Re: C++ question:

[Knut Petersen]

Am 20.01.2017 um 13:35 schrieb David Kastrup:
> Knut Petersen <address@hidden> writes:
>
> > Hi David!
> > > Uh what?
> > >
> > > If you want to change the dimensions of a stencil copy, you can just do
> > >
> > > Stencil wd0 = orig;
> > > wd0.set_empty (false);
> > I use the following code to emit hyphens (stencil ds) and whiteout boxes 
> > (stencil ws)
> > in lyric-hyphen.cc:
> >
> >    Stencil total;
> >    for (int i = 0; i < hyphens; i++)
> >      { // ok
> >        Stencil ds = dash_stencil;
> >        ds.translate_axis (span_points[LEFT] + start_space +
> >                           i * (dash_period + dash_length), X_AXIS);
> >        total.add_stencil (ds);
> >        if (whiteout > 0.0 )
> >          {
> >            Box wb (Interval (0, dash_length + 2 * whiteout * lt),
> >                    Interval (h - whiteout * lt, h + th + whiteout * lt));
> >            Stencil ws (Lookup::round_filled_box (wb, 0.8 * lt));
> >            ws = ws.in_color (1.0, 0.0, 0.0);
> >            ws.translate_axis (span_points[LEFT] + start_space + i * (dash_period
> >                               + dash_length) - whiteout * lt, X_AXIS);
> >            ws.set_empty(false); // <== Does not help against collision detection
> >            total.add_stencil (ws);
> >          }
> >      }
> >
> > As you can see in the attached jpgs, a collision of the whiteout box moves the 
> > last lyric line down.
> > set_empty(true) nor anything else I tried does change anything.
> Uh, you set the dimensions to 0,0 _after_ moving the thing to its place.
> That would make the remaining point stick out seriously wide of the
> actual glyph.  Maybe move the set_empty before the translate_axis?

Not even the following code shows any improvement:

  Stencil total;
  for (int i = 0; i < hyphens; i++)
    {
      Stencil ds = dash_stencil;
      ds.translate_axis (span_points[LEFT] + start_space +
                         i * (dash_period + dash_length), X_AXIS);
      total.add_stencil (ds);
      if (whiteout > 0.0 )
        {
          Box wb (Interval (0, dash_length + 2 * whiteout * lt),
                  Interval (h - whiteout * lt, h + th + whiteout * lt));
          Stencil ws;
          ws.set_empty(false);
          ws = (Lookup::round_filled_box (wb, 0.8 * lt));
          ws.set_empty(false);
          ws = ws.in_color (1.0, 0.0, 0.0);
          ws.translate_axis (span_points[LEFT] + start_space + i * (dash_period
                             + dash_length) - whiteout * lt, X_AXIS);
          ws.set_empty(false);
          total.add_stencil (ws);
          total.set_empty(false);
        }
    }

  total.translate_axis (-me->relative_coordinate (common, X_AXIS), X_AXIS);
  total.set_empty(false);
  return total.smobbed_copy ();
}

Knut