On Wed, 2006-06-07 at 10:25 +0200, Han-Wen Nienhuys wrote:
> Joe Neeman schreef:
> > Did my previous mail make it to the list? I never saw it... but anyway,
> > here's an update
>
> sorry, it was on my todo list, but your patch got caught up in other stuff.
That's fine, it's just that for some reason I didn't get a copy of my
mail back so I wasn't sure if it sent properly.
>
> > make web still works and there are no detected formatting changes.
>
> Very very cool. Does this complete the optimal pagebreaking, or does the
> dynamic programming part need more work now?
I revisited the algorithm a few weeks ago, so it should be fairly clean.
There is some more functionality I would like to do though:
- tandem page/line breaking with page turns (done)
- tandem page/line breaking ignoring page turns (todo)
- tandem page/line breaking with fixed number of pages (todo)
- line, then page breaking ignoring page turns (todo)
I've tried to refactor the existing code so the other methods won't take
much code. Once I've done the last one, I can rip out the existing page
breaker. I'll post my code here before I do all that, though. It's quite
capable of peacefully coexisting with the current page breaker.
>
> > +
> > + if (scm_is_number (dy_scm))
> > + {
> > + Real dy = scm_to_double (dy_scm) * robust_scm2dir (me->get_property
> > ("stacking-dir"), DOWN);
> > + Real pos = 0;
> > + for (vsize i = 0; i < all_grobs.size (); i++)
> > + {
> > + if (all_grobs[i] == ch)
> > + return pos;
> > + if (!Hara_kiri_group_spanner::has_interface (all_grobs[i])
> > + || !Hara_kiri_group_spanner::request_suicide (all_grobs[i],
> > start, end))
> > + pos += dy;
> > + }
> > }
> > + else
>
> don't understand: aren't you missing a return? pos isn't used any further.
but it has a different value when we go through the loop again. I could
initialise pos to (-dy) and put the return at the end of the loop if it
would be clearer.
>
>
> > + vsize start_brk = VPOS;
> > + vsize end_brk = VPOS;
>
> brk -> index
sure
>
> > +
> > + /* The only time a parent is allowed to affect its children's Y-offset
> > is if
> > + it has align-interface */
> > + Grob *p = get_parent (Y_AXIS);
>
> I think you know, but this happens in some other cases as well. Mostly
> all grobs that support the positioning-done property.
I didn't know when that when I wrote the comment, though ;) I'll rewrite
the comment.
>
>
> > + if (pure && a != Y_AXIS)
> > + programming_error (_f ("tried to get pure X-offset"));
>
> don't mark programming errors as translatable. They're supposed to be
> read by programmers, not users.
sure
> > + for (vsize i = 0; i < worth.size (); i++)
> > + {
> > + Item *it = dynamic_cast<Item*> (worth[i]);
> > + if (it)
> > + {
> > + vsize col = Paper_column::get_rank (it->get_column ());
> > + important_cols.resize (max (important_cols.size (), col+1));
> > + important_cols[col] = 1;
> > + }
> > + }
>
> This looks dodgy. The resize call may introduce uninitialized data.
> Isn't it easier to sort the items-worth-living by column-rank and then
> insert False for any spans that are skipped by items-worth-living?
Probably. I'll rethink this one.
>
> Considering naming, I'd use important-column-ranks.
>
> Please use "true" iso. "1".
OK
>
> > +
> > + /* if we end up suiciding, our Y-axis-parent won't get the correct
> > + Y-extent unless we add our child to it */
> > + Grob *p = unsmob_grob (get_object ("axis-group-parent-Y"));
> > + if (p)
> > + Axis_group_interface::add_element (p, dolly);
>
> This will result in duplicate elements in the axis-group-parent-Y after
> line breaking. Isn't it possible to handle this in any of the relevant
> pure_XX functions?
I don't think so. For example, a BarNumber gets created and added to
System->object_alist_->elements. Since a mid-line BarNumber is
invisible, the original grob sucides in
Item::handle_prebroken_dependencies. By the time System->pure_extent
gets called, there are no live BarNumbers in the elements list, so none
of the pure_XX functions even get to see a BarNumber.
I suppose I could move the change into
Item::handle_prebroken_dependencies -- if we want to suicide an original
grob but the broken pieces are still potentially visible, add them to
the Y-axis-parent. Would that be better?
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