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Is there a way to force Mathematica to convert an already rendered Graphic to the simplified Directive form of that Graphic.

Background: I am currently editing Graphics using Drawing Tools and then calling InputForm[gr], but this often doesn't work well because the output of InputForm are much larger then the original input.

For example I am looking for the following code

gr = Graphics[{Red, Circle[]}];

To output the simplest form possible.

For example HoldForm[InputForm[gr]] could print Graphics[{Red, Circle[]}] or Graphics[{Red, Circle[0,0]}].

EDIT: There are a lot of Graphic directives listed in the docs, so there probably isn't a direct answer, but simply answers that get closer to respecting the original input. The best technique IMO would somehow create a trained function which evolves based on the version of Mathematica that you are currently using. Obviously manual transformation are less then ideal.

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closed as unclear what you're asking by Liam, ssch, Leonid Shifrin, Artes, m_goldberg Sep 14 '13 at 0:59

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question.If this question can be reworded to fit the rules in the help center, please edit the question.

I'm not sure what you're asking, can you clarify? Do you just want to get Red instead of RGBColor[1,0,0]? Can you show what InputForm shows you and point out specifically what you don't like about it? – Szabolcs Sep 10 '13 at 23:26
@Szabolcs small typo. It should have said InputForm[gr]. Halirutan and I have been discussing this in the chat room. Ultimately I would like the output of InputForm[gr] to be a close to the original input as possible. Currently the ouptut is Graphics[{RGBColor[1, 0, 0], Circle[{0, 0}]}] instead of Graphics[{Red, Circle[]}]. There are a lot of Graphic directives listed in the docs, so there probably isn't a direct answer, but simply answers that get closer to respecting the original input. – Liam Sep 10 '13 at 23:32
It's probably just a typo, but Graphics[{Red, Circle[0, 0]}] is invalid syntax. – m_goldberg Sep 11 '13 at 0:34
I would like to nominate this question for reopening. Even though it is a bit misguided I think it is interesting. – Mr.Wizard Jan 15 '15 at 15:10
up vote 4 down vote accepted

This strikes me as a flawed question (sorry) as you are converting between forms that are not entirely equivalent. I mean that for example there are a number of different sets of named colors, and you cannot ultimately know what set may have been used to create the Graphics therefore you cannot "put Humpty Dumpty together again."

Nevertheless if we are going to attempt this I think I can give cleaner code that what halirutan provided:

rules = MakeExpression@# /. _[x_] :> #2 :> x & @@@ ColorData["Legacy", "ColorRules"];
AppendTo[rules, Circle[] :> Circle[]];


gr = Graphics[{Red, Circle[]}];
HoldForm @@ {InputForm@gr} /. rules
Graphics[{Red, Circle[]}]
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This isn't an attempt to retrieve the original input, but instead have a cleaner more pleasant output to look at. I have modified your code slightly. Is there a way to get a list of shapes that have default parameters? I am currently manually listing them like the following Map[(#[] :> #[]) &, {Circle, Rectangle, Disk,Cylinder, Sphere, Cone, Tube}] – Liam Sep 14 '13 at 18:36
@Liam That makes more sense to me now; thanks. Regarding shapes, no, not that I am aware of; I'd do it the same way you are. – Mr.Wizard Sep 15 '13 at 17:14

As discussed in chat, one way to revert the colors to their names is to use ColorData to create a list of named colors and inject them back into your held graphics:

rules = Cases[
   MakeExpression[#] /.
      HoldComplete[expr_] :> (HoldPattern[Evaluate[expr]] :> expr) & /@
     ColorData["HTML", "ColorFunction"][[3, 1]],
   HoldPattern[Verbatim[HoldPattern][_RGBColor] :> _]];

gr = Graphics[{Red, Circle[]}];
With[{expr = InputForm[gr]},
 HoldForm[expr] /. rules
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