Re: How many use the diagram tree?

["James K. Lowden" <jklowden schemamania org>]

On Mon, 11 Aug 2003 10:35:33 -0500, Lars Clausen <lrclause@cs.uiuc.edu>
wrote:
> On 10 Aug 2003, James K. Lowden wrote:
> > <rant> One thing I've never understood is Visio's facination with
> > handles.  Why?  Any 14-year-old knows a line consists of an infinite
> > set of points.  What's the purpose of picking out some few as more
> > significant than the rest?  ... </rant>
> 
> Nice rant:)  

	:-)

> The only reason I see for the handles is to
> have a way to attach 'prettily', i.e. exactly in the middle or exactly
> at the corner.  What's ERwin do there?

Hi, Lars.  Sorry for the delay.  I was in India.  

ERwin has two modes.  When you draw a line from one object to another, it
automatically attaches at the centerpoint of the line.  When you draw a
second line from the same object, it positions both lines at a
predetermined distance either side of the centerpoint.  Three gets on one
on the centerpoint and one on either side, and so on.  Neat and
convenient, as a default.  Maybe all lines are an odd number of pixels; I
never counted.  

The second mode comes into play when you adjust a line from its default
position.  A line "knows" when it's been adjusted (and can be set back to
the default).  Once you touch a line to reposition it, it stays where you
put it, insofar as the attachment position is concerned.  (One fly in the
ointment is that the autoposition algorithm ignores manually positioned
lines, so one learns to pull any such lines well clear of the
centerpoint.)  Obviously, as you move objects around, the lines remain
attached, whether positioned automatically or manually.  Sometimes that
leads to some ugly routes for lines stuck on the "wrong" side, and in such
cases it's usually easiest to reset the line to "autodraw" (ERwin usually
seems to find the shortest path) and then re-adjust as necessary.  

> Removing handles would require better feedback of hitting objects.  A
> 'highlight' function with sensible defaults would help for that and a
> number of other feedbacks.

To attach a line in ERwin, you just drag the endpoint on top of the
target.  I've never missed the lack of feedback, and I think my hit ratio
is in the range of 5 nines.  Of course, that approach does lack a certain
pin-the-tail-on-the-donkey excitement.  ;-)

As far as "other feedbacks" go, perhaps the shape's entire outline could
change color, instead of just the connection point, until you release the
mouse button?  

Regards, 

--jkl