Re: Re: Graphics Question

*To*: mathgroup at smc.vnet.net*Subject*: [mg35469] Re: [mg35459] Re: Graphics Question*From*: jmt <jmt at agat.net>*Date*: Sun, 14 Jul 2002 06:19:42 -0400 (EDT)*References*: <agjj0o$24v$1@smc.vnet.net> <agm3v1$53i$1@smc.vnet.net> <200207130748.DAA08580@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

I would like to add : Some interactivity can be achieved using java graphics capabilities, consequently should be OS independant. On Saturday 13 July 2002 09:48, AES wrote: > > > Is there any way to create interactive graphics? It seems all > > > animation is done by precalculating frames. For some things this is > > > ok, but it would be nice to be able to dynamically alter a graphic, and > > > even better make changes based on input of various sorts. Perhaps an > > > add-on package exists? Or perhaps in an upcoming version? > > I believe this is a fair and significant question to pose -- and > unfortunately a difficult one for Mathematica to answer. > > What this poster would like, and so would I, is the ability to add a new > point or object, or a succession of new objects, to an existing > on-screen plot, without redrawing the whole plot -- for example, to see > a curve "crawl" across a plot without calculating and storing a whole > bunch of nearly identical images, or to let a user interactively move an > object in a plot with the mouse and see other parts of the plot change > appropriately in a fluid and instantaneous fashion. We'd like this to > be fast, and also very simple to program (an Mathematica command > "ShowAdded[Graphics[--]]" that adds a new graphics element to a plot > that's already on screen, along with an "Erase[Graphics]" command.) > > Unfortunately, as I understand it, Mathematica graphics just aren't set > up to function in this fashion. These capabilities can be simulated to > some extent, if the computer is fast enough, but I believe the > fundamental architecture of Mathematica is based on formulating, then > displaying one complete PostScript graphic at a time. The idea of > adding new points to an existing, already on screen plot, without > redrawing the whole image, is not part of the underlying structure. > > I don't fault Mathematica for this; It may not be possible to do > otherwise in a multi-platform package. Adding to a display already on > screen I believe implies having access to system-level or "screen-level" > aspects of the computer, and these are greatly different from computer > to computer. > > Comments from more knowledgeable people obviously welcomed . . . > > [Incidentally, is there an "Erase" command in Mathematica now? Can I > program > > myGraphic =Graphics[bunch-of-graphics-stuff] > > Show[myGraphic] > > Erase[myGraphic, one-piece-of-this-stuff] > > ReShow[myGraphic] > > ???]

**References**:**Re: Graphics Question***From:*AES <siegman@stanford.edu>