hat not big enough

Question

I like to use Mathematica text cells for creating draft technical documents. When entering equations in a text cell, the ^ (hat accent) does not dynamically adjust its size to fit. It looks good if you enter x^, but if you wanted abc^, the ^ covers only the b. Anyone know how to make the ^ (and other accents) adjust to the size of the text?

Answer 1

This answer is just a quick hack. I think that to make true extensible character might not be something that an end-user can do...

Anyway, redefine the formatting for OverHat using

OverHat /: MakeBoxes[OverHat[a_], form_] := 
 With[{s = First[Rasterize[a, "RasterSize"]], 
   ab = MakeBoxes[a]}, With[{sl = N[2 Log[2 s]]},
   InterpretationBox[OverscriptBox[ab, 
     TagBox[GraphicsBox[LineBox[{{-s, 0}, {0, sl}, {s, 0}}], 
       ImageSize -> {s, Automatic}], "LongOverHat", 
      Selectable -> False]], OverHat[a]]]]

Then, just type in the expression as per normal, e.g., , and then select the OverHat expression and reformat the boxes using the menu command Cell > Convert To > Standard From (which can also be done using the shortcut CtrlShiftN) to get . The FullForm of this expression is OverHat[abc].

Here's an example showing how the modified OverHat scales for longer expressions

The MakeBoxes command also works with TraditionalForm (CtrlShiftT), but you might want to modify it to include an AdjustmentBox[..., BoxBaselineShift -> b] in order to get the vertical spacing looking right.