See [method@PrintCompositor.set_header_format] for more information about the parameters.
%TRUE if you want a separator line to be printed.
a format string to print on the left of the footer.
a format string to print on the center of the footer.
a format string to print on the right of the footer.
See Implementation
See [method@PrintCompositor.set_header_format] for more information about the parameters.