Sets the default file save format if format is not specified

This function sets the file save format if format is not specified in save_e61 and the file extension is not provided in filename.

This function clears the default file save format specified in set_format.

Usage

set_format(format)

unset_format()

format: A string vector of file formats to save as. Accepts "svg", "pdf", "eps", "png", "jpg". For example c("svg", "pdf") will save 2 files with the same name to the same location to SVG and PDF formats. If the file format is specified in filename or by the set_format option, then this argument is ignored.

This function is used for its side effects.