Generic function to write new glyph types using loon's primitive glyphs
# S3 method for default
l_glyph_add(widget, type, label = "", ...)widget path as a string or as an object handle
loon-native non-primitive glyph type, one of 'text',
'serialaxes', 'image', '[polygon', or
'pointrange'
label of a glyph (currently shown only in the glyph inspector)
state arguments
Other glyph functions:
l_glyph_add_image(),
l_glyph_add_pointrange(),
l_glyph_add_polygon(),
l_glyph_add_serialaxes(),
l_glyph_add_text(),
l_glyph_add(),
l_glyph_delete(),
l_glyph_getLabel(),
l_glyph_getType(),
l_glyph_ids(),
l_glyph_relabel(),
l_primitiveGlyphs()