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