InDesign has a very limited choice of arrow heads, and when my editor asked for double arrows with a vertical bar at each end to indicate measurements in a math book, I had to come up with my own. Here’s what I did:
1. I found a cap K that was geometric, i.e. that looked like a left arrow head centered on a vertical line (I used Frutiger 55 Roman). I turned the K into an object (Type — Create outlnes), copied it and reversed the copy horizontally to have the “arrow” pointing right.
2. In a text box with an automatic height (Object — Text Frame Options… — Auto-Size — Height Only), I inserted both Ks, with a right indent tab between them (Type — Insert Special Character — Other — Right Indent Tab), then added a paragraph rule to link them, adjusting the thickness, the offset and the indents to create the illusion of an arrow.
Voilà! The text box can be used at any angles, widened or shortened as needed with no more adjustments to make. You can replace the tips with other characters from the same font or any other fonts, adjusting size, color, thickness, etc., as needed; just make sure to turned those characters into outlines to make the text box fit snuggly.
Here are some examples:
https://dl.dropboxusercontent.com/u/5070024/Custom%20Arrows%20%28sort%20of%29.pdf
Linda Szefer