[comp.sys.mac.system] Real-time scrolling

lsr@Apple.COM (Larry Rosenstein) (06/29/91)

In article <D2150035.i0jd5d@outpost.UUCP> peirce@outpost.UUCP (Michael Peirce) writes:
>
>The problem with tracking the thumb in real time on the Mac is 
>supporting those ever popular 68000 based machines.  No way are 
>you going to be able to smoothly keep the window in sync with 
>the thumb.

That's true, but on a Mac IIx or a Mac IIfx it works pretty nicely.  The
reason is that most of the time the scroll increment is small and most apps
are optimized for that case.

To see for yourself, install the enclosed system extension.  After
installing it, holding down the command key while clicking in the thumb will
let you scroll in real time.  Also, command-click in the gray paging areas
will jump the thumb to the click point, at which time you can drag it around
for fine-tuning.

CAVEAT: I haven't tested this out much, although unless you activate it it
should be pretty stable.  I've found that it doesn't work well in certain
cases.  

For example, in the Finder if the window is only slightly smaller
than the size necessary to display everything, then the real-time scrolling
becomes jerky because the range over which the window can scroll is much
smaller than the range over which the thumb can be dragged.  In MPW there's
a lot of flashing because MPW repaints the whole window when you use the
thumb. 

Enjoy,

Larry


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-- 
Larry Rosenstein, Apple Computer, Inc.

lsr@apple.com
(or AppleLink: Rosenstein1)