Saving plot annotations

Yesterday, while adding some timing plots to the "Optimally picking one element from each list" question I was once more remembered of a mathgroup posting I did a couple of years ago ("Keeping plot annotations after regenerating a plot").

I was happily annotating my plots (manually) when I thought that some axis labels would be nice. Problem is, regenerating the plots with the axis labels in place will destroy your manual annotations.

It appears you can find user additions in a plot named pic here: Rest[pic[[1, 1]]], so if you regenerate the plot as pic2 you can get your annotations back if you use:

Insert[pic2, Rest[pic[[1, 1]]], {1, 1}]

I remember David Park (author of the Presentations package) being vehemently opposed to manual annotations. I have done quite some programmatic labeling myself, but sometimes placing labels under program control is just too difficult, like here (note that I don't like PlotLegends much, especially because some of the colors are clos开发者_JS百科e to each other):

It was already too late for my kludge, having thrown away the plot originals, but I wonder what the current state of thinking on this issue is.

• Are there better ways to do this?
• How general is this method? Does it work in all plot and chart types?
• Does it work in all versions? (above 5.2)
• Any WRI plans to improve handling of user additions in plots?

BTW The trick in my mathgroup posting differed slightly from the one shown above and used in the top-10 plot. The principle is the same, though.

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EDIT

I placed the code to make SO data plots like the one above in the Mathematica Toolbag.

EDIT

The code is now moved to the more appropriate question by Brett Champion: How do I access the StackOverflow API from Mathematica

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Personally, I agree with David Park that programmatic addition of annotation is superior. It's also likely to be more robust and work with future editions of Mathematica. I'd really like to see the drawing tools palette improved a bit and I'd like to see multiple annotations added by hand appear in the resulting Graphics object more clearly. If there were an inert Head like AddedAnnotation or some such, then you could find all these edits programmatically via

Cases[editedPic, _AddedAnnotation, Infinity]

As it is, I find myself digging through the InputForm of the image and I'm not certain that your Rest[pic[[1, 1]]] is always going to work, particularly in future versions.

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One method, which is a bit ugly but seems to work reasonably OK for minor plot annotations, is the following.

After adding annotations via the Drawings tools, the additional info is stored with the graphic and may be inspected by, for example, selecting the graphic bracket and using Show Expression (Shift-Command-E on a Mac). The additional information can usually be picked out by cut-and-paste or using Cases, and then may be added to the new modified plot using Epilog.

For example

Plot[Sin[x], {x, 0, 6 \[Pi]}]

Adding a few annotations gives the following:

Assigning the name plotgraphic to the above image, a new modified plot with added annotations present may be generated as follows (for example)

Labeled[Plot[Sin[x], {x, 0, 8 \[Pi]}, 
  Epilog -> Rest[Cases[plotgraphic, _List][[1]]]], "Sine Plot"]

giving

This can be awkward, to say the least, and the method no doubt can be improved. It is also probably along the lines of what others already do. Nevertheless, it goes give a plot where the annotations are present 'programmatically', and as no-one has mentioned Epilog, I decided it might be worth posting.