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Re: display of graphics primitives

• To: mathgroup at smc.vnet.net
• Subject: [mg101275] Re: display of graphics primitives
• From: David Bailey <dave at removedbailey.co.uk>
• Date: Sun, 28 Jun 2009 23:28:23 -0400 (EDT)
• References: <h1sv5e$mbi$1@smc.vnet.net>

dsmithy wrote:
> Why do you have to place graphics primitives in the Graphics[ ]
> expression in order for them to be displayed graphically? Why doesn't,
> for example, Circle[ ] display as a graphic in StandardForm? Why must
> it be Graphics[Circle[ ]]?
> Thank you.
> 
I think the real point here is that primitives are not really much use, 
except in combination - I mean suppose you output a circle at 
coordinates (3,4) what does that mean if you don't have other 
primitives, each with their own coordinates?

If Circle[...] displayed as a circle, it would actually be a hindrance 
because you could not examine graphics expressions except in InputForm. 
It is often handy to take a graphics object g (say) and display its 
contents, e.g. by executing

g[[1]]

or

f@@g

David Bailey
http://www.dbaileyconsultancy.co.uk