On Fri, 1 Feb 2002, Tomas Frydrych wrote:
>
> Hi Martin,
>
> > I got the idea for doing this is a sane way after tracing through the
> > code that caused list elements to flash. There was code in
> > fv_View::_generalUpdate to update every field in the document by
> > scanning every run in the document after every keypress. There were
> > some good ideas in this code, especially the "isLayoutDependent()"
> > method on field runs. I changed the name of this to
> > "needsFrequentUpdates()" and put another bool in fl_BlockLayout
> > "hasUpdatableField()". This is (un)set during a format if there is a
> > field run with "needsFrequentUpdates()" true. Then during the
> > background redraw (which happens every 0.5 seconds) blocks with
> > "HasUpdatableField()" set have a recalculateFields() done on them. If
> > the field width changes on the recalculation, the block is reformated.
> > Anyway it all works rather nicely and scales reasonablly well.
> Sounds very nice; I wish thought of it myself :-).
>
> > Fields like "Current Time" and "Word Count" have
> > "needsFrequentUpdates()" set true. Fields like "date", "page number"
> > and "liast label" do not.
> Except the "page number" field is layout dependent and should
> update if as a result of layout changes it moves onto a different
> page. The reason I added the layout rescanning code was that
> fields such as "page reference" would not reliably update. I think
> what we still need is "updateFields" method in
> ap_EditMethods.cpp, that the user could call to update all fields in
> the document, and would be automatically called (or better, based
> on preference settings) before printing.
>
It is taken care of in printing automatically because an entire layout
structure is created with the printer graphics context in
place. Everything is updated and correctly formatted. It's a "snapshot" of
the current layout. I wasn't sure if "page number" field should be a
"frequently" updated field or not. I guess I didn't do it because then all
the headers and footers fields with page numbers would be redrawn every
0.5 seconds.
I'm not quite sure what to do about this.
Cheers
Martin
