Compute canonical cache path for a TTF file
Arguments
- source
(
character(1)) Provider source identifier.- font_id
(
character(1)) Font id used for filenames.- subset
(
character(1)) Glyph subset identifier.- weight
(
integer(1)) Font weight.- style
(
character(1)) Style string (e.g. "normal", "italic").- cache_dir
(
character | NULL) Cache directory to use (default: NULL)
