How to notify user as to acceptable drop targets?

Martin McClure martin at
Mon Apr 15 21:39:21 UTC 2002

At 12:52 PM -0700 4/15/02, Ned Konz wrote:
>On Monday 15 April 2002 12:18 pm, Martin McClure wrote:
>>  To make this work, the d'n'd framework has to send a message to
>>  each potential target as you pass over it to see if it would accept
>>  the dragged object. If this slows things down too much, you could
>>  wait until the user has paused over a potential target for a few
>>  hundred milliseconds before sending the message.
>How do you feel about cursor highlighting? That's easy to do.

I don't like it as well as the target highlighting, but it's better 
than no highlighting.

I think my preference for target highlighting over cursor 
highlighting stems from my instincts about the role represented by 
the cursor. The cursor is my avatar, if you will, and through it I 
'speak' my commands to everything else on the screen. And I'm not 
telling the screen object whether it should accept the drop, it's 
telling me whether it is willing to. By sending my 'avatar' over a 
target I'm asking a question of the target. It seems more direct to 
have the target answer the question to me directly rather than 
whisper it to my avatar and then have my avatar tell me. Since it's 
the target that is 'speaking' so it seems that the object should 
highlight, not the cursor.

In general I guess I don't like cursor shape-change feedback except 
where the change either echoes something I've commanded or represents 
a change in my general ability to control things.

An example of the former is the little plus sign that's attached to 
the cursor when copying a file by option-dragging in the Mac Finder 
or by control-dragging in the Windows explorer. I like that because 
it seems reasonable for my avatar to say to me "Yep, I'm telling it 
to copy, just like you told me to."

An example of the latter is one of the many variants of the wait 
cursor found on various systems. I like those because they are 
basically my avatar saying to me "I'm asleep now, so all of your 
commands will be ignored until I wake up again."

Now what I'd *really* like (in addition) is an interface to a 
force-feedback mouse, where the mouse would physically resist 
dragging an object to a place it wasn't wanted, and would physically 
encourage snapping to an object where the drop would be accepted. A 
friend of mine has a force-feedback mouse that puts force feedback 
into the Windows GUI. The little bumps you feel as the cursor travels 
over the edges of buttons, menu items, and windows are subtle but 
really make a difference. It's suddenly easier to hit the menu item 
you wanted and harder to accidentally slip onto the menu item below. 
If they had a Mac driver for it I'd have one in an instant... 
(anybody done any force-feedback stuff in Squeak? I don't remember 
hearing about any.)


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