"clickable" objects in scrolling windows

[Andrew L. M. Shalit <alms>]

   From: boyd@jpl-devvax.jpl.nasa.gov (Bonnie L. Boyd)
   Date: Tue, 5 Mar 91 17:13:51 PDT
   X-Mailer: ELM [version 2.2 PL14]




   Hi, i hope someone can help me with this problem:

   I'm using allegro common lisp (version 1.3.2) and its interface to
   QuickDraw routines to create selectable button objects and scrolling
   text objects that can be placed upon a scrolling window. Although
   allegro v. 1.3.1 had such objects, in this current version of allegro,
   its old scrolling window will not accept "click-able" user interface
   objects such as buttons and scrolling texts.

This isn't correct.  You shouldn't have to reimplement everything.

Your problems might be due to a misunderstanding of how scrolling
windows work.  There are three things to think about in a scrolling
window: There is a the window, there is the scrollable view, and there
is the scroll-bars.  The scroll-bars and the scrollable view are
both in the window.  However, you don't want to add more items to
the window.  You want to add your items to the scrollable view.
That way, when the scrollable view is scrolled, your items will move.

This structure is needed to prevent the scroll-bars from moving when
the item is scrolled.

   -andrew