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

[Keith OHara]

On Mon, 26 Aug 2013 22:37:17 -0700, Mike Solomon <address@hidden> wrote:

> On 27 août 2013, at 07:18, "Keith OHara" <address@hidden> wrote:
>
> > (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) ?
>
> Good summary of the current state of things.  I'd argue that (2) is better.

What, then, is your argument ?

> The original function definition for \with-dimension does not need a special 
> primitive because dimension information is encoded in the stencil in parallel 
> with stencil-expressions when the markup is interpreted.

The only problem that I have heard of a special primitive is that it would be 
redundant, *if* we change a system of type (2) for building skylines.  In the 
current system, the primitive seems fine.

> The same could be true of skylines, with the caveat that skylines should only 
> be generated and used when asked for to save computation time, and otherwise 
> dimensions should be used.

How are skylines asked-for, and is it possible to know if they were asked for 
while interpreting the markup ?
{c4-\markup \whiteout \pad-to-box #(-0.5 . 9) #(-0.5 . 1.5) \concat {"Clarinet in 
B" \flat}}

The current system (1) seems more efficient at generating only the needed skylines.  We 
only need the skyline if the markup ends up in a TextScript with 'vertical-skylines set, 
as opposed to titling markup, and then stencil_traverser() works through the stencil 
expression and sees that it need not traverse through argument of \pad-to-box and need 
not trace the letters in "Clarinet in B"