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REPLAY-OUTPUT-RECORD question

   Date: Thu, 30 Jun 1994 16:41-0700
   From: Gregory M Anderson <gma@BITTERROOT.apl.washington.edu>

       Date: Thu, 30 Jun 1994 11:00 PDT
       From: Scott McKay <swm@harlequin.com>

	  Date: Thu, 30 Jun 1994 09:54-0700
	  From: Gregory M Anderson <gma@bitterroot.apl.washington.edu>

	      Date: Wed, 29 Jun 1994 18:31 PDT
	      From: rdp@netcom.com (Robert Pfeiffer)

		  Date: Wed, 29 Jun 1994 16:37 PDT
		  From: Gregory M Anderson <gma@BITTERROOT.apl.washington.edu>

		  Did you ever get an answer to your question?  I've been wondering
		  the same thing, and have some thoughts, but no answers.
		  Maybe we could bash heads

	      Unfortunately, no answer has been forthcoming. I'm  still optimistic that
	      someone will provide a simple solution to this. It just can't be that
	      difficult, can it?

	  Well, I'm not sure, but I do know that I tried several unsuccessful methods.

	  I've looked at the output record contents, and I don't think that output records 
	  have enough information to be able change their color, shape, and so on.  I believe
	  the presentation is required.  So I tried erasing the output record (no problem)
	  and drawing a new one in its place (again no problem), but I can't seem to get
	  the new record to replace the old correctly in the history, and redisplays break
	  on (the new?) output record.  

	  To implement this, I stored the original output record in the objects being presented using

	  (setf (output-record object)
		  (UPDATING-OUTPUT (stream :unique-id object :cache-value (color color))
				   (present object 'type :stream stream))

	  I used the following to erase the record:

	      (erase-output-record (output-record object) stream)
	      ;; not sure whether or not to use this 
	      ;; (delete-output-record (output-record object) parent)

	  Here is where it gets fuzzy, candidates I've tried to get new the record displayed are:

	    (present object 'type:stream stream)
	    (redisplay (output-record object) stream)
	    (replay-output-record (output-record object) stream)

	  So I'm stuck.

       I would have done this to create the record

	(setf (output-record object)
	      (updating-output (stream)
		(updating-output (stream :unique-id object :cache-value (color color))
		  (present object 'type :stream stream))))

       and then simply used REDISPLAY on the cached record.

       You don't need to dink around with erasing or replaying.

   1) What is the purpose of the outer updating-output (stream)?

It's subtle, but if you reread the documentation on incremental
redisplay carefully, you'll see that we attempted to describe this.
The outermost call in UPDATING-OUTPUT is special in that it indicates
that inner output records are subject to redisplay.  Inner calls to
UPDATING-OUTPUT indicate "cache points" so that incremental redisplay
can work more efficiently.  So if you want to use REDISPLAY and have
it work well, you really need at least two levels of calls to
UPDATING-OUTPUT.  Dynamic Windows used the extra macro REDISPLAYER (I
think it was called that) to achieve the same thing.

   2) I finally deduced that replay reruns the appropriate presentation method
      but I can't figure out how to get the presentation method to redraw the
      record in the right place.  At first I didn't have the test for (output-record spot),
      and that didn't work.  So I've been trying to find out what the position is without
      success.  This is what I have so far:

   (loop for beam fixnum from 0 below (elt (array-dimensions data) 0)
      do
     (loop for sector fixnum from 0 below (elt (array-dimensions data) 1)
	   for spot = (aref data beam sector)
	do
       (setf
	   (beam spot) beam
	   (sector spot) sector
	   (output-record spot)
	      (UPDATING-OUTPUT (stream)
		 (UPDATING-OUTPUT (stream :unique-id spot :cache-value (color spot))
		   (present spot `((spot) :size ,cell-size) :stream stream :view +data-navigator-view+))))))



   (define-presentation-method present
			       (spot (type spot) stream
				     (view data-navigator-view) &key)
     ;; Note, size is a spot presentation type option, and is bound within the present
     (with-slots (beam sector color) spot
       (let ((dx (/ size 2))
	     (dy (/ size 2)))
	 (if (output-record spot)

	     (with-slots (clim-utils::left clim-utils::top clim-utils::right clim-utils::bottom) (output-record spot)
	       (multiple-value-bind (xoff yoff)
		   (convert-from-relative-to-absolute-coordinates stream (output-record-parent (output-record spot)))
		 (with-translation (stream xoff yoff)
	       (draw-rectangle* stream clim-utils::left clim-utils::top clim-utils::right clim-utils::bottom :filled t :ink color))))

	     (with-translation (stream (* beam size) (* sector size))
	       (draw-rectangle* stream (- dx) (- dy) dx dy :filled t :ink color))
	     ))))
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