Re: forming continuous "trail" with Locator
- To: mathgroup at smc.vnet.net
- Subject: [mg79845] Re: forming continuous "trail" with Locator
- From: Albert <awnl at arcor.net>
- Date: Tue, 7 Aug 2007 01:21:26 -0400 (EDT)
- References: <f96jsd$qh3$1@smc.vnet.net>
Murray Eisenberg wrote:
> Is there some way in Mathematica 6 to use a Locator so as to create a
> continuous-appearing "trail" after you click and then drag the cursor
> around?
>
> Of course one could write code allowing addition of points through
> successive clicks, and then one could try to click repeatedly on
> successive points very near one another, but that could get very tedious.
>
> I mean the sort of thing one gets in drawing programs (and with the
> Mathematica 6 2D Drawing Tools).
I don't know whether and how you could do this with a Locator, but since
I have experimented with EventHandler in the last view days I came up
with this:
DynamicModule[{line = {}}, EventHandler[
Graphics[{
Dynamic[
Switch[Length[line],
0, {},
1, Point[line[[1]]],
_, Line[line]
]]
}, Frame -> True, PlotRange -> {{-1, 1}, {-1, 1}}],
{
"MouseDown" :> (line = {MousePosition["Graphics"]}),
"MouseDragged" :> (AppendTo[line, MousePosition["Graphics"]]),
"MouseUp" :> (AppendTo[line, MousePosition["Graphics"]])
}]
]
it's pretty simple and not very appealing but probably a good starting
point...
hth,
albert