written my code correctly.
> 

I'll look into it when I get home.

> PS i'll look into Ambitus extent later - right now i'm getting some
> unexpected regressions after doing some additional modifications.
> <0001-use-chain-offsets-instead-of-setting-properties.patch>