Re: How many use the diagram tree?

[Lars Clausen <lrclause cs uiuc edu>]

On 7 Sep 2003, James K. Lowden wrote:
> 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.  

You lucky bastard:)

> 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.

Interesting setup.  0.92 has a similar system of two modes for the
autorouting, so from the lines point of view, it's easy.  Then there's the
problem of how the shapes figure out where to place the connections.  

>> 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.  ;-)

I would like to have that in Dia, too.  5 Dia Points[tm] to whoever makes a
good implementation:)

> 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?  

Yes, I was planning to add in 0.93 functionality to highlight an object,
much like you see it in many computer games.  I think it would be an easy
thing to add in the interactive renderers.

-Lars

-- 
Lars Clausen (http://shasta.cs.uiuc.edu/~lrclause)| HĂ„rdgrim of Numenor
"I do not agree with a word that you say, but I   |----------------------------
will defend to the death your right to say it."   | Where are we going, and
    --Evelyn Beatrice Hall paraphrasing Voltaire  | what's with the handbasket?