My purpose is to create the two characters for the imaginary unit i and for the Napier number e as seen below. Now, the aim is to do this in the Latin Modern Roman Italic font. So in Inkscape, I type the e in the correct font, but then I cannot figure out how could I place that white stripes that run all along the border of the letter. Any suggestion? Also, once the symbol is created, how do I make it become a symbol form LaTeX?
In Inkscape, you could use something like Times New Roman Italic, type an e, and convert to outlines using Path > Object to Path. Then add a stroke with the Pen Tool, convert the stroke to a path using Path > Stroke to Path, and then select both shapes, and join them using Path > Union. Then export it as a plain SVG, or as a PDF.
You will need to edit the font file itself and there's a number of tools you can use for that to either update an existing character or add a new one based on an existing character. See these questions:
