Re: Can a Locator be Made to Track a Curve?
- To: mathgroup at smc.vnet.net
- Subject: [mg120792] Re: Can a Locator be Made to Track a Curve?
- From: DrMajorBob <btreat1 at austin.rr.com>
- Date: Wed, 10 Aug 2011 06:46:59 -0400 (EDT)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- References: <201108060612.CAA13010@smc.vnet.net>
- Reply-to: drmajorbob at yahoo.com
I don't see anything unexpected, using the code below. The function derivative is high (relative to the scale of the plot) in that region, so {x, f@x} is sensitive to the value of x, and hence, it's difficult to place the cursor precisely where you want it. I never saw it get "stuck". Bobby On Tue, 09 Aug 2011 06:19:45 -0500, E. Martin-Serrano <eMartinSerrano at telefonica.net> wrote: > Try this slightly modified version and see what happens for 0<x< 1 > > locator = Graphics[{Red, Disk[{0, 0}, Offset[3]], Black, Circle[{0, > 0}, > Offset[3]], Circle[{0, 0}, Offset[6]] }, ImageSize -> 30]; > > f[x_] := Sin[x] E^-x; > g[{x_, _}] := {x, f@x} > pt = {0, 0}; > LocatorPane[Dynamic[pt, (pt = g@#) &], Plot[f[x], {x, 0, 2 Pi}], > Appearance > -> locator] > > The locator tends to go out of control for 0<x< 1. I observed this, > say, > abnormal behavior for all versions posted; after changing f[x_] := > Sin[x] > to f[x_] := Sin[x] E^-x. It seems the problem is not related to the > inclusion of the tailored locator (works the same for the built in one). > Sometimes the locator tends to jump or get stuck within 0<x< 1 range. > > > -----Mensaje original----- > De: DrMajorBob [mailto:btreat1 at austin.rr.com] > Enviado el: lunes, 08 de agosto de 2011 10:21 > Para: mathgroup at smc.vnet.net > Asunto: Re: Can a Locator be Made to Track a Curve? > > A bit simpler, I think, is: > > f[x_] := Sin[x]; > g[{x_, _}] := {x, f@x} > pt = {0, 0}; > LocatorPane[Dynamic[pt, (pt = g@#) &], Plot[Sin[x], {x, 0, 2 Pi}]] > > Bobby > > On Sun, 07 Aug 2011 05:14:52 -0500, Heike Gramberg > <heike.gramberg at gmail.com> wrote: > >> You could do something like >> >> f[x_] := Sin[x]; >> pt = {0, 0}; >> LocatorPane[Dynamic[pt, (pt[[1]] = #[[1]]; pt[[2]] = f[#[[1]]]) &], >> Plot[Sin[x], {x, 0, 2 Pi}]] >> >> Heike >> >> On 6 Aug 2011, at 08:12, Gregory Lypny wrote: >> >>> Hello everyone, >>> >>> Can a locator be constrained so that it tracks a curve? >>> >>> Regards, >>> >>> Gregory >>> >> >> > > > -- > DrMajorBob at yahoo.com > > -- DrMajorBob at yahoo.com
- References:
- Can a Locator be Made to Track a Curve?
- From: Gregory Lypny <gregory.lypny@videotron.ca>
- Can a Locator be Made to Track a Curve?