output history help

[gooch@TIJERAS.SW-SW.Dialnet.Symbolics.COM (William D. Gooch)]

    Date: Mon, 17 Sep 90 16:35:22 EDT
    From: sims@starbase.MITRE.ORG (Jim Sims)

     I have an application that uses a map *much* larger than the screen, that I
    want to draw lines on. I wrote a function to do rubber-banding lines using
    dw:tracking-mouse, drawing and XORing the lines to get the rubber-band effect.
    Whenever I scroll the lines off-screen and scroll back to them, *ALL* the 
    rubber-banded segments get redrawn (UGLYYYY!!) as weel as the final (intended)
    line segments.
     I tried wrapping a (dw:with-output-recording-disabled ()) around the:
       function call
       portions of the functions doing the graphics:draw-line
       both of above,
    to no avail....
    Help anyone?
    Thanks in advance,
    jim                         (sims@starbase.mitre.org)


What you tried should have helped, but it is only part of the solution
you're looking for.  I suspect you just needed to supply the optional
stream argument to dw:with-output-recording-disabled to avoid the
awkward scrolling behavior you describe.  You will then also want to
draw the finalized line segment(s) ONCE after sketching is completed
(outside of the dw:with-output-recording-disabled body) to get the
desired line(s) to show up properly in the presence of scrolling, etc.