Converting a RawBoxes object to a workable expression

Question

I have manged to turn an image into a RawBoxes expression. How do I turn in back into something I can use in Graphics? In particular, I want to rotate it.

Here is a minimum working example of how I messed up. Starting with

Graphics[{Green, Triangle[]}]

I copied as bitmap into PowerPoint. Later I coped from PowerPoint into Mathematica using

a = paste;

Where "paste" is where I pasted the image.
If I do

Head[a]

it returns: RawBoxes

Expressions like

Graphics[Rotate[a, π]]

Do not work (no surprise). How do I convert an expression with Head RawBoxes back into a graphics that I can use again? Thanks

Answer 1

You can use ToExpression to turn a box expression into a normal expression. However, ToExpression doesn't work with RawBoxes, Cell or BoxData. So, the following might work for you:

rawBoxesToExpression[RawBoxes[a_]] := rawBoxesToExpression[a]
rawBoxesToExpression[Cell[BoxData[b_], ___]] := rawBoxesToExpression[b]
rawBoxesToExpression[a_] := ToExpression[a]

For example:

rawBoxesToExpression[
    RawBoxes[Cell[BoxData@GraphicsBox[{RectangleBox[{0,0}],CircleBox[{0,0}]}]]]
]

Answer 2

Thanks to those that looked at this question and tried to find a solution. I have been working at the problem and found that I can Rasterize the RawBoxes to give me an Image. I can now do ImageResize and ImageRotate

Example:

Continuing with the item that has been pasted and is called a from original post.

b = Rasterize[a];
ImageCompose[ImageRotate[b, π/2], ImageResize[b, 100]]

Hope that helps anyone who ends up with an item that has Head RawBoxes.