[Etoys] Drawing with the mouse. (third send attempt)

Jerome Peace peace_the_dreamer at yahoo.com
Tue Nov 25 23:06:43 EST 2008

Drawing with the mouse.

Note: This somehow got delivered in two pieces.
Here it is pieced back together again (maybe).
It seems some problem is breaking off the end of
this note a delivering it as a no subject email.
This is the third and final attempt to deliver it
in one piece. Hope the third times the charm.


The gui problem is that it is hard to draw good lines with a mouse.

The cursor becomes a lot more managable for drawing
when it slowly moves the pen tip.
That is, the amount of motion to move the pen a little bit
must be larger for drawing than for pointing.
If you miss while pointing that's no big deal you correct and get there.
With drawing you want control as you draw
so the pen object needs to move much slower than the cursor.

This is not too hard (for a developer) to do.
Instead of tracking cursor position
you track the total movement vector scaled down.
And add that to the target (in this case the pen objects)
current position each time.
If the cursor and pen object get too far out of sync
you just release the mouse. Move the cursor back over the pen
and start dragging it again.
The eye focuses on the moving pen.
The hands quickly learn to adjust.
The pen object can be whatever size you like.
It does not have to be "picked up".
It can just be "moved along"
(as when you drag the brown halo.)


Yours in curiosity and service, --Jerome Peace


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