[comp.sys.mac] dragging a rectangle

lsr@Apple.COM (Larry Rosenstein) (03/01/88)

In article <1121@cpocd2.UUCP> howard@cpocd2.UUCP (Howard A. Landman) writes:
>
>This is derived from Caesar, and makes perfect sense with a 3-button mouse.
>The advantage is that, if you have a rectangle that's slightly wrong, you
>can adjust it with a single click.  If dragging is your only alternative,
>then you are forced to redraw (re-drag!) the entire rectangle, which is
>impossible if the rectangle is not all on screen.  Further, suppose you are
>trying to draw a very large rectangle that must be precisely aligned.  With
>dragging, you must zoom out to a large-scale view and hope your mousework
>is precise.  With clicking, you can zoom in to each of two opposite corners
>and do precise placement very easily.

I agree that using separate mouse buttons to set the corners of a rectangle
makes sense.  On the other hand, dragging does not have the disadvantages
you say.  

On the Mac, extending a selection is done using shift-click, and there is
nothing that says you can't adjust a rectangle in this way as well.  (This
does assume that the original anchor point of the rectangle was correct.)
It is also easy to provide mouse-sensitive handles on the rectangle, and
simply stretch it as needed.

As for drawing a large rectangle, a well-implemented program will support
automatic scrolling when the mouse leaves the window.  This is pretty common
in Mac applications.  An alternative mechanism is to allow the user to split
the window and view 2 widely-separated parts of the document at once.  Then
there is no problem in precisely aligning both corners.

In the same way that it is a mistake to equate "non-Maclike" with "wrong",
it is a mistake to assume that MacPaint or HyperCard is the way things have
to be.  The new version of MacPaint, for example, supports automatic
scrolling, and lets you modify the whole document at once.  The
"limitations" in these programs are not the result of a fundamental problem
with dragging.

>Finally, recall that Caesar and Magic were originally developed on systems
>whose displays were serial devices hanging off an RS232 port.  Imagine how
>slow and stupid dragging looks in such an environment, and the load it places

This is the same reasoning behind the original MacPaint interface.  The 128K
Mac could not support editing the entire document at once, and the user
interface was designed with that limitation in mind.  

Clearly, the assumption of RS232 lines is no longer valid in all cases.
Therefore the interface decisions should be reevaluated in light of the
current hardware environment.

>The Mac interface, while well thought out, is not the ultimate interface.

Agreed.

-- 
		 Larry Rosenstein,  Object Specialist
 Apple Computer, Inc.  20525 Mariani Ave, MS 32E  Cupertino, CA 95014
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