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Re: Controlling the Appearance of Locators in Manipulate

  • To: mathgroup at smc.vnet.net
  • Subject: [mg79115] Re: [mg79089] Controlling the Appearance of Locators in Manipulate
  • From: Murray Eisenberg <murray at math.umass.edu>
  • Date: Thu, 19 Jul 2007 03:25:49 -0400 (EDT)
  • Organization: Mathematics & Statistics, Univ. of Mass./Amherst
  • References: <200707180658.CAA04517@smc.vnet.net>
  • Reply-to: murray at math.umass.edu

Not an answer, but a comment: "Appearance" seems to be an especially 
poorly documented primitives in Mathematica 6.0.  Obviously part of the 
problem is that it can have so many different kinds of values in 
different situations.

(A similar thing is true about "Style".  At least there is a list of 
common admissible values given, but indeed they are only, in the 
phraseology of the Style home page, just lists of "a few common explicit 
options" and "a few common named styles".)

Sometimes, starting at Options[name] helps for such things, but here it 
doesn't seem to help much.  What seems to be missing is a more general 
mechanism for determining the legal kinds of values for an "overloaded" 
option such as Appearance in a particular context. I say "overloaded" in 
the sense that the same option may be used in different functions, where 
different values may be relevant.

David Park wrote:
> I'm still trying to learn the elements of 6.0. Here is a Manipulate 
> statement I wrote to illustrate the functionality of ScalingTransform. One 
> can adjust the x and y scaling about an arbitrary center of an arbitrary 
> quadralateral. The initial display has the identity scaling so one must move 
> the sliders to see the scaled quadralateral. Then the vertices can be moved 
> with the locators and this will expose the center of the scaling, which can 
> then also be moved....[code snipped]...
> 
> I wanted to change the appearance of the locators to points. But once I 
> change the appearance for one of the Locators, then that appearance applies 
> to all Locators. How could I control the appearance of each Locator 
> individually? Specifically, how could I change the color of the last center 
> Locator to Red while keeping the rest of them Black?

-- 
Murray Eisenberg                     murray at math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower      phone 413 549-1020 (H)
University of Massachusetts                413 545-2859 (W)
710 North Pleasant Street            fax   413 545-1801
Amherst, MA 01003-9305


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