I would like to take an existing font and put a border around the characters (A-Za-z0-9). For example, I want to put a rectangle around the characters.
I would like to define the shape once and add it to/link it to each character. I thought I could use the composite feature, but I have been unable to figure out how to do that.
I was unable to find an existing post that covers this question.
You can do this, but the composites feature is best for creating accented characters áéíóú etc.
Pros: If you use composites, then need to modify the rectangle later, you only need to modify one rectangle.
Cons: In most fonts the characters are different widths, but your rectangle can only be one width. Also, you must compose the composites manually as the complete composites feature was never designed to do this. It is not difficult, just laborious.
Another way would be to just copy and paste a rectangle into each glyph from A-z and adjust the width to suit each letter. If you still want to use composites, take a look at my post in the Tutorials forum for making decorative fonts: New Fonts From Old For what you want to do, the rectangles need to be clockwise contours, while the contours of the letters all need to be reversed. Use the glyph validation toolbar to correct contour directions.
Composites are created using two or more formed characters thus unless you create the letters some place else in the font and use them in the (A-Z,a-z,0-9) locations with your box shape, composites can’t be used … That’s why composites work so well for the accented characters – the parts are defined elsewhere.
That means it’s a whole lot easier to create the font and manually copy/paste the box into each one (as Bhikkhu Pesala suggested) than to screw around with composites.