Re: Adds dimension stencil command to correct with-dimension (issue 12957047)

[Keith OHara]

On Mon, 26 Aug 2013 02:11:28 -0700, Mike Solomon <address@hidden> wrote:

> I think that if we can devise a better system, the creation of a new stencil 
> primitive is unnecessary.  If we agree that we should implement a system where 
> stencils are carriers of their own skylines, then we should fix this bug using 
> that system.

In any system of building skylines from markup, we want to regain the 
spacing-control that we had with
  \with-dimensions #(0 . 1) #(0 . 1) "text"
and maybe we might have in the future
  \with-shape {/* shape for purposes of spacing around music */} "text"

Maybe someday both of these will be implemented using a skyline-generator and 
skyline-remover
  \combine
    \transparent \make-shape {/* shape for spacing */}
    \no-skyline "text"

In any case we need a way to omit or ignore the usual skyline from some markup.


(1) At the moment, the stencil expressions are assembled first, when markup is 
interpreted, and then stencil_traverser() reads the stencil expression to 
figure the skylines.  So long as that approach remains in place we need some 
sign in the stencil expression to be read by stencil_traverser() telling it to 
omit the usual skyline around part of the stencil.  (I could re-use 
'delay-stencil-evaluation, but think a new primitive is wiser.)


(2) If someday the skylines are assembled in parallel with stencil-expressions when the 
markup is interpreted, then \with-dimensions or \no-skyline could simply throw away the 
skyline it built for "text" (in the examples above) and there is no need for a 
'with-dimensions' primitive.  (There would still be primitives that move markup like 
'translate-stencil' for things like \concat {B\flat}.)


Are systems organized as in (2) better systems than the one we have organized 
as in (1) ?