Re: How show Locator point and its image under a function?

*To*: mathgroup at smc.vnet.net*Subject*: [mg79880] Re: How show Locator point and its image under a function?*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Wed, 8 Aug 2007 04:43:15 -0400 (EDT)*Organization*: Uni Leipzig*References*: <f990t4$c2d$1@smc.vnet.net>*Reply-to*: kuska at informatik.uni-leipzig.de

Hi Murray, Manipulate[ Row[{Framed@Graphics[Point[pt], PlotRange -> 5], Framed@Dynamic[Graphics[Point[f[pt]], PlotRange -> 5]]}], {{pt, {-1, 1/2}}, Locator} ] may do it Regards Jens Murray Eisenberg wrote: > The following code displays a fixed point and its image under a > specified function f: > > f[{x_,y_}]:={2x+1,y+2} > Module[{pt = {-1, 0.5}}, > Row[{ > Framed@Graphics[Point[pt], PlotRange -> 5], > Framed@Graphics[Point[f[pt]], PlotRange -> 5] > }] > ] > > Now I want to have the point in the left-hand graphic to be dynamic, > controlled by a Locator, and to have its changed image under the > function to be shown in the right-hand graphic. > > The idea is something like the following (WRONG!) code: > > DynamicModule[{pts={{0,0}}}, > Row[{ > LocatorPane[Dynamic[pts],Graphics[{},PlotRange->5]], > Graphics[Dynamic[f/@pts],PlotRange->5] > }] > ] > > That code produces error messages, "1 is not a Graphics primitive or > directive", "2 is not a Graphics primitive or directive". > > How can it actually be done? >