Re: [Plplot-devel] src/README.pages

[Maurice L. <mj...@br...>]

On Saturday, October 4, 2008 at 16:46:53 (-0700) Alan W. Irwin writes:
 > On 2008-10-04 14:04-0700 Alan W. Irwin wrote:
 > 
 > > Hi Maurice:
 > >
 > > I have just committed my first attempt (see src/README.pages) to annotate
 > > all the code fragments in our source code that affect paging and familying.
 > > Could you please give this a critical read?  I am especially interested in
 > > the open question of whether plsc->page_status should be set to DRAWING (or
 > > perhaps a new status?) for plP_state, and plP_esc.  I guess the question
 > > turns on why DRAWING is set at all for most plotting operations.  If there
 > > is some purpose to that, then my own view is the DRAWING status should also
 > > be set for at least plP_esc (which usually draws something), and perhaps
 > > plP_state as well (which AFAIK does not draw, but usually the result is status
 > > information gets written to files for file-oriented devices).
 > >
 > > To give you some background...
 > > [...]Anyhow, my plan is to deal with the repeat pladv(0) case, and once that
 > > simple test case produces valid empty page files (like it should), see
 > > whether that fix solves the example 23 issues.
 > 
 > I made the empty-page fix, and indeed that fixed the example 23 issue for
 > the pages which consisted just of text (see my recent post on the svg
 > status).  However, in my view those text-only pages (done with
 > plP_esc(PLESC_HAS_TEXT...) should have set the DRAWING status if that status
 > is to be meaningful at all.
 > 
 > What do you think about setting the DRAWING status generally for both
 > plP_esc and plP_state?

That should be ok.  The main thing to worry about are the AT_BOP and AT_EOP
values, so the pagination commands don't get confused.  Be aware there may be
some situations where you set state to DRAWING when you are actually between
pages, but that shouldn't affect anything.  I may have originally had more
plans for DRAWING but now I forget.

I read through your doc, it looks good except the warning not to mix pladv()
and plbop/pleop is perhaps a bit too strong.  One of the reasons for putting
these flags in was in fact to lessen the headache of mixing these.

I actually can't stand using pladv() or plenv() for pagination -- I always use
plbop/pleop.  Seems much more well defined that way.  pladv(0) is the
"carriage return" of printing pages (Where's the carriage?  Does it come with
horses and a princess? :)

But by keeping AT_BOP and AT_EOP status flags, throwing in an extra plbop() or
an extra pleop() when you're not sure if you've advanced to the next page
never hurts.

-- 
Maurice LeBrun