Re: Improve implementation of dashed slurs

[Joe Neeman]

On Fri, 2009-04-17 at 22:17 -0600, Carl D. Sorensen wrote:
> 
> 
> On 4/17/09 1:47 PM, "address@hidden" <address@hidden> wrote:
> 
> > Very pretty slurs!
> 
> Thanks!
> 
> > 
> > 
> > http://codereview.appspot.com/41099/diff/1021/59
> > File lily/bezier.cc (right):
> > 
> > http://codereview.appspot.com/41099/diff/1021/59#newcode275
> > Line 275: Bezier::subdivide (Real t, Bezier &left_part, Bezier
> > &right_part)
> > We only use references if they are const (for clarity), so please change
> > the arguments to pointers. Also, this function can be marked as const.
> 
> So, if I understand right, you want
> Bezier::subdivide (Real t, Bezier *left_part, Bezier *right_part) const

Yep

> 
> and then in the code, instead of
> 
> left_part.control_[i]=
> 
> I do
> 
> *left_part.control_[i]=
> 
> Is this right?

This should be "left_part->control_[i]=". It is also correct to write
"(*left_part).control_[i]=", but the former is preferable.

> > http://codereview.appspot.com/41099/diff/1021/62#newcode347
> > Line 347: SCM dash_details)
> > Since dash_details seems to just be a list of Reals, perhaps its better
> > to have a vector<Real> const& (with an empty vector to signify a solid
> > slur).
> 
> No, dash_details is a list of lists of floating point numbers.  There is one
> list for each segment of the slur; there can be as many segments as the user
> desires.

Ah, OK. I won't insist, but I think it might be nicer to make this more
statically typed. For example:
typedef struct {
  Real t_min;
  Real t_max;
  Real dash_fraction;
  Real dash_period;
} Dash_definition;
and then make the argument a vector<Dash_definition>. Since C++ is a
statically typed language, I think it's nicer to make use of that static
typing and do the type checking/conversion for SCM variables as early as
possible instead of propagating them through the C++ code.

Joe