Re: Graphics and DisplayFunction

*To*: mathgroup at smc.vnet.net*Subject*: [mg98250] Re: Graphics and DisplayFunction*From*: David Bailey <dave at removedbailey.co.uk>*Date*: Fri, 3 Apr 2009 04:39:31 -0500 (EST)*References*: <gqsn9m$3tr$1@smc.vnet.net> <gr21l6$lq8$1@smc.vnet.net>

replicatorzed at gmail.com wrote: > Thanks for the answer Szabolcs, > > Ok, so if I understand it correctly then by using explicit > DisplayFunctions, I display the *thing*, that is the side effect of > the actual function. Obviously only things that are enclosed in Show > can be thus displayed with DisplayFunctions, and - however it's just a > guess - the various plot functions all utilize an internal Show which > encloses their internal graphics. Thus - secondarily - DisplayFunction > can be used with plotting functions as well. But then I simply don't > understand why DisplayFunction is an option for Graphics? Neither > I would forget about the DisplayFunction option - it is more or less obsolete. Just think of graphics as output - just like numbers or equations. If you do a calculation, and then as the last step generate a graphical output (either explicitly with Graphics, or indirectly using Plot (say), then providing you don't terminate that command with a semicolon, you will get your graphical output, for example: xx = 10; yy = 20; Graphics[{Line[{{-xx/2, 0}, {xx/2, 0}}], Line[{{0, -yy/2}, {0, yy/2}}]}] If, however, you want to go on and calculate something else (or make another graph), simply print your graphical output (again, exactly as you would for text): xx = 10; yy = 20; Print[Graphics[{Line[{{-xx/2, 0}, {xx/2, 0}}], Line[{{0, -yy/2}, {0, yy/2}}]}]]; Print["Something else ",Sqrt[xx]];